// Copyright 2017, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package cmp determines equality of values.
//
// This package is intended to be a more powerful and safer alternative to
// [reflect.DeepEqual] for comparing whether two values are semantically equal.
// It is intended to only be used in tests, as performance is not a goal and
// it may panic if it cannot compare the values. Its propensity towards
// panicking means that its unsuitable for production environments where a
// spurious panic may be fatal.
//
// The primary features of cmp are:
//
// - When the default behavior of equality does not suit the test's needs,
// custom equality functions can override the equality operation.
// For example, an equality function may report floats as equal so long as
// they are within some tolerance of each other.
//
// - Types with an Equal method (e.g., [time.Time.Equal]) may use that method
// to determine equality. This allows package authors to determine
// the equality operation for the types that they define.
//
// - If no custom equality functions are used and no Equal method is defined,
// equality is determined by recursively comparing the primitive kinds on
// both values, much like [reflect.DeepEqual]. Unlike [reflect.DeepEqual],
// unexported fields are not compared by default; they result in panics
// unless suppressed by using an [Ignore] option
// (see [github.com/google/go-cmp/cmp/cmpopts.IgnoreUnexported])
// or explicitly compared using the [Exporter] option.
package cmp
import (
"fmt"
"reflect"
"strings"
"github.com/google/go-cmp/cmp/internal/diff"
"github.com/google/go-cmp/cmp/internal/function"
"github.com/google/go-cmp/cmp/internal/value"
)
// TODO(≥go1.18): Use any instead of interface{}.
// Equal reports whether x and y are equal by recursively applying the
// following rules in the given order to x and y and all of their sub-values:
//
// - Let S be the set of all [Ignore], [Transformer], and [Comparer] options that
// remain after applying all path filters, value filters, and type filters.
// If at least one [Ignore] exists in S, then the comparison is ignored.
// If the number of [Transformer] and [Comparer] options in S is non-zero,
// then Equal panics because it is ambiguous which option to use.
// If S contains a single [Transformer], then use that to transform
// the current values and recursively call Equal on the output values.
// If S contains a single [Comparer], then use that to compare the current values.
// Otherwise, evaluation proceeds to the next rule.
//
// - If the values have an Equal method of the form "(T) Equal(T) bool" or
// "(T) Equal(I) bool" where T is assignable to I, then use the result of
// x.Equal(y) even if x or y is nil. Otherwise, no such method exists and
// evaluation proceeds to the next rule.
//
// - Lastly, try to compare x and y based on their basic kinds.
// Simple kinds like booleans, integers, floats, complex numbers, strings,
// and channels are compared using the equivalent of the == operator in Go.
// Functions are only equal if they are both nil, otherwise they are unequal.
//
// Structs are equal if recursively calling Equal on all fields report equal.
// If a struct contains unexported fields, Equal panics unless an [Ignore] option
// (e.g., [github.com/google/go-cmp/cmp/cmpopts.IgnoreUnexported]) ignores that field
// or the [Exporter] option explicitly permits comparing the unexported field.
//
// Slices are equal if they are both nil or both non-nil, where recursively
// calling Equal on all non-ignored slice or array elements report equal.
// Empty non-nil slices and nil slices are not equal; to equate empty slices,
// consider using [github.com/google/go-cmp/cmp/cmpopts.EquateEmpty].
//
// Maps are equal if they are both nil or both non-nil, where recursively
// calling Equal on all non-ignored map entries report equal.
// Map keys are equal according to the == operator.
// To use custom comparisons for map keys, consider using
// [github.com/google/go-cmp/cmp/cmpopts.SortMaps].
// Empty non-nil maps and nil maps are not equal; to equate empty maps,
// consider using [github.com/google/go-cmp/cmp/cmpopts.EquateEmpty].
//
// Pointers and interfaces are equal if they are both nil or both non-nil,
// where they have the same underlying concrete type and recursively
// calling Equal on the underlying values reports equal.
//
// Before recursing into a pointer, slice element, or map, the current path
// is checked to detect whether the address has already been visited.
// If there is a cycle, then the pointed at values are considered equal
// only if both addresses were previously visited in the same path step.
func Equal(x, y interface{}, opts ...Option) bool {
s := newState(opts)
s.compareAny(rootStep(x, y))
return s.result.Equal()
}
// Diff returns a human-readable report of the differences between two values:
// y - x. It returns an empty string if and only if Equal returns true for the
// same input values and options.
//
// The output is displayed as a literal in pseudo-Go syntax.
// At the start of each line, a "-" prefix indicates an element removed from x,
// a "+" prefix to indicates an element added from y, and the lack of a prefix
// indicates an element common to both x and y. If possible, the output
// uses fmt.Stringer.String or error.Error methods to produce more humanly
// readable outputs. In such cases, the string is prefixed with either an
// 's' or 'e' character, respectively, to indicate that the method was called.
//
// Do not depend on this output being stable. If you need the ability to
// programmatically interpret the difference, consider using a custom Reporter.
func Diff(x, y interface{}, opts ...Option) string {
s := newState(opts)
// Optimization: If there are no other reporters, we can optimize for the
// common case where the result is equal (and thus no reported difference).
// This avoids the expensive construction of a difference tree.
if len(s.reporters) == 0 {
s.compareAny(rootStep(x, y))
if s.result.Equal() {
return ""
}
s.result = diff.Result{} // Reset results
}
r := new(defaultReporter)
s.reporters = append(s.reporters, reporter{r})
s.compareAny(rootStep(x, y))
d := r.String()
if (d == "") != s.result.Equal() {
panic("inconsistent difference and equality results")
}
return d
}
// rootStep constructs the first path step. If x and y have differing types,
// then they are stored within an empty interface type.
func rootStep(x, y interface{}) PathStep {
vx := reflect.ValueOf(x)
vy := reflect.ValueOf(y)
// If the inputs are different types, auto-wrap them in an empty interface
// so that they have the same parent type.
var t reflect.Type
if !vx.IsValid() || !vy.IsValid() || vx.Type() != vy.Type() {
t = anyType
if vx.IsValid() {
vvx := reflect.New(t).Elem()
vvx.Set(vx)
vx = vvx
}
if vy.IsValid() {
vvy := reflect.New(t).Elem()
vvy.Set(vy)
vy = vvy
}
} else {
t = vx.Type()
}
return &pathStep{t, vx, vy}
}
type state struct {
// These fields represent the "comparison state".
// Calling statelessCompare must not result in observable changes to these.
result diff.Result // The current result of comparison
curPath Path // The current path in the value tree
curPtrs pointerPath // The current set of visited pointers
reporters []reporter // Optional reporters
// recChecker checks for infinite cycles applying the same set of
// transformers upon the output of itself.
recChecker recChecker
// dynChecker triggers pseudo-random checks for option correctness.
// It is safe for statelessCompare to mutate this value.
dynChecker dynChecker
// These fields, once set by processOption, will not change.
exporters []exporter // List of exporters for structs with unexported fields
opts Options // List of all fundamental and filter options
}
func newState(opts []Option) *state {
// Always ensure a validator option exists to validate the inputs.
s := &state{opts: Options{validator{}}}
s.curPtrs.Init()
s.processOption(Options(opts))
return s
}
func (s *state) processOption(opt Option) {
switch opt := opt.(type) {
case nil:
case Options:
for _, o := range opt {
s.processOption(o)
}
case coreOption:
type filtered interface {
isFiltered() bool
}
if fopt, ok := opt.(filtered); ok && !fopt.isFiltered() {
panic(fmt.Sprintf("cannot use an unfiltered option: %v", opt))
}
s.opts = append(s.opts, opt)
case exporter:
s.exporters = append(s.exporters, opt)
case reporter:
s.reporters = append(s.reporters, opt)
default:
panic(fmt.Sprintf("unknown option %T", opt))
}
}
// statelessCompare compares two values and returns the result.
// This function is stateless in that it does not alter the current result,
// or output to any registered reporters.
func (s *state) statelessCompare(step PathStep) diff.Result {
// We do not save and restore curPath and curPtrs because all of the
// compareX methods should properly push and pop from them.
// It is an implementation bug if the contents of the paths differ from
// when calling this function to when returning from it.
oldResult, oldReporters := s.result, s.reporters
s.result = diff.Result{} // Reset result
s.reporters = nil // Remove reporters to avoid spurious printouts
s.compareAny(step)
res := s.result
s.result, s.reporters = oldResult, oldReporters
return res
}
func (s *state) compareAny(step PathStep) {
// Update the path stack.
s.curPath.push(step)
defer s.curPath.pop()
for _, r := range s.reporters {
r.PushStep(step)
defer r.PopStep()
}
s.recChecker.Check(s.curPath)
// Cycle-detection for slice elements (see NOTE in compareSlice).
t := step.Type()
vx, vy := step.Values()
if si, ok := step.(SliceIndex); ok && si.isSlice && vx.IsValid() && vy.IsValid() {
px, py := vx.Addr(), vy.Addr()
if eq, visited := s.curPtrs.Push(px, py); visited {
s.report(eq, reportByCycle)
return
}
defer s.curPtrs.Pop(px, py)
}
// Rule 1: Check whether an option applies on this node in the value tree.
if s.tryOptions(t, vx, vy) {
return
}
// Rule 2: Check whether the type has a valid Equal method.
if s.tryMethod(t, vx, vy) {
return
}
// Rule 3: Compare based on the underlying kind.
switch t.Kind() {
case reflect.Bool:
s.report(vx.Bool() == vy.Bool(), 0)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
s.report(vx.Int() == vy.Int(), 0)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
s.report(vx.Uint() == vy.Uint(), 0)
case reflect.Float32, reflect.Float64:
s.report(vx.Float() == vy.Float(), 0)
case reflect.Complex64, reflect.Complex128:
s.report(vx.Complex() == vy.Complex(), 0)
case reflect.String:
s.report(vx.String() == vy.String(), 0)
case reflect.Chan, reflect.UnsafePointer:
s.report(vx.Pointer() == vy.Pointer(), 0)
case reflect.Func:
s.report(vx.IsNil() && vy.IsNil(), 0)
case reflect.Struct:
s.compareStruct(t, vx, vy)
case reflect.Slice, reflect.Array:
s.compareSlice(t, vx, vy)
case reflect.Map:
s.compareMap(t, vx, vy)
case reflect.Ptr:
s.comparePtr(t, vx, vy)
case reflect.Interface:
s.compareInterface(t, vx, vy)
default:
panic(fmt.Sprintf("%v kind not handled", t.Kind()))
}
}
func (s *state) tryOptions(t reflect.Type, vx, vy reflect.Value) bool {
// Evaluate all filters and apply the remaining options.
if opt := s.opts.filter(s, t, vx, vy); opt != nil {
opt.apply(s, vx, vy)
return true
}
return false
}
func (s *state) tryMethod(t reflect.Type, vx, vy reflect.Value) bool {
// Check if this type even has an Equal method.
m, ok := t.MethodByName("Equal")
if !ok || !function.IsType(m.Type, function.EqualAssignable) {
return false
}
eq := s.callTTBFunc(m.Func, vx, vy)
s.report(eq, reportByMethod)
return true
}
func (s *state) callTRFunc(f, v reflect.Value, step Transform) reflect.Value {
if !s.dynChecker.Next() {
return f.Call([]reflect.Value{v})[0]
}
// Run the function twice and ensure that we get the same results back.
// We run in goroutines so that the race detector (if enabled) can detect
// unsafe mutations to the input.
c := make(chan reflect.Value)
go detectRaces(c, f, v)
got := <-c
want := f.Call([]reflect.Value{v})[0]
if step.vx, step.vy = got, want; !s.statelessCompare(step).Equal() {
// To avoid false-positives with non-reflexive equality operations,
// we sanity check whether a value is equal to itself.
if step.vx, step.vy = want, want; !s.statelessCompare(step).Equal() {
return want
}
panic(fmt.Sprintf("non-deterministic function detected: %s", function.NameOf(f)))
}
return want
}
func (s *state) callTTBFunc(f, x, y reflect.Value) bool {
if !s.dynChecker.Next() {
return f.Call([]reflect.Value{x, y})[0].Bool()
}
// Swapping the input arguments is sufficient to check that
// f is symmetric and deterministic.
// We run in goroutines so that the race detector (if enabled) can detect
// unsafe mutations to the input.
c := make(chan reflect.Value)
go detectRaces(c, f, y, x)
got := <-c
want := f.Call([]reflect.Value{x, y})[0].Bool()
if !got.IsValid() || got.Bool() != want {
panic(fmt.Sprintf("non-deterministic or non-symmetric function detected: %s", function.NameOf(f)))
}
return want
}
func detectRaces(c chan<- reflect.Value, f reflect.Value, vs ...reflect.Value) {
var ret reflect.Value
defer func() {
recover() // Ignore panics, let the other call to f panic instead
c <- ret
}()
ret = f.Call(vs)[0]
}
func (s *state) compareStruct(t reflect.Type, vx, vy reflect.Value) {
var addr bool
var vax, vay reflect.Value // Addressable versions of vx and vy
var mayForce, mayForceInit bool
step := StructField{&structField{}}
for i := 0; i < t.NumField(); i++ {
step.typ = t.Field(i).Type
step.vx = vx.Field(i)
step.vy = vy.Field(i)
step.name = t.Field(i).Name
step.idx = i
step.unexported = !isExported(step.name)
if step.unexported {
if step.name == "_" {
continue
}
// Defer checking of unexported fields until later to give an
// Ignore a chance to ignore the field.
if !vax.IsValid() || !vay.IsValid() {
// For retrieveUnexportedField to work, the parent struct must
// be addressable. Create a new copy of the values if
// necessary to make them addressable.
addr = vx.CanAddr() || vy.CanAddr()
vax = makeAddressable(vx)
vay = makeAddressable(vy)
}
if !mayForceInit {
for _, xf := range s.exporters {
mayForce = mayForce || xf(t)
}
mayForceInit = true
}
step.mayForce = mayForce
step.paddr = addr
step.pvx = vax
step.pvy = vay
step.field = t.Field(i)
}
s.compareAny(step)
}
}
func (s *state) compareSlice(t reflect.Type, vx, vy reflect.Value) {
isSlice := t.Kind() == reflect.Slice
if isSlice && (vx.IsNil() || vy.IsNil()) {
s.report(vx.IsNil() && vy.IsNil(), 0)
return
}
// NOTE: It is incorrect to call curPtrs.Push on the slice header pointer
// since slices represents a list of pointers, rather than a single pointer.
// The pointer checking logic must be handled on a per-element basis
// in compareAny.
//
// A slice header (see reflect.SliceHeader) in Go is a tuple of a starting
// pointer P, a length N, and a capacity C. Supposing each slice element has
// a memory size of M, then the slice is equivalent to the list of pointers:
// [P+i*M for i in range(N)]
//
// For example, v[:0] and v[:1] are slices with the same starting pointer,
// but they are clearly different values. Using the slice pointer alone
// violates the assumption that equal pointers implies equal values.
step := SliceIndex{&sliceIndex{pathStep: pathStep{typ: t.Elem()}, isSlice: isSlice}}
withIndexes := func(ix, iy int) SliceIndex {
if ix >= 0 {
step.vx, step.xkey = vx.Index(ix), ix
} else {
step.vx, step.xkey = reflect.Value{}, -1
}
if iy >= 0 {
step.vy, step.ykey = vy.Index(iy), iy
} else {
step.vy, step.ykey = reflect.Value{}, -1
}
return step
}
// Ignore options are able to ignore missing elements in a slice.
// However, detecting these reliably requires an optimal differencing
// algorithm, for which diff.Difference is not.
//
// Instead, we first iterate through both slices to detect which elements
// would be ignored if standing alone. The index of non-discarded elements
// are stored in a separate slice, which diffing is then performed on.
var indexesX, indexesY []int
var ignoredX, ignoredY []bool
for ix := 0; ix < vx.Len(); ix++ {
ignored := s.statelessCompare(withIndexes(ix, -1)).NumDiff == 0
if !ignored {
indexesX = append(indexesX, ix)
}
ignoredX = append(ignoredX, ignored)
}
for iy := 0; iy < vy.Len(); iy++ {
ignored := s.statelessCompare(withIndexes(-1, iy)).NumDiff == 0
if !ignored {
indexesY = append(indexesY, iy)
}
ignoredY = append(ignoredY, ignored)
}
// Compute an edit-script for slices vx and vy (excluding ignored elements).
edits := diff.Difference(len(indexesX), len(indexesY), func(ix, iy int) diff.Result {
return s.statelessCompare(withIndexes(indexesX[ix], indexesY[iy]))
})
// Replay the ignore-scripts and the edit-script.
var ix, iy int
for ix < vx.Len() || iy < vy.Len() {
var e diff.EditType
switch {
case ix < len(ignoredX) && ignoredX[ix]:
e = diff.UniqueX
case iy < len(ignoredY) && ignoredY[iy]:
e = diff.UniqueY
default:
e, edits = edits[0], edits[1:]
}
switch e {
case diff.UniqueX:
s.compareAny(withIndexes(ix, -1))
ix++
case diff.UniqueY:
s.compareAny(withIndexes(-1, iy))
iy++
default:
s.compareAny(withIndexes(ix, iy))
ix++
iy++
}
}
}
func (s *state) compareMap(t reflect.Type, vx, vy reflect.Value) {
if vx.IsNil() || vy.IsNil() {
s.report(vx.IsNil() && vy.IsNil(), 0)
return
}
// Cycle-detection for maps.
if eq, visited := s.curPtrs.Push(vx, vy); visited {
s.report(eq, reportByCycle)
return
}
defer s.curPtrs.Pop(vx, vy)
// We combine and sort the two map keys so that we can perform the
// comparisons in a deterministic order.
step := MapIndex{&mapIndex{pathStep: pathStep{typ: t.Elem()}}}
for _, k := range value.SortKeys(append(vx.MapKeys(), vy.MapKeys()...)) {
step.vx = vx.MapIndex(k)
step.vy = vy.MapIndex(k)
step.key = k
if !step.vx.IsValid() && !step.vy.IsValid() {
// It is possible for both vx and vy to be invalid if the
// key contained a NaN value in it.
//
// Even with the ability to retrieve NaN keys in Go 1.12,
// there still isn't a sensible way to compare the values since
// a NaN key may map to multiple unordered values.
// The most reasonable way to compare NaNs would be to compare the
// set of values. However, this is impossible to do efficiently
// since set equality is provably an O(n^2) operation given only
// an Equal function. If we had a Less function or Hash function,
// this could be done in O(n*log(n)) or O(n), respectively.
//
// Rather than adding complex logic to deal with NaNs, make it
// the user's responsibility to compare such obscure maps.
const help = "consider providing a Comparer to compare the map"
panic(fmt.Sprintf("%#v has map key with NaNs\n%s", s.curPath, help))
}
s.compareAny(step)
}
}
func (s *state) comparePtr(t reflect.Type, vx, vy reflect.Value) {
if vx.IsNil() || vy.IsNil() {
s.report(vx.IsNil() && vy.IsNil(), 0)
return
}
// Cycle-detection for pointers.
if eq, visited := s.curPtrs.Push(vx, vy); visited {
s.report(eq, reportByCycle)
return
}
defer s.curPtrs.Pop(vx, vy)
vx, vy = vx.Elem(), vy.Elem()
s.compareAny(Indirect{&indirect{pathStep{t.Elem(), vx, vy}}})
}
func (s *state) compareInterface(t reflect.Type, vx, vy reflect.Value) {
if vx.IsNil() || vy.IsNil() {
s.report(vx.IsNil() && vy.IsNil(), 0)
return
}
vx, vy = vx.Elem(), vy.Elem()
if vx.Type() != vy.Type() {
s.report(false, 0)
return
}
s.compareAny(TypeAssertion{&typeAssertion{pathStep{vx.Type(), vx, vy}}})
}
func (s *state) report(eq bool, rf resultFlags) {
if rf&reportByIgnore == 0 {
if eq {
s.result.NumSame++
rf |= reportEqual
} else {
s.result.NumDiff++
rf |= reportUnequal
}
}
for _, r := range s.reporters {
r.Report(Result{flags: rf})
}
}
// recChecker tracks the state needed to periodically perform checks that
// user provided transformers are not stuck in an infinitely recursive cycle.
type recChecker struct{ next int }
// Check scans the Path for any recursive transformers and panics when any
// recursive transformers are detected. Note that the presence of a
// recursive Transformer does not necessarily imply an infinite cycle.
// As such, this check only activates after some minimal number of path steps.
func (rc *recChecker) Check(p Path) {
const minLen = 1 << 16
if rc.next == 0 {
rc.next = minLen
}
if len(p) < rc.next {
return
}
rc.next <<= 1
// Check whether the same transformer has appeared at least twice.
var ss []string
m := map[Option]int{}
for _, ps := range p {
if t, ok := ps.(Transform); ok {
t := t.Option()
if m[t] == 1 { // Transformer was used exactly once before
tf := t.(*transformer).fnc.Type()
ss = append(ss, fmt.Sprintf("%v: %v => %v", t, tf.In(0), tf.Out(0)))
}
m[t]++
}
}
if len(ss) > 0 {
const warning = "recursive set of Transformers detected"
const help = "consider using cmpopts.AcyclicTransformer"
set := strings.Join(ss, "\n\t")
panic(fmt.Sprintf("%s:\n\t%s\n%s", warning, set, help))
}
}
// dynChecker tracks the state needed to periodically perform checks that
// user provided functions are symmetric and deterministic.
// The zero value is safe for immediate use.
type dynChecker struct{ curr, next int }
// Next increments the state and reports whether a check should be performed.
//
// Checks occur every Nth function call, where N is a triangular number:
//
// 0 1 3 6 10 15 21 28 36 45 55 66 78 91 105 120 136 153 171 190 ...
//
// See https://en.wikipedia.org/wiki/Triangular_number
//
// This sequence ensures that the cost of checks drops significantly as
// the number of functions calls grows larger.
func (dc *dynChecker) Next() bool {
ok := dc.curr == dc.next
if ok {
dc.curr = 0
dc.next++
}
dc.curr++
return ok
}
// makeAddressable returns a value that is always addressable.
// It returns the input verbatim if it is already addressable,
// otherwise it creates a new value and returns an addressable copy.
func makeAddressable(v reflect.Value) reflect.Value {
if v.CanAddr() {
return v
}
vc := reflect.New(v.Type()).Elem()
vc.Set(v)
return vc
}
// Copyright 2017, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cmp
import (
"reflect"
"unsafe"
)
// retrieveUnexportedField uses unsafe to forcibly retrieve any field from
// a struct such that the value has read-write permissions.
//
// The parent struct, v, must be addressable, while f must be a StructField
// describing the field to retrieve. If addr is false,
// then the returned value will be shallowed copied to be non-addressable.
func retrieveUnexportedField(v reflect.Value, f reflect.StructField, addr bool) reflect.Value {
ve := reflect.NewAt(f.Type, unsafe.Pointer(uintptr(unsafe.Pointer(v.UnsafeAddr()))+f.Offset)).Elem()
if !addr {
// A field is addressable if and only if the struct is addressable.
// If the original parent value was not addressable, shallow copy the
// value to make it non-addressable to avoid leaking an implementation
// detail of how forcibly exporting a field works.
if ve.Kind() == reflect.Interface && ve.IsNil() {
return reflect.Zero(f.Type)
}
return reflect.ValueOf(ve.Interface()).Convert(f.Type)
}
return ve
}
// Copyright 2017, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cmp
import (
"fmt"
"reflect"
"regexp"
"strings"
"github.com/google/go-cmp/cmp/internal/function"
)
// Option configures for specific behavior of [Equal] and [Diff]. In particular,
// the fundamental Option functions ([Ignore], [Transformer], and [Comparer]),
// configure how equality is determined.
//
// The fundamental options may be composed with filters ([FilterPath] and
// [FilterValues]) to control the scope over which they are applied.
//
// The [github.com/google/go-cmp/cmp/cmpopts] package provides helper functions
// for creating options that may be used with [Equal] and [Diff].
type Option interface {
// filter applies all filters and returns the option that remains.
// Each option may only read s.curPath and call s.callTTBFunc.
//
// An Options is returned only if multiple comparers or transformers
// can apply simultaneously and will only contain values of those types
// or sub-Options containing values of those types.
filter(s *state, t reflect.Type, vx, vy reflect.Value) applicableOption
}
// applicableOption represents the following types:
//
// Fundamental: ignore | validator | *comparer | *transformer
// Grouping: Options
type applicableOption interface {
Option
// apply executes the option, which may mutate s or panic.
apply(s *state, vx, vy reflect.Value)
}
// coreOption represents the following types:
//
// Fundamental: ignore | validator | *comparer | *transformer
// Filters: *pathFilter | *valuesFilter
type coreOption interface {
Option
isCore()
}
type core struct{}
func (core) isCore() {}
// Options is a list of [Option] values that also satisfies the [Option] interface.
// Helper comparison packages may return an Options value when packing multiple
// [Option] values into a single [Option]. When this package processes an Options,
// it will be implicitly expanded into a flat list.
//
// Applying a filter on an Options is equivalent to applying that same filter
// on all individual options held within.
type Options []Option
func (opts Options) filter(s *state, t reflect.Type, vx, vy reflect.Value) (out applicableOption) {
for _, opt := range opts {
switch opt := opt.filter(s, t, vx, vy); opt.(type) {
case ignore:
return ignore{} // Only ignore can short-circuit evaluation
case validator:
out = validator{} // Takes precedence over comparer or transformer
case *comparer, *transformer, Options:
switch out.(type) {
case nil:
out = opt
case validator:
// Keep validator
case *comparer, *transformer, Options:
out = Options{out, opt} // Conflicting comparers or transformers
}
}
}
return out
}
func (opts Options) apply(s *state, _, _ reflect.Value) {
const warning = "ambiguous set of applicable options"
const help = "consider using filters to ensure at most one Comparer or Transformer may apply"
var ss []string
for _, opt := range flattenOptions(nil, opts) {
ss = append(ss, fmt.Sprint(opt))
}
set := strings.Join(ss, "\n\t")
panic(fmt.Sprintf("%s at %#v:\n\t%s\n%s", warning, s.curPath, set, help))
}
func (opts Options) String() string {
var ss []string
for _, opt := range opts {
ss = append(ss, fmt.Sprint(opt))
}
return fmt.Sprintf("Options{%s}", strings.Join(ss, ", "))
}
// FilterPath returns a new [Option] where opt is only evaluated if filter f
// returns true for the current [Path] in the value tree.
//
// This filter is called even if a slice element or map entry is missing and
// provides an opportunity to ignore such cases. The filter function must be
// symmetric such that the filter result is identical regardless of whether the
// missing value is from x or y.
//
// The option passed in may be an [Ignore], [Transformer], [Comparer], [Options], or
// a previously filtered [Option].
func FilterPath(f func(Path) bool, opt Option) Option {
if f == nil {
panic("invalid path filter function")
}
if opt := normalizeOption(opt); opt != nil {
return &pathFilter{fnc: f, opt: opt}
}
return nil
}
type pathFilter struct {
core
fnc func(Path) bool
opt Option
}
func (f pathFilter) filter(s *state, t reflect.Type, vx, vy reflect.Value) applicableOption {
if f.fnc(s.curPath) {
return f.opt.filter(s, t, vx, vy)
}
return nil
}
func (f pathFilter) String() string {
return fmt.Sprintf("FilterPath(%s, %v)", function.NameOf(reflect.ValueOf(f.fnc)), f.opt)
}
// FilterValues returns a new [Option] where opt is only evaluated if filter f,
// which is a function of the form "func(T, T) bool", returns true for the
// current pair of values being compared. If either value is invalid or
// the type of the values is not assignable to T, then this filter implicitly
// returns false.
//
// The filter function must be
// symmetric (i.e., agnostic to the order of the inputs) and
// deterministic (i.e., produces the same result when given the same inputs).
// If T is an interface, it is possible that f is called with two values with
// different concrete types that both implement T.
//
// The option passed in may be an [Ignore], [Transformer], [Comparer], [Options], or
// a previously filtered [Option].
func FilterValues(f interface{}, opt Option) Option {
v := reflect.ValueOf(f)
if !function.IsType(v.Type(), function.ValueFilter) || v.IsNil() {
panic(fmt.Sprintf("invalid values filter function: %T", f))
}
if opt := normalizeOption(opt); opt != nil {
vf := &valuesFilter{fnc: v, opt: opt}
if ti := v.Type().In(0); ti.Kind() != reflect.Interface || ti.NumMethod() > 0 {
vf.typ = ti
}
return vf
}
return nil
}
type valuesFilter struct {
core
typ reflect.Type // T
fnc reflect.Value // func(T, T) bool
opt Option
}
func (f valuesFilter) filter(s *state, t reflect.Type, vx, vy reflect.Value) applicableOption {
if !vx.IsValid() || !vx.CanInterface() || !vy.IsValid() || !vy.CanInterface() {
return nil
}
if (f.typ == nil || t.AssignableTo(f.typ)) && s.callTTBFunc(f.fnc, vx, vy) {
return f.opt.filter(s, t, vx, vy)
}
return nil
}
func (f valuesFilter) String() string {
return fmt.Sprintf("FilterValues(%s, %v)", function.NameOf(f.fnc), f.opt)
}
// Ignore is an [Option] that causes all comparisons to be ignored.
// This value is intended to be combined with [FilterPath] or [FilterValues].
// It is an error to pass an unfiltered Ignore option to [Equal].
func Ignore() Option { return ignore{} }
type ignore struct{ core }
func (ignore) isFiltered() bool { return false }
func (ignore) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption { return ignore{} }
func (ignore) apply(s *state, _, _ reflect.Value) { s.report(true, reportByIgnore) }
func (ignore) String() string { return "Ignore()" }
// validator is a sentinel Option type to indicate that some options could not
// be evaluated due to unexported fields, missing slice elements, or
// missing map entries. Both values are validator only for unexported fields.
type validator struct{ core }
func (validator) filter(_ *state, _ reflect.Type, vx, vy reflect.Value) applicableOption {
if !vx.IsValid() || !vy.IsValid() {
return validator{}
}
if !vx.CanInterface() || !vy.CanInterface() {
return validator{}
}
return nil
}
func (validator) apply(s *state, vx, vy reflect.Value) {
// Implies missing slice element or map entry.
if !vx.IsValid() || !vy.IsValid() {
s.report(vx.IsValid() == vy.IsValid(), 0)
return
}
// Unable to Interface implies unexported field without visibility access.
if !vx.CanInterface() || !vy.CanInterface() {
help := "consider using a custom Comparer; if you control the implementation of type, you can also consider using an Exporter, AllowUnexported, or cmpopts.IgnoreUnexported"
var name string
if t := s.curPath.Index(-2).Type(); t.Name() != "" {
// Named type with unexported fields.
name = fmt.Sprintf("%q.%v", t.PkgPath(), t.Name()) // e.g., "path/to/package".MyType
isProtoMessage := func(t reflect.Type) bool {
m, ok := reflect.PointerTo(t).MethodByName("ProtoReflect")
return ok && m.Type.NumIn() == 1 && m.Type.NumOut() == 1 &&
m.Type.Out(0).PkgPath() == "google.golang.org/protobuf/reflect/protoreflect" &&
m.Type.Out(0).Name() == "Message"
}
if isProtoMessage(t) {
help = `consider using "google.golang.org/protobuf/testing/protocmp".Transform to compare proto.Message types`
} else if _, ok := reflect.New(t).Interface().(error); ok {
help = "consider using cmpopts.EquateErrors to compare error values"
} else if t.Comparable() {
help = "consider using cmpopts.EquateComparable to compare comparable Go types"
}
} else {
// Unnamed type with unexported fields. Derive PkgPath from field.
var pkgPath string
for i := 0; i < t.NumField() && pkgPath == ""; i++ {
pkgPath = t.Field(i).PkgPath
}
name = fmt.Sprintf("%q.(%v)", pkgPath, t.String()) // e.g., "path/to/package".(struct { a int })
}
panic(fmt.Sprintf("cannot handle unexported field at %#v:\n\t%v\n%s", s.curPath, name, help))
}
panic("not reachable")
}
// identRx represents a valid identifier according to the Go specification.
const identRx = `[_\p{L}][_\p{L}\p{N}]*`
var identsRx = regexp.MustCompile(`^` + identRx + `(\.` + identRx + `)*$`)
// Transformer returns an [Option] that applies a transformation function that
// converts values of a certain type into that of another.
//
// The transformer f must be a function "func(T) R" that converts values of
// type T to those of type R and is implicitly filtered to input values
// assignable to T. The transformer must not mutate T in any way.
//
// To help prevent some cases of infinite recursive cycles applying the
// same transform to the output of itself (e.g., in the case where the
// input and output types are the same), an implicit filter is added such that
// a transformer is applicable only if that exact transformer is not already
// in the tail of the [Path] since the last non-[Transform] step.
// For situations where the implicit filter is still insufficient,
// consider using [github.com/google/go-cmp/cmp/cmpopts.AcyclicTransformer],
// which adds a filter to prevent the transformer from
// being recursively applied upon itself.
//
// The name is a user provided label that is used as the [Transform.Name] in the
// transformation [PathStep] (and eventually shown in the [Diff] output).
// The name must be a valid identifier or qualified identifier in Go syntax.
// If empty, an arbitrary name is used.
func Transformer(name string, f interface{}) Option {
v := reflect.ValueOf(f)
if !function.IsType(v.Type(), function.Transformer) || v.IsNil() {
panic(fmt.Sprintf("invalid transformer function: %T", f))
}
if name == "" {
name = function.NameOf(v)
if !identsRx.MatchString(name) {
name = "λ" // Lambda-symbol as placeholder name
}
} else if !identsRx.MatchString(name) {
panic(fmt.Sprintf("invalid name: %q", name))
}
tr := &transformer{name: name, fnc: reflect.ValueOf(f)}
if ti := v.Type().In(0); ti.Kind() != reflect.Interface || ti.NumMethod() > 0 {
tr.typ = ti
}
return tr
}
type transformer struct {
core
name string
typ reflect.Type // T
fnc reflect.Value // func(T) R
}
func (tr *transformer) isFiltered() bool { return tr.typ != nil }
func (tr *transformer) filter(s *state, t reflect.Type, _, _ reflect.Value) applicableOption {
for i := len(s.curPath) - 1; i >= 0; i-- {
if t, ok := s.curPath[i].(Transform); !ok {
break // Hit most recent non-Transform step
} else if tr == t.trans {
return nil // Cannot directly use same Transform
}
}
if tr.typ == nil || t.AssignableTo(tr.typ) {
return tr
}
return nil
}
func (tr *transformer) apply(s *state, vx, vy reflect.Value) {
step := Transform{&transform{pathStep{typ: tr.fnc.Type().Out(0)}, tr}}
vvx := s.callTRFunc(tr.fnc, vx, step)
vvy := s.callTRFunc(tr.fnc, vy, step)
step.vx, step.vy = vvx, vvy
s.compareAny(step)
}
func (tr transformer) String() string {
return fmt.Sprintf("Transformer(%s, %s)", tr.name, function.NameOf(tr.fnc))
}
// Comparer returns an [Option] that determines whether two values are equal
// to each other.
//
// The comparer f must be a function "func(T, T) bool" and is implicitly
// filtered to input values assignable to T. If T is an interface, it is
// possible that f is called with two values of different concrete types that
// both implement T.
//
// The equality function must be:
// - Symmetric: equal(x, y) == equal(y, x)
// - Deterministic: equal(x, y) == equal(x, y)
// - Pure: equal(x, y) does not modify x or y
func Comparer(f interface{}) Option {
v := reflect.ValueOf(f)
if !function.IsType(v.Type(), function.Equal) || v.IsNil() {
panic(fmt.Sprintf("invalid comparer function: %T", f))
}
cm := &comparer{fnc: v}
if ti := v.Type().In(0); ti.Kind() != reflect.Interface || ti.NumMethod() > 0 {
cm.typ = ti
}
return cm
}
type comparer struct {
core
typ reflect.Type // T
fnc reflect.Value // func(T, T) bool
}
func (cm *comparer) isFiltered() bool { return cm.typ != nil }
func (cm *comparer) filter(_ *state, t reflect.Type, _, _ reflect.Value) applicableOption {
if cm.typ == nil || t.AssignableTo(cm.typ) {
return cm
}
return nil
}
func (cm *comparer) apply(s *state, vx, vy reflect.Value) {
eq := s.callTTBFunc(cm.fnc, vx, vy)
s.report(eq, reportByFunc)
}
func (cm comparer) String() string {
return fmt.Sprintf("Comparer(%s)", function.NameOf(cm.fnc))
}
// Exporter returns an [Option] that specifies whether [Equal] is allowed to
// introspect into the unexported fields of certain struct types.
//
// Users of this option must understand that comparing on unexported fields
// from external packages is not safe since changes in the internal
// implementation of some external package may cause the result of [Equal]
// to unexpectedly change. However, it may be valid to use this option on types
// defined in an internal package where the semantic meaning of an unexported
// field is in the control of the user.
//
// In many cases, a custom [Comparer] should be used instead that defines
// equality as a function of the public API of a type rather than the underlying
// unexported implementation.
//
// For example, the [reflect.Type] documentation defines equality to be determined
// by the == operator on the interface (essentially performing a shallow pointer
// comparison) and most attempts to compare *[regexp.Regexp] types are interested
// in only checking that the regular expression strings are equal.
// Both of these are accomplished using [Comparer] options:
//
// Comparer(func(x, y reflect.Type) bool { return x == y })
// Comparer(func(x, y *regexp.Regexp) bool { return x.String() == y.String() })
//
// In other cases, the [github.com/google/go-cmp/cmp/cmpopts.IgnoreUnexported]
// option can be used to ignore all unexported fields on specified struct types.
func Exporter(f func(reflect.Type) bool) Option {
return exporter(f)
}
type exporter func(reflect.Type) bool
func (exporter) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption {
panic("not implemented")
}
// AllowUnexported returns an [Option] that allows [Equal] to forcibly introspect
// unexported fields of the specified struct types.
//
// See [Exporter] for the proper use of this option.
func AllowUnexported(types ...interface{}) Option {
m := make(map[reflect.Type]bool)
for _, typ := range types {
t := reflect.TypeOf(typ)
if t.Kind() != reflect.Struct {
panic(fmt.Sprintf("invalid struct type: %T", typ))
}
m[t] = true
}
return exporter(func(t reflect.Type) bool { return m[t] })
}
// Result represents the comparison result for a single node and
// is provided by cmp when calling Report (see [Reporter]).
type Result struct {
_ [0]func() // Make Result incomparable
flags resultFlags
}
// Equal reports whether the node was determined to be equal or not.
// As a special case, ignored nodes are considered equal.
func (r Result) Equal() bool {
return r.flags&(reportEqual|reportByIgnore) != 0
}
// ByIgnore reports whether the node is equal because it was ignored.
// This never reports true if [Result.Equal] reports false.
func (r Result) ByIgnore() bool {
return r.flags&reportByIgnore != 0
}
// ByMethod reports whether the Equal method determined equality.
func (r Result) ByMethod() bool {
return r.flags&reportByMethod != 0
}
// ByFunc reports whether a [Comparer] function determined equality.
func (r Result) ByFunc() bool {
return r.flags&reportByFunc != 0
}
// ByCycle reports whether a reference cycle was detected.
func (r Result) ByCycle() bool {
return r.flags&reportByCycle != 0
}
type resultFlags uint
const (
_ resultFlags = (1 << iota) / 2
reportEqual
reportUnequal
reportByIgnore
reportByMethod
reportByFunc
reportByCycle
)
// Reporter is an [Option] that can be passed to [Equal]. When [Equal] traverses
// the value trees, it calls PushStep as it descends into each node in the
// tree and PopStep as it ascend out of the node. The leaves of the tree are
// either compared (determined to be equal or not equal) or ignored and reported
// as such by calling the Report method.
func Reporter(r interface {
// PushStep is called when a tree-traversal operation is performed.
// The PathStep itself is only valid until the step is popped.
// The PathStep.Values are valid for the duration of the entire traversal
// and must not be mutated.
//
// Equal always calls PushStep at the start to provide an operation-less
// PathStep used to report the root values.
//
// Within a slice, the exact set of inserted, removed, or modified elements
// is unspecified and may change in future implementations.
// The entries of a map are iterated through in an unspecified order.
PushStep(PathStep)
// Report is called exactly once on leaf nodes to report whether the
// comparison identified the node as equal, unequal, or ignored.
// A leaf node is one that is immediately preceded by and followed by
// a pair of PushStep and PopStep calls.
Report(Result)
// PopStep ascends back up the value tree.
// There is always a matching pop call for every push call.
PopStep()
}) Option {
return reporter{r}
}
type reporter struct{ reporterIface }
type reporterIface interface {
PushStep(PathStep)
Report(Result)
PopStep()
}
func (reporter) filter(_ *state, _ reflect.Type, _, _ reflect.Value) applicableOption {
panic("not implemented")
}
// normalizeOption normalizes the input options such that all Options groups
// are flattened and groups with a single element are reduced to that element.
// Only coreOptions and Options containing coreOptions are allowed.
func normalizeOption(src Option) Option {
switch opts := flattenOptions(nil, Options{src}); len(opts) {
case 0:
return nil
case 1:
return opts[0]
default:
return opts
}
}
// flattenOptions copies all options in src to dst as a flat list.
// Only coreOptions and Options containing coreOptions are allowed.
func flattenOptions(dst, src Options) Options {
for _, opt := range src {
switch opt := opt.(type) {
case nil:
continue
case Options:
dst = flattenOptions(dst, opt)
case coreOption:
dst = append(dst, opt)
default:
panic(fmt.Sprintf("invalid option type: %T", opt))
}
}
return dst
}
// Copyright 2017, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cmp
import (
"fmt"
"reflect"
"strings"
"unicode"
"unicode/utf8"
"github.com/google/go-cmp/cmp/internal/value"
)
// Path is a list of [PathStep] describing the sequence of operations to get
// from some root type to the current position in the value tree.
// The first Path element is always an operation-less [PathStep] that exists
// simply to identify the initial type.
//
// When traversing structs with embedded structs, the embedded struct will
// always be accessed as a field before traversing the fields of the
// embedded struct themselves. That is, an exported field from the
// embedded struct will never be accessed directly from the parent struct.
type Path []PathStep
// PathStep is a union-type for specific operations to traverse
// a value's tree structure. Users of this package never need to implement
// these types as values of this type will be returned by this package.
//
// Implementations of this interface:
// - [StructField]
// - [SliceIndex]
// - [MapIndex]
// - [Indirect]
// - [TypeAssertion]
// - [Transform]
type PathStep interface {
String() string
// Type is the resulting type after performing the path step.
Type() reflect.Type
// Values is the resulting values after performing the path step.
// The type of each valid value is guaranteed to be identical to Type.
//
// In some cases, one or both may be invalid or have restrictions:
// - For StructField, both are not interface-able if the current field
// is unexported and the struct type is not explicitly permitted by
// an Exporter to traverse unexported fields.
// - For SliceIndex, one may be invalid if an element is missing from
// either the x or y slice.
// - For MapIndex, one may be invalid if an entry is missing from
// either the x or y map.
//
// The provided values must not be mutated.
Values() (vx, vy reflect.Value)
}
var (
_ PathStep = StructField{}
_ PathStep = SliceIndex{}
_ PathStep = MapIndex{}
_ PathStep = Indirect{}
_ PathStep = TypeAssertion{}
_ PathStep = Transform{}
)
func (pa *Path) push(s PathStep) {
*pa = append(*pa, s)
}
func (pa *Path) pop() {
*pa = (*pa)[:len(*pa)-1]
}
// Last returns the last [PathStep] in the Path.
// If the path is empty, this returns a non-nil [PathStep]
// that reports a nil [PathStep.Type].
func (pa Path) Last() PathStep {
return pa.Index(-1)
}
// Index returns the ith step in the Path and supports negative indexing.
// A negative index starts counting from the tail of the Path such that -1
// refers to the last step, -2 refers to the second-to-last step, and so on.
// If index is invalid, this returns a non-nil [PathStep]
// that reports a nil [PathStep.Type].
func (pa Path) Index(i int) PathStep {
if i < 0 {
i = len(pa) + i
}
if i < 0 || i >= len(pa) {
return pathStep{}
}
return pa[i]
}
// String returns the simplified path to a node.
// The simplified path only contains struct field accesses.
//
// For example:
//
// MyMap.MySlices.MyField
func (pa Path) String() string {
var ss []string
for _, s := range pa {
if _, ok := s.(StructField); ok {
ss = append(ss, s.String())
}
}
return strings.TrimPrefix(strings.Join(ss, ""), ".")
}
// GoString returns the path to a specific node using Go syntax.
//
// For example:
//
// (*root.MyMap["key"].(*mypkg.MyStruct).MySlices)[2][3].MyField
func (pa Path) GoString() string {
var ssPre, ssPost []string
var numIndirect int
for i, s := range pa {
var nextStep PathStep
if i+1 < len(pa) {
nextStep = pa[i+1]
}
switch s := s.(type) {
case Indirect:
numIndirect++
pPre, pPost := "(", ")"
switch nextStep.(type) {
case Indirect:
continue // Next step is indirection, so let them batch up
case StructField:
numIndirect-- // Automatic indirection on struct fields
case nil:
pPre, pPost = "", "" // Last step; no need for parenthesis
}
if numIndirect > 0 {
ssPre = append(ssPre, pPre+strings.Repeat("*", numIndirect))
ssPost = append(ssPost, pPost)
}
numIndirect = 0
continue
case Transform:
ssPre = append(ssPre, s.trans.name+"(")
ssPost = append(ssPost, ")")
continue
}
ssPost = append(ssPost, s.String())
}
for i, j := 0, len(ssPre)-1; i < j; i, j = i+1, j-1 {
ssPre[i], ssPre[j] = ssPre[j], ssPre[i]
}
return strings.Join(ssPre, "") + strings.Join(ssPost, "")
}
type pathStep struct {
typ reflect.Type
vx, vy reflect.Value
}
func (ps pathStep) Type() reflect.Type { return ps.typ }
func (ps pathStep) Values() (vx, vy reflect.Value) { return ps.vx, ps.vy }
func (ps pathStep) String() string {
if ps.typ == nil {
return "<nil>"
}
s := value.TypeString(ps.typ, false)
if s == "" || strings.ContainsAny(s, "{}\n") {
return "root" // Type too simple or complex to print
}
return fmt.Sprintf("{%s}", s)
}
// StructField is a [PathStep] that represents a struct field access
// on a field called [StructField.Name].
type StructField struct{ *structField }
type structField struct {
pathStep
name string
idx int
// These fields are used for forcibly accessing an unexported field.
// pvx, pvy, and field are only valid if unexported is true.
unexported bool
mayForce bool // Forcibly allow visibility
paddr bool // Was parent addressable?
pvx, pvy reflect.Value // Parent values (always addressable)
field reflect.StructField // Field information
}
func (sf StructField) Type() reflect.Type { return sf.typ }
func (sf StructField) Values() (vx, vy reflect.Value) {
if !sf.unexported {
return sf.vx, sf.vy // CanInterface reports true
}
// Forcibly obtain read-write access to an unexported struct field.
if sf.mayForce {
vx = retrieveUnexportedField(sf.pvx, sf.field, sf.paddr)
vy = retrieveUnexportedField(sf.pvy, sf.field, sf.paddr)
return vx, vy // CanInterface reports true
}
return sf.vx, sf.vy // CanInterface reports false
}
func (sf StructField) String() string { return fmt.Sprintf(".%s", sf.name) }
// Name is the field name.
func (sf StructField) Name() string { return sf.name }
// Index is the index of the field in the parent struct type.
// See [reflect.Type.Field].
func (sf StructField) Index() int { return sf.idx }
// SliceIndex is a [PathStep] that represents an index operation on
// a slice or array at some index [SliceIndex.Key].
type SliceIndex struct{ *sliceIndex }
type sliceIndex struct {
pathStep
xkey, ykey int
isSlice bool // False for reflect.Array
}
func (si SliceIndex) Type() reflect.Type { return si.typ }
func (si SliceIndex) Values() (vx, vy reflect.Value) { return si.vx, si.vy }
func (si SliceIndex) String() string {
switch {
case si.xkey == si.ykey:
return fmt.Sprintf("[%d]", si.xkey)
case si.ykey == -1:
// [5->?] means "I don't know where X[5] went"
return fmt.Sprintf("[%d->?]", si.xkey)
case si.xkey == -1:
// [?->3] means "I don't know where Y[3] came from"
return fmt.Sprintf("[?->%d]", si.ykey)
default:
// [5->3] means "X[5] moved to Y[3]"
return fmt.Sprintf("[%d->%d]", si.xkey, si.ykey)
}
}
// Key is the index key; it may return -1 if in a split state
func (si SliceIndex) Key() int {
if si.xkey != si.ykey {
return -1
}
return si.xkey
}
// SplitKeys are the indexes for indexing into slices in the
// x and y values, respectively. These indexes may differ due to the
// insertion or removal of an element in one of the slices, causing
// all of the indexes to be shifted. If an index is -1, then that
// indicates that the element does not exist in the associated slice.
//
// [SliceIndex.Key] is guaranteed to return -1 if and only if the indexes
// returned by SplitKeys are not the same. SplitKeys will never return -1 for
// both indexes.
func (si SliceIndex) SplitKeys() (ix, iy int) { return si.xkey, si.ykey }
// MapIndex is a [PathStep] that represents an index operation on a map at some index Key.
type MapIndex struct{ *mapIndex }
type mapIndex struct {
pathStep
key reflect.Value
}
func (mi MapIndex) Type() reflect.Type { return mi.typ }
func (mi MapIndex) Values() (vx, vy reflect.Value) { return mi.vx, mi.vy }
func (mi MapIndex) String() string { return fmt.Sprintf("[%#v]", mi.key) }
// Key is the value of the map key.
func (mi MapIndex) Key() reflect.Value { return mi.key }
// Indirect is a [PathStep] that represents pointer indirection on the parent type.
type Indirect struct{ *indirect }
type indirect struct {
pathStep
}
func (in Indirect) Type() reflect.Type { return in.typ }
func (in Indirect) Values() (vx, vy reflect.Value) { return in.vx, in.vy }
func (in Indirect) String() string { return "*" }
// TypeAssertion is a [PathStep] that represents a type assertion on an interface.
type TypeAssertion struct{ *typeAssertion }
type typeAssertion struct {
pathStep
}
func (ta TypeAssertion) Type() reflect.Type { return ta.typ }
func (ta TypeAssertion) Values() (vx, vy reflect.Value) { return ta.vx, ta.vy }
func (ta TypeAssertion) String() string { return fmt.Sprintf(".(%v)", value.TypeString(ta.typ, false)) }
// Transform is a [PathStep] that represents a transformation
// from the parent type to the current type.
type Transform struct{ *transform }
type transform struct {
pathStep
trans *transformer
}
func (tf Transform) Type() reflect.Type { return tf.typ }
func (tf Transform) Values() (vx, vy reflect.Value) { return tf.vx, tf.vy }
func (tf Transform) String() string { return fmt.Sprintf("%s()", tf.trans.name) }
// Name is the name of the [Transformer].
func (tf Transform) Name() string { return tf.trans.name }
// Func is the function pointer to the transformer function.
func (tf Transform) Func() reflect.Value { return tf.trans.fnc }
// Option returns the originally constructed [Transformer] option.
// The == operator can be used to detect the exact option used.
func (tf Transform) Option() Option { return tf.trans }
// pointerPath represents a dual-stack of pointers encountered when
// recursively traversing the x and y values. This data structure supports
// detection of cycles and determining whether the cycles are equal.
// In Go, cycles can occur via pointers, slices, and maps.
//
// The pointerPath uses a map to represent a stack; where descension into a
// pointer pushes the address onto the stack, and ascension from a pointer
// pops the address from the stack. Thus, when traversing into a pointer from
// reflect.Ptr, reflect.Slice element, or reflect.Map, we can detect cycles
// by checking whether the pointer has already been visited. The cycle detection
// uses a separate stack for the x and y values.
//
// If a cycle is detected we need to determine whether the two pointers
// should be considered equal. The definition of equality chosen by Equal
// requires two graphs to have the same structure. To determine this, both the
// x and y values must have a cycle where the previous pointers were also
// encountered together as a pair.
//
// Semantically, this is equivalent to augmenting Indirect, SliceIndex, and
// MapIndex with pointer information for the x and y values.
// Suppose px and py are two pointers to compare, we then search the
// Path for whether px was ever encountered in the Path history of x, and
// similarly so with py. If either side has a cycle, the comparison is only
// equal if both px and py have a cycle resulting from the same PathStep.
//
// Using a map as a stack is more performant as we can perform cycle detection
// in O(1) instead of O(N) where N is len(Path).
type pointerPath struct {
// mx is keyed by x pointers, where the value is the associated y pointer.
mx map[value.Pointer]value.Pointer
// my is keyed by y pointers, where the value is the associated x pointer.
my map[value.Pointer]value.Pointer
}
func (p *pointerPath) Init() {
p.mx = make(map[value.Pointer]value.Pointer)
p.my = make(map[value.Pointer]value.Pointer)
}
// Push indicates intent to descend into pointers vx and vy where
// visited reports whether either has been seen before. If visited before,
// equal reports whether both pointers were encountered together.
// Pop must be called if and only if the pointers were never visited.
//
// The pointers vx and vy must be a reflect.Ptr, reflect.Slice, or reflect.Map
// and be non-nil.
func (p pointerPath) Push(vx, vy reflect.Value) (equal, visited bool) {
px := value.PointerOf(vx)
py := value.PointerOf(vy)
_, ok1 := p.mx[px]
_, ok2 := p.my[py]
if ok1 || ok2 {
equal = p.mx[px] == py && p.my[py] == px // Pointers paired together
return equal, true
}
p.mx[px] = py
p.my[py] = px
return false, false
}
// Pop ascends from pointers vx and vy.
func (p pointerPath) Pop(vx, vy reflect.Value) {
delete(p.mx, value.PointerOf(vx))
delete(p.my, value.PointerOf(vy))
}
// isExported reports whether the identifier is exported.
func isExported(id string) bool {
r, _ := utf8.DecodeRuneInString(id)
return unicode.IsUpper(r)
}
// Copyright 2017, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cmp
// defaultReporter implements the reporter interface.
//
// As Equal serially calls the PushStep, Report, and PopStep methods, the
// defaultReporter constructs a tree-based representation of the compared value
// and the result of each comparison (see valueNode).
//
// When the String method is called, the FormatDiff method transforms the
// valueNode tree into a textNode tree, which is a tree-based representation
// of the textual output (see textNode).
//
// Lastly, the textNode.String method produces the final report as a string.
type defaultReporter struct {
root *valueNode
curr *valueNode
}
func (r *defaultReporter) PushStep(ps PathStep) {
r.curr = r.curr.PushStep(ps)
if r.root == nil {
r.root = r.curr
}
}
func (r *defaultReporter) Report(rs Result) {
r.curr.Report(rs)
}
func (r *defaultReporter) PopStep() {
r.curr = r.curr.PopStep()
}
// String provides a full report of the differences detected as a structured
// literal in pseudo-Go syntax. String may only be called after the entire tree
// has been traversed.
func (r *defaultReporter) String() string {
assert(r.root != nil && r.curr == nil)
if r.root.NumDiff == 0 {
return ""
}
ptrs := new(pointerReferences)
text := formatOptions{}.FormatDiff(r.root, ptrs)
resolveReferences(text)
return text.String()
}
func assert(ok bool) {
if !ok {
panic("assertion failure")
}
}
// Copyright 2019, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cmp
import (
"fmt"
"reflect"
)
// numContextRecords is the number of surrounding equal records to print.
const numContextRecords = 2
type diffMode byte
const (
diffUnknown diffMode = 0
diffIdentical diffMode = ' '
diffRemoved diffMode = '-'
diffInserted diffMode = '+'
)
type typeMode int
const (
// emitType always prints the type.
emitType typeMode = iota
// elideType never prints the type.
elideType
// autoType prints the type only for composite kinds
// (i.e., structs, slices, arrays, and maps).
autoType
)
type formatOptions struct {
// DiffMode controls the output mode of FormatDiff.
//
// If diffUnknown, then produce a diff of the x and y values.
// If diffIdentical, then emit values as if they were equal.
// If diffRemoved, then only emit x values (ignoring y values).
// If diffInserted, then only emit y values (ignoring x values).
DiffMode diffMode
// TypeMode controls whether to print the type for the current node.
//
// As a general rule of thumb, we always print the type of the next node
// after an interface, and always elide the type of the next node after
// a slice or map node.
TypeMode typeMode
// formatValueOptions are options specific to printing reflect.Values.
formatValueOptions
}
func (opts formatOptions) WithDiffMode(d diffMode) formatOptions {
opts.DiffMode = d
return opts
}
func (opts formatOptions) WithTypeMode(t typeMode) formatOptions {
opts.TypeMode = t
return opts
}
func (opts formatOptions) WithVerbosity(level int) formatOptions {
opts.VerbosityLevel = level
opts.LimitVerbosity = true
return opts
}
func (opts formatOptions) verbosity() uint {
switch {
case opts.VerbosityLevel < 0:
return 0
case opts.VerbosityLevel > 16:
return 16 // some reasonable maximum to avoid shift overflow
default:
return uint(opts.VerbosityLevel)
}
}
const maxVerbosityPreset = 6
// verbosityPreset modifies the verbosity settings given an index
// between 0 and maxVerbosityPreset, inclusive.
func verbosityPreset(opts formatOptions, i int) formatOptions {
opts.VerbosityLevel = int(opts.verbosity()) + 2*i
if i > 0 {
opts.AvoidStringer = true
}
if i >= maxVerbosityPreset {
opts.PrintAddresses = true
opts.QualifiedNames = true
}
return opts
}
// FormatDiff converts a valueNode tree into a textNode tree, where the later
// is a textual representation of the differences detected in the former.
func (opts formatOptions) FormatDiff(v *valueNode, ptrs *pointerReferences) (out textNode) {
if opts.DiffMode == diffIdentical {
opts = opts.WithVerbosity(1)
} else if opts.verbosity() < 3 {
opts = opts.WithVerbosity(3)
}
// Check whether we have specialized formatting for this node.
// This is not necessary, but helpful for producing more readable outputs.
if opts.CanFormatDiffSlice(v) {
return opts.FormatDiffSlice(v)
}
var parentKind reflect.Kind
if v.parent != nil && v.parent.TransformerName == "" {
parentKind = v.parent.Type.Kind()
}
// For leaf nodes, format the value based on the reflect.Values alone.
// As a special case, treat equal []byte as a leaf nodes.
isBytes := v.Type.Kind() == reflect.Slice && v.Type.Elem() == byteType
isEqualBytes := isBytes && v.NumDiff+v.NumIgnored+v.NumTransformed == 0
if v.MaxDepth == 0 || isEqualBytes {
switch opts.DiffMode {
case diffUnknown, diffIdentical:
// Format Equal.
if v.NumDiff == 0 {
outx := opts.FormatValue(v.ValueX, parentKind, ptrs)
outy := opts.FormatValue(v.ValueY, parentKind, ptrs)
if v.NumIgnored > 0 && v.NumSame == 0 {
return textEllipsis
} else if outx.Len() < outy.Len() {
return outx
} else {
return outy
}
}
// Format unequal.
assert(opts.DiffMode == diffUnknown)
var list textList
outx := opts.WithTypeMode(elideType).FormatValue(v.ValueX, parentKind, ptrs)
outy := opts.WithTypeMode(elideType).FormatValue(v.ValueY, parentKind, ptrs)
for i := 0; i <= maxVerbosityPreset && outx != nil && outy != nil && outx.Equal(outy); i++ {
opts2 := verbosityPreset(opts, i).WithTypeMode(elideType)
outx = opts2.FormatValue(v.ValueX, parentKind, ptrs)
outy = opts2.FormatValue(v.ValueY, parentKind, ptrs)
}
if outx != nil {
list = append(list, textRecord{Diff: '-', Value: outx})
}
if outy != nil {
list = append(list, textRecord{Diff: '+', Value: outy})
}
return opts.WithTypeMode(emitType).FormatType(v.Type, list)
case diffRemoved:
return opts.FormatValue(v.ValueX, parentKind, ptrs)
case diffInserted:
return opts.FormatValue(v.ValueY, parentKind, ptrs)
default:
panic("invalid diff mode")
}
}
// Register slice element to support cycle detection.
if parentKind == reflect.Slice {
ptrRefs := ptrs.PushPair(v.ValueX, v.ValueY, opts.DiffMode, true)
defer ptrs.Pop()
defer func() { out = wrapTrunkReferences(ptrRefs, out) }()
}
// Descend into the child value node.
if v.TransformerName != "" {
out := opts.WithTypeMode(emitType).FormatDiff(v.Value, ptrs)
out = &textWrap{Prefix: "Inverse(" + v.TransformerName + ", ", Value: out, Suffix: ")"}
return opts.FormatType(v.Type, out)
} else {
switch k := v.Type.Kind(); k {
case reflect.Struct, reflect.Array, reflect.Slice:
out = opts.formatDiffList(v.Records, k, ptrs)
out = opts.FormatType(v.Type, out)
case reflect.Map:
// Register map to support cycle detection.
ptrRefs := ptrs.PushPair(v.ValueX, v.ValueY, opts.DiffMode, false)
defer ptrs.Pop()
out = opts.formatDiffList(v.Records, k, ptrs)
out = wrapTrunkReferences(ptrRefs, out)
out = opts.FormatType(v.Type, out)
case reflect.Ptr:
// Register pointer to support cycle detection.
ptrRefs := ptrs.PushPair(v.ValueX, v.ValueY, opts.DiffMode, false)
defer ptrs.Pop()
out = opts.FormatDiff(v.Value, ptrs)
out = wrapTrunkReferences(ptrRefs, out)
out = &textWrap{Prefix: "&", Value: out}
case reflect.Interface:
out = opts.WithTypeMode(emitType).FormatDiff(v.Value, ptrs)
default:
panic(fmt.Sprintf("%v cannot have children", k))
}
return out
}
}
func (opts formatOptions) formatDiffList(recs []reportRecord, k reflect.Kind, ptrs *pointerReferences) textNode {
// Derive record name based on the data structure kind.
var name string
var formatKey func(reflect.Value) string
switch k {
case reflect.Struct:
name = "field"
opts = opts.WithTypeMode(autoType)
formatKey = func(v reflect.Value) string { return v.String() }
case reflect.Slice, reflect.Array:
name = "element"
opts = opts.WithTypeMode(elideType)
formatKey = func(reflect.Value) string { return "" }
case reflect.Map:
name = "entry"
opts = opts.WithTypeMode(elideType)
formatKey = func(v reflect.Value) string { return formatMapKey(v, false, ptrs) }
}
maxLen := -1
if opts.LimitVerbosity {
if opts.DiffMode == diffIdentical {
maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
} else {
maxLen = (1 << opts.verbosity()) << 1 // 2, 4, 8, 16, 32, 64, etc...
}
opts.VerbosityLevel--
}
// Handle unification.
switch opts.DiffMode {
case diffIdentical, diffRemoved, diffInserted:
var list textList
var deferredEllipsis bool // Add final "..." to indicate records were dropped
for _, r := range recs {
if len(list) == maxLen {
deferredEllipsis = true
break
}
// Elide struct fields that are zero value.
if k == reflect.Struct {
var isZero bool
switch opts.DiffMode {
case diffIdentical:
isZero = r.Value.ValueX.IsZero() || r.Value.ValueY.IsZero()
case diffRemoved:
isZero = r.Value.ValueX.IsZero()
case diffInserted:
isZero = r.Value.ValueY.IsZero()
}
if isZero {
continue
}
}
// Elide ignored nodes.
if r.Value.NumIgnored > 0 && r.Value.NumSame+r.Value.NumDiff == 0 {
deferredEllipsis = !(k == reflect.Slice || k == reflect.Array)
if !deferredEllipsis {
list.AppendEllipsis(diffStats{})
}
continue
}
if out := opts.FormatDiff(r.Value, ptrs); out != nil {
list = append(list, textRecord{Key: formatKey(r.Key), Value: out})
}
}
if deferredEllipsis {
list.AppendEllipsis(diffStats{})
}
return &textWrap{Prefix: "{", Value: list, Suffix: "}"}
case diffUnknown:
default:
panic("invalid diff mode")
}
// Handle differencing.
var numDiffs int
var list textList
var keys []reflect.Value // invariant: len(list) == len(keys)
groups := coalesceAdjacentRecords(name, recs)
maxGroup := diffStats{Name: name}
for i, ds := range groups {
if maxLen >= 0 && numDiffs >= maxLen {
maxGroup = maxGroup.Append(ds)
continue
}
// Handle equal records.
if ds.NumDiff() == 0 {
// Compute the number of leading and trailing records to print.
var numLo, numHi int
numEqual := ds.NumIgnored + ds.NumIdentical
for numLo < numContextRecords && numLo+numHi < numEqual && i != 0 {
if r := recs[numLo].Value; r.NumIgnored > 0 && r.NumSame+r.NumDiff == 0 {
break
}
numLo++
}
for numHi < numContextRecords && numLo+numHi < numEqual && i != len(groups)-1 {
if r := recs[numEqual-numHi-1].Value; r.NumIgnored > 0 && r.NumSame+r.NumDiff == 0 {
break
}
numHi++
}
if numEqual-(numLo+numHi) == 1 && ds.NumIgnored == 0 {
numHi++ // Avoid pointless coalescing of a single equal record
}
// Format the equal values.
for _, r := range recs[:numLo] {
out := opts.WithDiffMode(diffIdentical).FormatDiff(r.Value, ptrs)
list = append(list, textRecord{Key: formatKey(r.Key), Value: out})
keys = append(keys, r.Key)
}
if numEqual > numLo+numHi {
ds.NumIdentical -= numLo + numHi
list.AppendEllipsis(ds)
for len(keys) < len(list) {
keys = append(keys, reflect.Value{})
}
}
for _, r := range recs[numEqual-numHi : numEqual] {
out := opts.WithDiffMode(diffIdentical).FormatDiff(r.Value, ptrs)
list = append(list, textRecord{Key: formatKey(r.Key), Value: out})
keys = append(keys, r.Key)
}
recs = recs[numEqual:]
continue
}
// Handle unequal records.
for _, r := range recs[:ds.NumDiff()] {
switch {
case opts.CanFormatDiffSlice(r.Value):
out := opts.FormatDiffSlice(r.Value)
list = append(list, textRecord{Key: formatKey(r.Key), Value: out})
keys = append(keys, r.Key)
case r.Value.NumChildren == r.Value.MaxDepth:
outx := opts.WithDiffMode(diffRemoved).FormatDiff(r.Value, ptrs)
outy := opts.WithDiffMode(diffInserted).FormatDiff(r.Value, ptrs)
for i := 0; i <= maxVerbosityPreset && outx != nil && outy != nil && outx.Equal(outy); i++ {
opts2 := verbosityPreset(opts, i)
outx = opts2.WithDiffMode(diffRemoved).FormatDiff(r.Value, ptrs)
outy = opts2.WithDiffMode(diffInserted).FormatDiff(r.Value, ptrs)
}
if outx != nil {
list = append(list, textRecord{Diff: diffRemoved, Key: formatKey(r.Key), Value: outx})
keys = append(keys, r.Key)
}
if outy != nil {
list = append(list, textRecord{Diff: diffInserted, Key: formatKey(r.Key), Value: outy})
keys = append(keys, r.Key)
}
default:
out := opts.FormatDiff(r.Value, ptrs)
list = append(list, textRecord{Key: formatKey(r.Key), Value: out})
keys = append(keys, r.Key)
}
}
recs = recs[ds.NumDiff():]
numDiffs += ds.NumDiff()
}
if maxGroup.IsZero() {
assert(len(recs) == 0)
} else {
list.AppendEllipsis(maxGroup)
for len(keys) < len(list) {
keys = append(keys, reflect.Value{})
}
}
assert(len(list) == len(keys))
// For maps, the default formatting logic uses fmt.Stringer which may
// produce ambiguous output. Avoid calling String to disambiguate.
if k == reflect.Map {
var ambiguous bool
seenKeys := map[string]reflect.Value{}
for i, currKey := range keys {
if currKey.IsValid() {
strKey := list[i].Key
prevKey, seen := seenKeys[strKey]
if seen && prevKey.CanInterface() && currKey.CanInterface() {
ambiguous = prevKey.Interface() != currKey.Interface()
if ambiguous {
break
}
}
seenKeys[strKey] = currKey
}
}
if ambiguous {
for i, k := range keys {
if k.IsValid() {
list[i].Key = formatMapKey(k, true, ptrs)
}
}
}
}
return &textWrap{Prefix: "{", Value: list, Suffix: "}"}
}
// coalesceAdjacentRecords coalesces the list of records into groups of
// adjacent equal, or unequal counts.
func coalesceAdjacentRecords(name string, recs []reportRecord) (groups []diffStats) {
var prevCase int // Arbitrary index into which case last occurred
lastStats := func(i int) *diffStats {
if prevCase != i {
groups = append(groups, diffStats{Name: name})
prevCase = i
}
return &groups[len(groups)-1]
}
for _, r := range recs {
switch rv := r.Value; {
case rv.NumIgnored > 0 && rv.NumSame+rv.NumDiff == 0:
lastStats(1).NumIgnored++
case rv.NumDiff == 0:
lastStats(1).NumIdentical++
case rv.NumDiff > 0 && !rv.ValueY.IsValid():
lastStats(2).NumRemoved++
case rv.NumDiff > 0 && !rv.ValueX.IsValid():
lastStats(2).NumInserted++
default:
lastStats(2).NumModified++
}
}
return groups
}
// Copyright 2020, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cmp
import (
"fmt"
"reflect"
"strings"
"github.com/google/go-cmp/cmp/internal/flags"
"github.com/google/go-cmp/cmp/internal/value"
)
const (
pointerDelimPrefix = "⟪"
pointerDelimSuffix = "⟫"
)
// formatPointer prints the address of the pointer.
func formatPointer(p value.Pointer, withDelims bool) string {
v := p.Uintptr()
if flags.Deterministic {
v = 0xdeadf00f // Only used for stable testing purposes
}
if withDelims {
return pointerDelimPrefix + formatHex(uint64(v)) + pointerDelimSuffix
}
return formatHex(uint64(v))
}
// pointerReferences is a stack of pointers visited so far.
type pointerReferences [][2]value.Pointer
func (ps *pointerReferences) PushPair(vx, vy reflect.Value, d diffMode, deref bool) (pp [2]value.Pointer) {
if deref && vx.IsValid() {
vx = vx.Addr()
}
if deref && vy.IsValid() {
vy = vy.Addr()
}
switch d {
case diffUnknown, diffIdentical:
pp = [2]value.Pointer{value.PointerOf(vx), value.PointerOf(vy)}
case diffRemoved:
pp = [2]value.Pointer{value.PointerOf(vx), value.Pointer{}}
case diffInserted:
pp = [2]value.Pointer{value.Pointer{}, value.PointerOf(vy)}
}
*ps = append(*ps, pp)
return pp
}
func (ps *pointerReferences) Push(v reflect.Value) (p value.Pointer, seen bool) {
p = value.PointerOf(v)
for _, pp := range *ps {
if p == pp[0] || p == pp[1] {
return p, true
}
}
*ps = append(*ps, [2]value.Pointer{p, p})
return p, false
}
func (ps *pointerReferences) Pop() {
*ps = (*ps)[:len(*ps)-1]
}
// trunkReferences is metadata for a textNode indicating that the sub-tree
// represents the value for either pointer in a pair of references.
type trunkReferences struct{ pp [2]value.Pointer }
// trunkReference is metadata for a textNode indicating that the sub-tree
// represents the value for the given pointer reference.
type trunkReference struct{ p value.Pointer }
// leafReference is metadata for a textNode indicating that the value is
// truncated as it refers to another part of the tree (i.e., a trunk).
type leafReference struct{ p value.Pointer }
func wrapTrunkReferences(pp [2]value.Pointer, s textNode) textNode {
switch {
case pp[0].IsNil():
return &textWrap{Value: s, Metadata: trunkReference{pp[1]}}
case pp[1].IsNil():
return &textWrap{Value: s, Metadata: trunkReference{pp[0]}}
case pp[0] == pp[1]:
return &textWrap{Value: s, Metadata: trunkReference{pp[0]}}
default:
return &textWrap{Value: s, Metadata: trunkReferences{pp}}
}
}
func wrapTrunkReference(p value.Pointer, printAddress bool, s textNode) textNode {
var prefix string
if printAddress {
prefix = formatPointer(p, true)
}
return &textWrap{Prefix: prefix, Value: s, Metadata: trunkReference{p}}
}
func makeLeafReference(p value.Pointer, printAddress bool) textNode {
out := &textWrap{Prefix: "(", Value: textEllipsis, Suffix: ")"}
var prefix string
if printAddress {
prefix = formatPointer(p, true)
}
return &textWrap{Prefix: prefix, Value: out, Metadata: leafReference{p}}
}
// resolveReferences walks the textNode tree searching for any leaf reference
// metadata and resolves each against the corresponding trunk references.
// Since pointer addresses in memory are not particularly readable to the user,
// it replaces each pointer value with an arbitrary and unique reference ID.
func resolveReferences(s textNode) {
var walkNodes func(textNode, func(textNode))
walkNodes = func(s textNode, f func(textNode)) {
f(s)
switch s := s.(type) {
case *textWrap:
walkNodes(s.Value, f)
case textList:
for _, r := range s {
walkNodes(r.Value, f)
}
}
}
// Collect all trunks and leaves with reference metadata.
var trunks, leaves []*textWrap
walkNodes(s, func(s textNode) {
if s, ok := s.(*textWrap); ok {
switch s.Metadata.(type) {
case leafReference:
leaves = append(leaves, s)
case trunkReference, trunkReferences:
trunks = append(trunks, s)
}
}
})
// No leaf references to resolve.
if len(leaves) == 0 {
return
}
// Collect the set of all leaf references to resolve.
leafPtrs := make(map[value.Pointer]bool)
for _, leaf := range leaves {
leafPtrs[leaf.Metadata.(leafReference).p] = true
}
// Collect the set of trunk pointers that are always paired together.
// This allows us to assign a single ID to both pointers for brevity.
// If a pointer in a pair ever occurs by itself or as a different pair,
// then the pair is broken.
pairedTrunkPtrs := make(map[value.Pointer]value.Pointer)
unpair := func(p value.Pointer) {
if !pairedTrunkPtrs[p].IsNil() {
pairedTrunkPtrs[pairedTrunkPtrs[p]] = value.Pointer{} // invalidate other half
}
pairedTrunkPtrs[p] = value.Pointer{} // invalidate this half
}
for _, trunk := range trunks {
switch p := trunk.Metadata.(type) {
case trunkReference:
unpair(p.p) // standalone pointer cannot be part of a pair
case trunkReferences:
p0, ok0 := pairedTrunkPtrs[p.pp[0]]
p1, ok1 := pairedTrunkPtrs[p.pp[1]]
switch {
case !ok0 && !ok1:
// Register the newly seen pair.
pairedTrunkPtrs[p.pp[0]] = p.pp[1]
pairedTrunkPtrs[p.pp[1]] = p.pp[0]
case ok0 && ok1 && p0 == p.pp[1] && p1 == p.pp[0]:
// Exact pair already seen; do nothing.
default:
// Pair conflicts with some other pair; break all pairs.
unpair(p.pp[0])
unpair(p.pp[1])
}
}
}
// Correlate each pointer referenced by leaves to a unique identifier,
// and print the IDs for each trunk that matches those pointers.
var nextID uint
ptrIDs := make(map[value.Pointer]uint)
newID := func() uint {
id := nextID
nextID++
return id
}
for _, trunk := range trunks {
switch p := trunk.Metadata.(type) {
case trunkReference:
if print := leafPtrs[p.p]; print {
id, ok := ptrIDs[p.p]
if !ok {
id = newID()
ptrIDs[p.p] = id
}
trunk.Prefix = updateReferencePrefix(trunk.Prefix, formatReference(id))
}
case trunkReferences:
print0 := leafPtrs[p.pp[0]]
print1 := leafPtrs[p.pp[1]]
if print0 || print1 {
id0, ok0 := ptrIDs[p.pp[0]]
id1, ok1 := ptrIDs[p.pp[1]]
isPair := pairedTrunkPtrs[p.pp[0]] == p.pp[1] && pairedTrunkPtrs[p.pp[1]] == p.pp[0]
if isPair {
var id uint
assert(ok0 == ok1) // must be seen together or not at all
if ok0 {
assert(id0 == id1) // must have the same ID
id = id0
} else {
id = newID()
ptrIDs[p.pp[0]] = id
ptrIDs[p.pp[1]] = id
}
trunk.Prefix = updateReferencePrefix(trunk.Prefix, formatReference(id))
} else {
if print0 && !ok0 {
id0 = newID()
ptrIDs[p.pp[0]] = id0
}
if print1 && !ok1 {
id1 = newID()
ptrIDs[p.pp[1]] = id1
}
switch {
case print0 && print1:
trunk.Prefix = updateReferencePrefix(trunk.Prefix, formatReference(id0)+","+formatReference(id1))
case print0:
trunk.Prefix = updateReferencePrefix(trunk.Prefix, formatReference(id0))
case print1:
trunk.Prefix = updateReferencePrefix(trunk.Prefix, formatReference(id1))
}
}
}
}
}
// Update all leaf references with the unique identifier.
for _, leaf := range leaves {
if id, ok := ptrIDs[leaf.Metadata.(leafReference).p]; ok {
leaf.Prefix = updateReferencePrefix(leaf.Prefix, formatReference(id))
}
}
}
func formatReference(id uint) string {
return fmt.Sprintf("ref#%d", id)
}
func updateReferencePrefix(prefix, ref string) string {
if prefix == "" {
return pointerDelimPrefix + ref + pointerDelimSuffix
}
suffix := strings.TrimPrefix(prefix, pointerDelimPrefix)
return pointerDelimPrefix + ref + ": " + suffix
}
// Copyright 2019, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cmp
import (
"bytes"
"fmt"
"reflect"
"strconv"
"strings"
"unicode"
"unicode/utf8"
"github.com/google/go-cmp/cmp/internal/value"
)
var (
anyType = reflect.TypeOf((*interface{})(nil)).Elem()
stringType = reflect.TypeOf((*string)(nil)).Elem()
bytesType = reflect.TypeOf((*[]byte)(nil)).Elem()
byteType = reflect.TypeOf((*byte)(nil)).Elem()
)
type formatValueOptions struct {
// AvoidStringer controls whether to avoid calling custom stringer
// methods like error.Error or fmt.Stringer.String.
AvoidStringer bool
// PrintAddresses controls whether to print the address of all pointers,
// slice elements, and maps.
PrintAddresses bool
// QualifiedNames controls whether FormatType uses the fully qualified name
// (including the full package path as opposed to just the package name).
QualifiedNames bool
// VerbosityLevel controls the amount of output to produce.
// A higher value produces more output. A value of zero or lower produces
// no output (represented using an ellipsis).
// If LimitVerbosity is false, then the level is treated as infinite.
VerbosityLevel int
// LimitVerbosity specifies that formatting should respect VerbosityLevel.
LimitVerbosity bool
}
// FormatType prints the type as if it were wrapping s.
// This may return s as-is depending on the current type and TypeMode mode.
func (opts formatOptions) FormatType(t reflect.Type, s textNode) textNode {
// Check whether to emit the type or not.
switch opts.TypeMode {
case autoType:
switch t.Kind() {
case reflect.Struct, reflect.Slice, reflect.Array, reflect.Map:
if s.Equal(textNil) {
return s
}
default:
return s
}
if opts.DiffMode == diffIdentical {
return s // elide type for identical nodes
}
case elideType:
return s
}
// Determine the type label, applying special handling for unnamed types.
typeName := value.TypeString(t, opts.QualifiedNames)
if t.Name() == "" {
// According to Go grammar, certain type literals contain symbols that
// do not strongly bind to the next lexicographical token (e.g., *T).
switch t.Kind() {
case reflect.Chan, reflect.Func, reflect.Ptr:
typeName = "(" + typeName + ")"
}
}
return &textWrap{Prefix: typeName, Value: wrapParens(s)}
}
// wrapParens wraps s with a set of parenthesis, but avoids it if the
// wrapped node itself is already surrounded by a pair of parenthesis or braces.
// It handles unwrapping one level of pointer-reference nodes.
func wrapParens(s textNode) textNode {
var refNode *textWrap
if s2, ok := s.(*textWrap); ok {
// Unwrap a single pointer reference node.
switch s2.Metadata.(type) {
case leafReference, trunkReference, trunkReferences:
refNode = s2
if s3, ok := refNode.Value.(*textWrap); ok {
s2 = s3
}
}
// Already has delimiters that make parenthesis unnecessary.
hasParens := strings.HasPrefix(s2.Prefix, "(") && strings.HasSuffix(s2.Suffix, ")")
hasBraces := strings.HasPrefix(s2.Prefix, "{") && strings.HasSuffix(s2.Suffix, "}")
if hasParens || hasBraces {
return s
}
}
if refNode != nil {
refNode.Value = &textWrap{Prefix: "(", Value: refNode.Value, Suffix: ")"}
return s
}
return &textWrap{Prefix: "(", Value: s, Suffix: ")"}
}
// FormatValue prints the reflect.Value, taking extra care to avoid descending
// into pointers already in ptrs. As pointers are visited, ptrs is also updated.
func (opts formatOptions) FormatValue(v reflect.Value, parentKind reflect.Kind, ptrs *pointerReferences) (out textNode) {
if !v.IsValid() {
return nil
}
t := v.Type()
// Check slice element for cycles.
if parentKind == reflect.Slice {
ptrRef, visited := ptrs.Push(v.Addr())
if visited {
return makeLeafReference(ptrRef, false)
}
defer ptrs.Pop()
defer func() { out = wrapTrunkReference(ptrRef, false, out) }()
}
// Check whether there is an Error or String method to call.
if !opts.AvoidStringer && v.CanInterface() {
// Avoid calling Error or String methods on nil receivers since many
// implementations crash when doing so.
if (t.Kind() != reflect.Ptr && t.Kind() != reflect.Interface) || !v.IsNil() {
var prefix, strVal string
func() {
// Swallow and ignore any panics from String or Error.
defer func() { recover() }()
switch v := v.Interface().(type) {
case error:
strVal = v.Error()
prefix = "e"
case fmt.Stringer:
strVal = v.String()
prefix = "s"
}
}()
if prefix != "" {
return opts.formatString(prefix, strVal)
}
}
}
// Check whether to explicitly wrap the result with the type.
var skipType bool
defer func() {
if !skipType {
out = opts.FormatType(t, out)
}
}()
switch t.Kind() {
case reflect.Bool:
return textLine(fmt.Sprint(v.Bool()))
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return textLine(fmt.Sprint(v.Int()))
case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return textLine(fmt.Sprint(v.Uint()))
case reflect.Uint8:
if parentKind == reflect.Slice || parentKind == reflect.Array {
return textLine(formatHex(v.Uint()))
}
return textLine(fmt.Sprint(v.Uint()))
case reflect.Uintptr:
return textLine(formatHex(v.Uint()))
case reflect.Float32, reflect.Float64:
return textLine(fmt.Sprint(v.Float()))
case reflect.Complex64, reflect.Complex128:
return textLine(fmt.Sprint(v.Complex()))
case reflect.String:
return opts.formatString("", v.String())
case reflect.UnsafePointer, reflect.Chan, reflect.Func:
return textLine(formatPointer(value.PointerOf(v), true))
case reflect.Struct:
var list textList
v := makeAddressable(v) // needed for retrieveUnexportedField
maxLen := v.NumField()
if opts.LimitVerbosity {
maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
opts.VerbosityLevel--
}
for i := 0; i < v.NumField(); i++ {
vv := v.Field(i)
if vv.IsZero() {
continue // Elide fields with zero values
}
if len(list) == maxLen {
list.AppendEllipsis(diffStats{})
break
}
sf := t.Field(i)
if !isExported(sf.Name) {
vv = retrieveUnexportedField(v, sf, true)
}
s := opts.WithTypeMode(autoType).FormatValue(vv, t.Kind(), ptrs)
list = append(list, textRecord{Key: sf.Name, Value: s})
}
return &textWrap{Prefix: "{", Value: list, Suffix: "}"}
case reflect.Slice:
if v.IsNil() {
return textNil
}
// Check whether this is a []byte of text data.
if t.Elem() == byteType {
b := v.Bytes()
isPrintSpace := func(r rune) bool { return unicode.IsPrint(r) || unicode.IsSpace(r) }
if len(b) > 0 && utf8.Valid(b) && len(bytes.TrimFunc(b, isPrintSpace)) == 0 {
out = opts.formatString("", string(b))
skipType = true
return opts.FormatType(t, out)
}
}
fallthrough
case reflect.Array:
maxLen := v.Len()
if opts.LimitVerbosity {
maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
opts.VerbosityLevel--
}
var list textList
for i := 0; i < v.Len(); i++ {
if len(list) == maxLen {
list.AppendEllipsis(diffStats{})
break
}
s := opts.WithTypeMode(elideType).FormatValue(v.Index(i), t.Kind(), ptrs)
list = append(list, textRecord{Value: s})
}
out = &textWrap{Prefix: "{", Value: list, Suffix: "}"}
if t.Kind() == reflect.Slice && opts.PrintAddresses {
header := fmt.Sprintf("ptr:%v, len:%d, cap:%d", formatPointer(value.PointerOf(v), false), v.Len(), v.Cap())
out = &textWrap{Prefix: pointerDelimPrefix + header + pointerDelimSuffix, Value: out}
}
return out
case reflect.Map:
if v.IsNil() {
return textNil
}
// Check pointer for cycles.
ptrRef, visited := ptrs.Push(v)
if visited {
return makeLeafReference(ptrRef, opts.PrintAddresses)
}
defer ptrs.Pop()
maxLen := v.Len()
if opts.LimitVerbosity {
maxLen = ((1 << opts.verbosity()) >> 1) << 2 // 0, 4, 8, 16, 32, etc...
opts.VerbosityLevel--
}
var list textList
for _, k := range value.SortKeys(v.MapKeys()) {
if len(list) == maxLen {
list.AppendEllipsis(diffStats{})
break
}
sk := formatMapKey(k, false, ptrs)
sv := opts.WithTypeMode(elideType).FormatValue(v.MapIndex(k), t.Kind(), ptrs)
list = append(list, textRecord{Key: sk, Value: sv})
}
out = &textWrap{Prefix: "{", Value: list, Suffix: "}"}
out = wrapTrunkReference(ptrRef, opts.PrintAddresses, out)
return out
case reflect.Ptr:
if v.IsNil() {
return textNil
}
// Check pointer for cycles.
ptrRef, visited := ptrs.Push(v)
if visited {
out = makeLeafReference(ptrRef, opts.PrintAddresses)
return &textWrap{Prefix: "&", Value: out}
}
defer ptrs.Pop()
// Skip the name only if this is an unnamed pointer type.
// Otherwise taking the address of a value does not reproduce
// the named pointer type.
if v.Type().Name() == "" {
skipType = true // Let the underlying value print the type instead
}
out = opts.FormatValue(v.Elem(), t.Kind(), ptrs)
out = wrapTrunkReference(ptrRef, opts.PrintAddresses, out)
out = &textWrap{Prefix: "&", Value: out}
return out
case reflect.Interface:
if v.IsNil() {
return textNil
}
// Interfaces accept different concrete types,
// so configure the underlying value to explicitly print the type.
return opts.WithTypeMode(emitType).FormatValue(v.Elem(), t.Kind(), ptrs)
default:
panic(fmt.Sprintf("%v kind not handled", v.Kind()))
}
}
func (opts formatOptions) formatString(prefix, s string) textNode {
maxLen := len(s)
maxLines := strings.Count(s, "\n") + 1
if opts.LimitVerbosity {
maxLen = (1 << opts.verbosity()) << 5 // 32, 64, 128, 256, etc...
maxLines = (1 << opts.verbosity()) << 2 // 4, 8, 16, 32, 64, etc...
}
// For multiline strings, use the triple-quote syntax,
// but only use it when printing removed or inserted nodes since
// we only want the extra verbosity for those cases.
lines := strings.Split(strings.TrimSuffix(s, "\n"), "\n")
isTripleQuoted := len(lines) >= 4 && (opts.DiffMode == '-' || opts.DiffMode == '+')
for i := 0; i < len(lines) && isTripleQuoted; i++ {
lines[i] = strings.TrimPrefix(strings.TrimSuffix(lines[i], "\r"), "\r") // trim leading/trailing carriage returns for legacy Windows endline support
isPrintable := func(r rune) bool {
return unicode.IsPrint(r) || r == '\t' // specially treat tab as printable
}
line := lines[i]
isTripleQuoted = !strings.HasPrefix(strings.TrimPrefix(line, prefix), `"""`) && !strings.HasPrefix(line, "...") && strings.TrimFunc(line, isPrintable) == "" && len(line) <= maxLen
}
if isTripleQuoted {
var list textList
list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(prefix + `"""`), ElideComma: true})
for i, line := range lines {
if numElided := len(lines) - i; i == maxLines-1 && numElided > 1 {
comment := commentString(fmt.Sprintf("%d elided lines", numElided))
list = append(list, textRecord{Diff: opts.DiffMode, Value: textEllipsis, ElideComma: true, Comment: comment})
break
}
list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(line), ElideComma: true})
}
list = append(list, textRecord{Diff: opts.DiffMode, Value: textLine(prefix + `"""`), ElideComma: true})
return &textWrap{Prefix: "(", Value: list, Suffix: ")"}
}
// Format the string as a single-line quoted string.
if len(s) > maxLen+len(textEllipsis) {
return textLine(prefix + formatString(s[:maxLen]) + string(textEllipsis))
}
return textLine(prefix + formatString(s))
}
// formatMapKey formats v as if it were a map key.
// The result is guaranteed to be a single line.
func formatMapKey(v reflect.Value, disambiguate bool, ptrs *pointerReferences) string {
var opts formatOptions
opts.DiffMode = diffIdentical
opts.TypeMode = elideType
opts.PrintAddresses = disambiguate
opts.AvoidStringer = disambiguate
opts.QualifiedNames = disambiguate
opts.VerbosityLevel = maxVerbosityPreset
opts.LimitVerbosity = true
s := opts.FormatValue(v, reflect.Map, ptrs).String()
return strings.TrimSpace(s)
}
// formatString prints s as a double-quoted or backtick-quoted string.
func formatString(s string) string {
// Use quoted string if it the same length as a raw string literal.
// Otherwise, attempt to use the raw string form.
qs := strconv.Quote(s)
if len(qs) == 1+len(s)+1 {
return qs
}
// Disallow newlines to ensure output is a single line.
// Only allow printable runes for readability purposes.
rawInvalid := func(r rune) bool {
return r == '`' || r == '\n' || !(unicode.IsPrint(r) || r == '\t')
}
if utf8.ValidString(s) && strings.IndexFunc(s, rawInvalid) < 0 {
return "`" + s + "`"
}
return qs
}
// formatHex prints u as a hexadecimal integer in Go notation.
func formatHex(u uint64) string {
var f string
switch {
case u <= 0xff:
f = "0x%02x"
case u <= 0xffff:
f = "0x%04x"
case u <= 0xffffff:
f = "0x%06x"
case u <= 0xffffffff:
f = "0x%08x"
case u <= 0xffffffffff:
f = "0x%010x"
case u <= 0xffffffffffff:
f = "0x%012x"
case u <= 0xffffffffffffff:
f = "0x%014x"
case u <= 0xffffffffffffffff:
f = "0x%016x"
}
return fmt.Sprintf(f, u)
}
// Copyright 2019, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cmp
import (
"bytes"
"fmt"
"math"
"reflect"
"strconv"
"strings"
"unicode"
"unicode/utf8"
"github.com/google/go-cmp/cmp/internal/diff"
)
// CanFormatDiffSlice reports whether we support custom formatting for nodes
// that are slices of primitive kinds or strings.
func (opts formatOptions) CanFormatDiffSlice(v *valueNode) bool {
switch {
case opts.DiffMode != diffUnknown:
return false // Must be formatting in diff mode
case v.NumDiff == 0:
return false // No differences detected
case !v.ValueX.IsValid() || !v.ValueY.IsValid():
return false // Both values must be valid
case v.NumIgnored > 0:
return false // Some ignore option was used
case v.NumTransformed > 0:
return false // Some transform option was used
case v.NumCompared > 1:
return false // More than one comparison was used
case v.NumCompared == 1 && v.Type.Name() != "":
// The need for cmp to check applicability of options on every element
// in a slice is a significant performance detriment for large []byte.
// The workaround is to specify Comparer(bytes.Equal),
// which enables cmp to compare []byte more efficiently.
// If they differ, we still want to provide batched diffing.
// The logic disallows named types since they tend to have their own
// String method, with nicer formatting than what this provides.
return false
}
// Check whether this is an interface with the same concrete types.
t := v.Type
vx, vy := v.ValueX, v.ValueY
if t.Kind() == reflect.Interface && !vx.IsNil() && !vy.IsNil() && vx.Elem().Type() == vy.Elem().Type() {
vx, vy = vx.Elem(), vy.Elem()
t = vx.Type()
}
// Check whether we provide specialized diffing for this type.
switch t.Kind() {
case reflect.String:
case reflect.Array, reflect.Slice:
// Only slices of primitive types have specialized handling.
switch t.Elem().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr,
reflect.Bool, reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
default:
return false
}
// Both slice values have to be non-empty.
if t.Kind() == reflect.Slice && (vx.Len() == 0 || vy.Len() == 0) {
return false
}
// If a sufficient number of elements already differ,
// use specialized formatting even if length requirement is not met.
if v.NumDiff > v.NumSame {
return true
}
default:
return false
}
// Use specialized string diffing for longer slices or strings.
const minLength = 32
return vx.Len() >= minLength && vy.Len() >= minLength
}
// FormatDiffSlice prints a diff for the slices (or strings) represented by v.
// This provides custom-tailored logic to make printing of differences in
// textual strings and slices of primitive kinds more readable.
func (opts formatOptions) FormatDiffSlice(v *valueNode) textNode {
assert(opts.DiffMode == diffUnknown)
t, vx, vy := v.Type, v.ValueX, v.ValueY
if t.Kind() == reflect.Interface {
vx, vy = vx.Elem(), vy.Elem()
t = vx.Type()
opts = opts.WithTypeMode(emitType)
}
// Auto-detect the type of the data.
var sx, sy string
var ssx, ssy []string
var isString, isMostlyText, isPureLinedText, isBinary bool
switch {
case t.Kind() == reflect.String:
sx, sy = vx.String(), vy.String()
isString = true
case t.Kind() == reflect.Slice && t.Elem() == byteType:
sx, sy = string(vx.Bytes()), string(vy.Bytes())
isString = true
case t.Kind() == reflect.Array:
// Arrays need to be addressable for slice operations to work.
vx2, vy2 := reflect.New(t).Elem(), reflect.New(t).Elem()
vx2.Set(vx)
vy2.Set(vy)
vx, vy = vx2, vy2
}
if isString {
var numTotalRunes, numValidRunes, numLines, lastLineIdx, maxLineLen int
for i, r := range sx + sy {
numTotalRunes++
if (unicode.IsPrint(r) || unicode.IsSpace(r)) && r != utf8.RuneError {
numValidRunes++
}
if r == '\n' {
if maxLineLen < i-lastLineIdx {
maxLineLen = i - lastLineIdx
}
lastLineIdx = i + 1
numLines++
}
}
isPureText := numValidRunes == numTotalRunes
isMostlyText = float64(numValidRunes) > math.Floor(0.90*float64(numTotalRunes))
isPureLinedText = isPureText && numLines >= 4 && maxLineLen <= 1024
isBinary = !isMostlyText
// Avoid diffing by lines if it produces a significantly more complex
// edit script than diffing by bytes.
if isPureLinedText {
ssx = strings.Split(sx, "\n")
ssy = strings.Split(sy, "\n")
esLines := diff.Difference(len(ssx), len(ssy), func(ix, iy int) diff.Result {
return diff.BoolResult(ssx[ix] == ssy[iy])
})
esBytes := diff.Difference(len(sx), len(sy), func(ix, iy int) diff.Result {
return diff.BoolResult(sx[ix] == sy[iy])
})
efficiencyLines := float64(esLines.Dist()) / float64(len(esLines))
efficiencyBytes := float64(esBytes.Dist()) / float64(len(esBytes))
quotedLength := len(strconv.Quote(sx + sy))
unquotedLength := len(sx) + len(sy)
escapeExpansionRatio := float64(quotedLength) / float64(unquotedLength)
isPureLinedText = efficiencyLines < 4*efficiencyBytes || escapeExpansionRatio > 1.1
}
}
// Format the string into printable records.
var list textList
var delim string
switch {
// If the text appears to be multi-lined text,
// then perform differencing across individual lines.
case isPureLinedText:
list = opts.formatDiffSlice(
reflect.ValueOf(ssx), reflect.ValueOf(ssy), 1, "line",
func(v reflect.Value, d diffMode) textRecord {
s := formatString(v.Index(0).String())
return textRecord{Diff: d, Value: textLine(s)}
},
)
delim = "\n"
// If possible, use a custom triple-quote (""") syntax for printing
// differences in a string literal. This format is more readable,
// but has edge-cases where differences are visually indistinguishable.
// This format is avoided under the following conditions:
// - A line starts with `"""`
// - A line starts with "..."
// - A line contains non-printable characters
// - Adjacent different lines differ only by whitespace
//
// For example:
//
// """
// ... // 3 identical lines
// foo
// bar
// - baz
// + BAZ
// """
isTripleQuoted := true
prevRemoveLines := map[string]bool{}
prevInsertLines := map[string]bool{}
var list2 textList
list2 = append(list2, textRecord{Value: textLine(`"""`), ElideComma: true})
for _, r := range list {
if !r.Value.Equal(textEllipsis) {
line, _ := strconv.Unquote(string(r.Value.(textLine)))
line = strings.TrimPrefix(strings.TrimSuffix(line, "\r"), "\r") // trim leading/trailing carriage returns for legacy Windows endline support
normLine := strings.Map(func(r rune) rune {
if unicode.IsSpace(r) {
return -1 // drop whitespace to avoid visually indistinguishable output
}
return r
}, line)
isPrintable := func(r rune) bool {
return unicode.IsPrint(r) || r == '\t' // specially treat tab as printable
}
isTripleQuoted = !strings.HasPrefix(line, `"""`) && !strings.HasPrefix(line, "...") && strings.TrimFunc(line, isPrintable) == ""
switch r.Diff {
case diffRemoved:
isTripleQuoted = isTripleQuoted && !prevInsertLines[normLine]
prevRemoveLines[normLine] = true
case diffInserted:
isTripleQuoted = isTripleQuoted && !prevRemoveLines[normLine]
prevInsertLines[normLine] = true
}
if !isTripleQuoted {
break
}
r.Value = textLine(line)
r.ElideComma = true
}
if !(r.Diff == diffRemoved || r.Diff == diffInserted) { // start a new non-adjacent difference group
prevRemoveLines = map[string]bool{}
prevInsertLines = map[string]bool{}
}
list2 = append(list2, r)
}
if r := list2[len(list2)-1]; r.Diff == diffIdentical && len(r.Value.(textLine)) == 0 {
list2 = list2[:len(list2)-1] // elide single empty line at the end
}
list2 = append(list2, textRecord{Value: textLine(`"""`), ElideComma: true})
if isTripleQuoted {
var out textNode = &textWrap{Prefix: "(", Value: list2, Suffix: ")"}
switch t.Kind() {
case reflect.String:
if t != stringType {
out = opts.FormatType(t, out)
}
case reflect.Slice:
// Always emit type for slices since the triple-quote syntax
// looks like a string (not a slice).
opts = opts.WithTypeMode(emitType)
out = opts.FormatType(t, out)
}
return out
}
// If the text appears to be single-lined text,
// then perform differencing in approximately fixed-sized chunks.
// The output is printed as quoted strings.
case isMostlyText:
list = opts.formatDiffSlice(
reflect.ValueOf(sx), reflect.ValueOf(sy), 64, "byte",
func(v reflect.Value, d diffMode) textRecord {
s := formatString(v.String())
return textRecord{Diff: d, Value: textLine(s)}
},
)
// If the text appears to be binary data,
// then perform differencing in approximately fixed-sized chunks.
// The output is inspired by hexdump.
case isBinary:
list = opts.formatDiffSlice(
reflect.ValueOf(sx), reflect.ValueOf(sy), 16, "byte",
func(v reflect.Value, d diffMode) textRecord {
var ss []string
for i := 0; i < v.Len(); i++ {
ss = append(ss, formatHex(v.Index(i).Uint()))
}
s := strings.Join(ss, ", ")
comment := commentString(fmt.Sprintf("%c|%v|", d, formatASCII(v.String())))
return textRecord{Diff: d, Value: textLine(s), Comment: comment}
},
)
// For all other slices of primitive types,
// then perform differencing in approximately fixed-sized chunks.
// The size of each chunk depends on the width of the element kind.
default:
var chunkSize int
if t.Elem().Kind() == reflect.Bool {
chunkSize = 16
} else {
switch t.Elem().Bits() {
case 8:
chunkSize = 16
case 16:
chunkSize = 12
case 32:
chunkSize = 8
default:
chunkSize = 8
}
}
list = opts.formatDiffSlice(
vx, vy, chunkSize, t.Elem().Kind().String(),
func(v reflect.Value, d diffMode) textRecord {
var ss []string
for i := 0; i < v.Len(); i++ {
switch t.Elem().Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
ss = append(ss, fmt.Sprint(v.Index(i).Int()))
case reflect.Uint, reflect.Uint16, reflect.Uint32, reflect.Uint64:
ss = append(ss, fmt.Sprint(v.Index(i).Uint()))
case reflect.Uint8, reflect.Uintptr:
ss = append(ss, formatHex(v.Index(i).Uint()))
case reflect.Bool, reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128:
ss = append(ss, fmt.Sprint(v.Index(i).Interface()))
}
}
s := strings.Join(ss, ", ")
return textRecord{Diff: d, Value: textLine(s)}
},
)
}
// Wrap the output with appropriate type information.
var out textNode = &textWrap{Prefix: "{", Value: list, Suffix: "}"}
if !isMostlyText {
// The "{...}" byte-sequence literal is not valid Go syntax for strings.
// Emit the type for extra clarity (e.g. "string{...}").
if t.Kind() == reflect.String {
opts = opts.WithTypeMode(emitType)
}
return opts.FormatType(t, out)
}
switch t.Kind() {
case reflect.String:
out = &textWrap{Prefix: "strings.Join(", Value: out, Suffix: fmt.Sprintf(", %q)", delim)}
if t != stringType {
out = opts.FormatType(t, out)
}
case reflect.Slice:
out = &textWrap{Prefix: "bytes.Join(", Value: out, Suffix: fmt.Sprintf(", %q)", delim)}
if t != bytesType {
out = opts.FormatType(t, out)
}
}
return out
}
// formatASCII formats s as an ASCII string.
// This is useful for printing binary strings in a semi-legible way.
func formatASCII(s string) string {
b := bytes.Repeat([]byte{'.'}, len(s))
for i := 0; i < len(s); i++ {
if ' ' <= s[i] && s[i] <= '~' {
b[i] = s[i]
}
}
return string(b)
}
func (opts formatOptions) formatDiffSlice(
vx, vy reflect.Value, chunkSize int, name string,
makeRec func(reflect.Value, diffMode) textRecord,
) (list textList) {
eq := func(ix, iy int) bool {
return vx.Index(ix).Interface() == vy.Index(iy).Interface()
}
es := diff.Difference(vx.Len(), vy.Len(), func(ix, iy int) diff.Result {
return diff.BoolResult(eq(ix, iy))
})
appendChunks := func(v reflect.Value, d diffMode) int {
n0 := v.Len()
for v.Len() > 0 {
n := chunkSize
if n > v.Len() {
n = v.Len()
}
list = append(list, makeRec(v.Slice(0, n), d))
v = v.Slice(n, v.Len())
}
return n0 - v.Len()
}
var numDiffs int
maxLen := -1
if opts.LimitVerbosity {
maxLen = (1 << opts.verbosity()) << 2 // 4, 8, 16, 32, 64, etc...
opts.VerbosityLevel--
}
groups := coalesceAdjacentEdits(name, es)
groups = coalesceInterveningIdentical(groups, chunkSize/4)
groups = cleanupSurroundingIdentical(groups, eq)
maxGroup := diffStats{Name: name}
for i, ds := range groups {
if maxLen >= 0 && numDiffs >= maxLen {
maxGroup = maxGroup.Append(ds)
continue
}
// Print equal.
if ds.NumDiff() == 0 {
// Compute the number of leading and trailing equal bytes to print.
var numLo, numHi int
numEqual := ds.NumIgnored + ds.NumIdentical
for numLo < chunkSize*numContextRecords && numLo+numHi < numEqual && i != 0 {
numLo++
}
for numHi < chunkSize*numContextRecords && numLo+numHi < numEqual && i != len(groups)-1 {
numHi++
}
if numEqual-(numLo+numHi) <= chunkSize && ds.NumIgnored == 0 {
numHi = numEqual - numLo // Avoid pointless coalescing of single equal row
}
// Print the equal bytes.
appendChunks(vx.Slice(0, numLo), diffIdentical)
if numEqual > numLo+numHi {
ds.NumIdentical -= numLo + numHi
list.AppendEllipsis(ds)
}
appendChunks(vx.Slice(numEqual-numHi, numEqual), diffIdentical)
vx = vx.Slice(numEqual, vx.Len())
vy = vy.Slice(numEqual, vy.Len())
continue
}
// Print unequal.
len0 := len(list)
nx := appendChunks(vx.Slice(0, ds.NumIdentical+ds.NumRemoved+ds.NumModified), diffRemoved)
vx = vx.Slice(nx, vx.Len())
ny := appendChunks(vy.Slice(0, ds.NumIdentical+ds.NumInserted+ds.NumModified), diffInserted)
vy = vy.Slice(ny, vy.Len())
numDiffs += len(list) - len0
}
if maxGroup.IsZero() {
assert(vx.Len() == 0 && vy.Len() == 0)
} else {
list.AppendEllipsis(maxGroup)
}
return list
}
// coalesceAdjacentEdits coalesces the list of edits into groups of adjacent
// equal or unequal counts.
//
// Example:
//
// Input: "..XXY...Y"
// Output: [
// {NumIdentical: 2},
// {NumRemoved: 2, NumInserted 1},
// {NumIdentical: 3},
// {NumInserted: 1},
// ]
func coalesceAdjacentEdits(name string, es diff.EditScript) (groups []diffStats) {
var prevMode byte
lastStats := func(mode byte) *diffStats {
if prevMode != mode {
groups = append(groups, diffStats{Name: name})
prevMode = mode
}
return &groups[len(groups)-1]
}
for _, e := range es {
switch e {
case diff.Identity:
lastStats('=').NumIdentical++
case diff.UniqueX:
lastStats('!').NumRemoved++
case diff.UniqueY:
lastStats('!').NumInserted++
case diff.Modified:
lastStats('!').NumModified++
}
}
return groups
}
// coalesceInterveningIdentical coalesces sufficiently short (<= windowSize)
// equal groups into adjacent unequal groups that currently result in a
// dual inserted/removed printout. This acts as a high-pass filter to smooth
// out high-frequency changes within the windowSize.
//
// Example:
//
// WindowSize: 16,
// Input: [
// {NumIdentical: 61}, // group 0
// {NumRemoved: 3, NumInserted: 1}, // group 1
// {NumIdentical: 6}, // ├── coalesce
// {NumInserted: 2}, // ├── coalesce
// {NumIdentical: 1}, // ├── coalesce
// {NumRemoved: 9}, // └── coalesce
// {NumIdentical: 64}, // group 2
// {NumRemoved: 3, NumInserted: 1}, // group 3
// {NumIdentical: 6}, // ├── coalesce
// {NumInserted: 2}, // ├── coalesce
// {NumIdentical: 1}, // ├── coalesce
// {NumRemoved: 7}, // ├── coalesce
// {NumIdentical: 1}, // ├── coalesce
// {NumRemoved: 2}, // └── coalesce
// {NumIdentical: 63}, // group 4
// ]
// Output: [
// {NumIdentical: 61},
// {NumIdentical: 7, NumRemoved: 12, NumInserted: 3},
// {NumIdentical: 64},
// {NumIdentical: 8, NumRemoved: 12, NumInserted: 3},
// {NumIdentical: 63},
// ]
func coalesceInterveningIdentical(groups []diffStats, windowSize int) []diffStats {
groups, groupsOrig := groups[:0], groups
for i, ds := range groupsOrig {
if len(groups) >= 2 && ds.NumDiff() > 0 {
prev := &groups[len(groups)-2] // Unequal group
curr := &groups[len(groups)-1] // Equal group
next := &groupsOrig[i] // Unequal group
hadX, hadY := prev.NumRemoved > 0, prev.NumInserted > 0
hasX, hasY := next.NumRemoved > 0, next.NumInserted > 0
if ((hadX || hasX) && (hadY || hasY)) && curr.NumIdentical <= windowSize {
*prev = prev.Append(*curr).Append(*next)
groups = groups[:len(groups)-1] // Truncate off equal group
continue
}
}
groups = append(groups, ds)
}
return groups
}
// cleanupSurroundingIdentical scans through all unequal groups, and
// moves any leading sequence of equal elements to the preceding equal group and
// moves and trailing sequence of equal elements to the succeeding equal group.
//
// This is necessary since coalesceInterveningIdentical may coalesce edit groups
// together such that leading/trailing spans of equal elements becomes possible.
// Note that this can occur even with an optimal diffing algorithm.
//
// Example:
//
// Input: [
// {NumIdentical: 61},
// {NumIdentical: 1 , NumRemoved: 11, NumInserted: 2}, // assume 3 leading identical elements
// {NumIdentical: 67},
// {NumIdentical: 7, NumRemoved: 12, NumInserted: 3}, // assume 10 trailing identical elements
// {NumIdentical: 54},
// ]
// Output: [
// {NumIdentical: 64}, // incremented by 3
// {NumRemoved: 9},
// {NumIdentical: 67},
// {NumRemoved: 9},
// {NumIdentical: 64}, // incremented by 10
// ]
func cleanupSurroundingIdentical(groups []diffStats, eq func(i, j int) bool) []diffStats {
var ix, iy int // indexes into sequence x and y
for i, ds := range groups {
// Handle equal group.
if ds.NumDiff() == 0 {
ix += ds.NumIdentical
iy += ds.NumIdentical
continue
}
// Handle unequal group.
nx := ds.NumIdentical + ds.NumRemoved + ds.NumModified
ny := ds.NumIdentical + ds.NumInserted + ds.NumModified
var numLeadingIdentical, numTrailingIdentical int
for j := 0; j < nx && j < ny && eq(ix+j, iy+j); j++ {
numLeadingIdentical++
}
for j := 0; j < nx && j < ny && eq(ix+nx-1-j, iy+ny-1-j); j++ {
numTrailingIdentical++
}
if numIdentical := numLeadingIdentical + numTrailingIdentical; numIdentical > 0 {
if numLeadingIdentical > 0 {
// Remove leading identical span from this group and
// insert it into the preceding group.
if i-1 >= 0 {
groups[i-1].NumIdentical += numLeadingIdentical
} else {
// No preceding group exists, so prepend a new group,
// but do so after we finish iterating over all groups.
defer func() {
groups = append([]diffStats{{Name: groups[0].Name, NumIdentical: numLeadingIdentical}}, groups...)
}()
}
// Increment indexes since the preceding group would have handled this.
ix += numLeadingIdentical
iy += numLeadingIdentical
}
if numTrailingIdentical > 0 {
// Remove trailing identical span from this group and
// insert it into the succeeding group.
if i+1 < len(groups) {
groups[i+1].NumIdentical += numTrailingIdentical
} else {
// No succeeding group exists, so append a new group,
// but do so after we finish iterating over all groups.
defer func() {
groups = append(groups, diffStats{Name: groups[len(groups)-1].Name, NumIdentical: numTrailingIdentical})
}()
}
// Do not increment indexes since the succeeding group will handle this.
}
// Update this group since some identical elements were removed.
nx -= numIdentical
ny -= numIdentical
groups[i] = diffStats{Name: ds.Name, NumRemoved: nx, NumInserted: ny}
}
ix += nx
iy += ny
}
return groups
}
// Copyright 2019, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cmp
import (
"bytes"
"fmt"
"math/rand"
"strings"
"time"
"unicode/utf8"
"github.com/google/go-cmp/cmp/internal/flags"
)
var randBool = rand.New(rand.NewSource(time.Now().Unix())).Intn(2) == 0
const maxColumnLength = 80
type indentMode int
func (n indentMode) appendIndent(b []byte, d diffMode) []byte {
// The output of Diff is documented as being unstable to provide future
// flexibility in changing the output for more humanly readable reports.
// This logic intentionally introduces instability to the exact output
// so that users can detect accidental reliance on stability early on,
// rather than much later when an actual change to the format occurs.
if flags.Deterministic || randBool {
// Use regular spaces (U+0020).
switch d {
case diffUnknown, diffIdentical:
b = append(b, " "...)
case diffRemoved:
b = append(b, "- "...)
case diffInserted:
b = append(b, "+ "...)
}
} else {
// Use non-breaking spaces (U+00a0).
switch d {
case diffUnknown, diffIdentical:
b = append(b, " "...)
case diffRemoved:
b = append(b, "- "...)
case diffInserted:
b = append(b, "+ "...)
}
}
return repeatCount(n).appendChar(b, '\t')
}
type repeatCount int
func (n repeatCount) appendChar(b []byte, c byte) []byte {
for ; n > 0; n-- {
b = append(b, c)
}
return b
}
// textNode is a simplified tree-based representation of structured text.
// Possible node types are textWrap, textList, or textLine.
type textNode interface {
// Len reports the length in bytes of a single-line version of the tree.
// Nested textRecord.Diff and textRecord.Comment fields are ignored.
Len() int
// Equal reports whether the two trees are structurally identical.
// Nested textRecord.Diff and textRecord.Comment fields are compared.
Equal(textNode) bool
// String returns the string representation of the text tree.
// It is not guaranteed that len(x.String()) == x.Len(),
// nor that x.String() == y.String() implies that x.Equal(y).
String() string
// formatCompactTo formats the contents of the tree as a single-line string
// to the provided buffer. Any nested textRecord.Diff and textRecord.Comment
// fields are ignored.
//
// However, not all nodes in the tree should be collapsed as a single-line.
// If a node can be collapsed as a single-line, it is replaced by a textLine
// node. Since the top-level node cannot replace itself, this also returns
// the current node itself.
//
// This does not mutate the receiver.
formatCompactTo([]byte, diffMode) ([]byte, textNode)
// formatExpandedTo formats the contents of the tree as a multi-line string
// to the provided buffer. In order for column alignment to operate well,
// formatCompactTo must be called before calling formatExpandedTo.
formatExpandedTo([]byte, diffMode, indentMode) []byte
}
// textWrap is a wrapper that concatenates a prefix and/or a suffix
// to the underlying node.
type textWrap struct {
Prefix string // e.g., "bytes.Buffer{"
Value textNode // textWrap | textList | textLine
Suffix string // e.g., "}"
Metadata interface{} // arbitrary metadata; has no effect on formatting
}
func (s *textWrap) Len() int {
return len(s.Prefix) + s.Value.Len() + len(s.Suffix)
}
func (s1 *textWrap) Equal(s2 textNode) bool {
if s2, ok := s2.(*textWrap); ok {
return s1.Prefix == s2.Prefix && s1.Value.Equal(s2.Value) && s1.Suffix == s2.Suffix
}
return false
}
func (s *textWrap) String() string {
var d diffMode
var n indentMode
_, s2 := s.formatCompactTo(nil, d)
b := n.appendIndent(nil, d) // Leading indent
b = s2.formatExpandedTo(b, d, n) // Main body
b = append(b, '\n') // Trailing newline
return string(b)
}
func (s *textWrap) formatCompactTo(b []byte, d diffMode) ([]byte, textNode) {
n0 := len(b) // Original buffer length
b = append(b, s.Prefix...)
b, s.Value = s.Value.formatCompactTo(b, d)
b = append(b, s.Suffix...)
if _, ok := s.Value.(textLine); ok {
return b, textLine(b[n0:])
}
return b, s
}
func (s *textWrap) formatExpandedTo(b []byte, d diffMode, n indentMode) []byte {
b = append(b, s.Prefix...)
b = s.Value.formatExpandedTo(b, d, n)
b = append(b, s.Suffix...)
return b
}
// textList is a comma-separated list of textWrap or textLine nodes.
// The list may be formatted as multi-lines or single-line at the discretion
// of the textList.formatCompactTo method.
type textList []textRecord
type textRecord struct {
Diff diffMode // e.g., 0 or '-' or '+'
Key string // e.g., "MyField"
Value textNode // textWrap | textLine
ElideComma bool // avoid trailing comma
Comment fmt.Stringer // e.g., "6 identical fields"
}
// AppendEllipsis appends a new ellipsis node to the list if none already
// exists at the end. If cs is non-zero it coalesces the statistics with the
// previous diffStats.
func (s *textList) AppendEllipsis(ds diffStats) {
hasStats := !ds.IsZero()
if len(*s) == 0 || !(*s)[len(*s)-1].Value.Equal(textEllipsis) {
if hasStats {
*s = append(*s, textRecord{Value: textEllipsis, ElideComma: true, Comment: ds})
} else {
*s = append(*s, textRecord{Value: textEllipsis, ElideComma: true})
}
return
}
if hasStats {
(*s)[len(*s)-1].Comment = (*s)[len(*s)-1].Comment.(diffStats).Append(ds)
}
}
func (s textList) Len() (n int) {
for i, r := range s {
n += len(r.Key)
if r.Key != "" {
n += len(": ")
}
n += r.Value.Len()
if i < len(s)-1 {
n += len(", ")
}
}
return n
}
func (s1 textList) Equal(s2 textNode) bool {
if s2, ok := s2.(textList); ok {
if len(s1) != len(s2) {
return false
}
for i := range s1 {
r1, r2 := s1[i], s2[i]
if !(r1.Diff == r2.Diff && r1.Key == r2.Key && r1.Value.Equal(r2.Value) && r1.Comment == r2.Comment) {
return false
}
}
return true
}
return false
}
func (s textList) String() string {
return (&textWrap{Prefix: "{", Value: s, Suffix: "}"}).String()
}
func (s textList) formatCompactTo(b []byte, d diffMode) ([]byte, textNode) {
s = append(textList(nil), s...) // Avoid mutating original
// Determine whether we can collapse this list as a single line.
n0 := len(b) // Original buffer length
var multiLine bool
for i, r := range s {
if r.Diff == diffInserted || r.Diff == diffRemoved {
multiLine = true
}
b = append(b, r.Key...)
if r.Key != "" {
b = append(b, ": "...)
}
b, s[i].Value = r.Value.formatCompactTo(b, d|r.Diff)
if _, ok := s[i].Value.(textLine); !ok {
multiLine = true
}
if r.Comment != nil {
multiLine = true
}
if i < len(s)-1 {
b = append(b, ", "...)
}
}
// Force multi-lined output when printing a removed/inserted node that
// is sufficiently long.
if (d == diffInserted || d == diffRemoved) && len(b[n0:]) > maxColumnLength {
multiLine = true
}
if !multiLine {
return b, textLine(b[n0:])
}
return b, s
}
func (s textList) formatExpandedTo(b []byte, d diffMode, n indentMode) []byte {
alignKeyLens := s.alignLens(
func(r textRecord) bool {
_, isLine := r.Value.(textLine)
return r.Key == "" || !isLine
},
func(r textRecord) int { return utf8.RuneCountInString(r.Key) },
)
alignValueLens := s.alignLens(
func(r textRecord) bool {
_, isLine := r.Value.(textLine)
return !isLine || r.Value.Equal(textEllipsis) || r.Comment == nil
},
func(r textRecord) int { return utf8.RuneCount(r.Value.(textLine)) },
)
// Format lists of simple lists in a batched form.
// If the list is sequence of only textLine values,
// then batch multiple values on a single line.
var isSimple bool
for _, r := range s {
_, isLine := r.Value.(textLine)
isSimple = r.Diff == 0 && r.Key == "" && isLine && r.Comment == nil
if !isSimple {
break
}
}
if isSimple {
n++
var batch []byte
emitBatch := func() {
if len(batch) > 0 {
b = n.appendIndent(append(b, '\n'), d)
b = append(b, bytes.TrimRight(batch, " ")...)
batch = batch[:0]
}
}
for _, r := range s {
line := r.Value.(textLine)
if len(batch)+len(line)+len(", ") > maxColumnLength {
emitBatch()
}
batch = append(batch, line...)
batch = append(batch, ", "...)
}
emitBatch()
n--
return n.appendIndent(append(b, '\n'), d)
}
// Format the list as a multi-lined output.
n++
for i, r := range s {
b = n.appendIndent(append(b, '\n'), d|r.Diff)
if r.Key != "" {
b = append(b, r.Key+": "...)
}
b = alignKeyLens[i].appendChar(b, ' ')
b = r.Value.formatExpandedTo(b, d|r.Diff, n)
if !r.ElideComma {
b = append(b, ',')
}
b = alignValueLens[i].appendChar(b, ' ')
if r.Comment != nil {
b = append(b, " // "+r.Comment.String()...)
}
}
n--
return n.appendIndent(append(b, '\n'), d)
}
func (s textList) alignLens(
skipFunc func(textRecord) bool,
lenFunc func(textRecord) int,
) []repeatCount {
var startIdx, endIdx, maxLen int
lens := make([]repeatCount, len(s))
for i, r := range s {
if skipFunc(r) {
for j := startIdx; j < endIdx && j < len(s); j++ {
lens[j] = repeatCount(maxLen - lenFunc(s[j]))
}
startIdx, endIdx, maxLen = i+1, i+1, 0
} else {
if maxLen < lenFunc(r) {
maxLen = lenFunc(r)
}
endIdx = i + 1
}
}
for j := startIdx; j < endIdx && j < len(s); j++ {
lens[j] = repeatCount(maxLen - lenFunc(s[j]))
}
return lens
}
// textLine is a single-line segment of text and is always a leaf node
// in the textNode tree.
type textLine []byte
var (
textNil = textLine("nil")
textEllipsis = textLine("...")
)
func (s textLine) Len() int {
return len(s)
}
func (s1 textLine) Equal(s2 textNode) bool {
if s2, ok := s2.(textLine); ok {
return bytes.Equal([]byte(s1), []byte(s2))
}
return false
}
func (s textLine) String() string {
return string(s)
}
func (s textLine) formatCompactTo(b []byte, d diffMode) ([]byte, textNode) {
return append(b, s...), s
}
func (s textLine) formatExpandedTo(b []byte, _ diffMode, _ indentMode) []byte {
return append(b, s...)
}
type diffStats struct {
Name string
NumIgnored int
NumIdentical int
NumRemoved int
NumInserted int
NumModified int
}
func (s diffStats) IsZero() bool {
s.Name = ""
return s == diffStats{}
}
func (s diffStats) NumDiff() int {
return s.NumRemoved + s.NumInserted + s.NumModified
}
func (s diffStats) Append(ds diffStats) diffStats {
assert(s.Name == ds.Name)
s.NumIgnored += ds.NumIgnored
s.NumIdentical += ds.NumIdentical
s.NumRemoved += ds.NumRemoved
s.NumInserted += ds.NumInserted
s.NumModified += ds.NumModified
return s
}
// String prints a humanly-readable summary of coalesced records.
//
// Example:
//
// diffStats{Name: "Field", NumIgnored: 5}.String() => "5 ignored fields"
func (s diffStats) String() string {
var ss []string
var sum int
labels := [...]string{"ignored", "identical", "removed", "inserted", "modified"}
counts := [...]int{s.NumIgnored, s.NumIdentical, s.NumRemoved, s.NumInserted, s.NumModified}
for i, n := range counts {
if n > 0 {
ss = append(ss, fmt.Sprintf("%d %v", n, labels[i]))
}
sum += n
}
// Pluralize the name (adjusting for some obscure English grammar rules).
name := s.Name
if sum > 1 {
name += "s"
if strings.HasSuffix(name, "ys") {
name = name[:len(name)-2] + "ies" // e.g., "entrys" => "entries"
}
}
// Format the list according to English grammar (with Oxford comma).
switch n := len(ss); n {
case 0:
return ""
case 1, 2:
return strings.Join(ss, " and ") + " " + name
default:
return strings.Join(ss[:n-1], ", ") + ", and " + ss[n-1] + " " + name
}
}
type commentString string
func (s commentString) String() string { return string(s) }
// Copyright 2019, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package cmp
import "reflect"
// valueNode represents a single node within a report, which is a
// structured representation of the value tree, containing information
// regarding which nodes are equal or not.
type valueNode struct {
parent *valueNode
Type reflect.Type
ValueX reflect.Value
ValueY reflect.Value
// NumSame is the number of leaf nodes that are equal.
// All descendants are equal only if NumDiff is 0.
NumSame int
// NumDiff is the number of leaf nodes that are not equal.
NumDiff int
// NumIgnored is the number of leaf nodes that are ignored.
NumIgnored int
// NumCompared is the number of leaf nodes that were compared
// using an Equal method or Comparer function.
NumCompared int
// NumTransformed is the number of non-leaf nodes that were transformed.
NumTransformed int
// NumChildren is the number of transitive descendants of this node.
// This counts from zero; thus, leaf nodes have no descendants.
NumChildren int
// MaxDepth is the maximum depth of the tree. This counts from zero;
// thus, leaf nodes have a depth of zero.
MaxDepth int
// Records is a list of struct fields, slice elements, or map entries.
Records []reportRecord // If populated, implies Value is not populated
// Value is the result of a transformation, pointer indirect, of
// type assertion.
Value *valueNode // If populated, implies Records is not populated
// TransformerName is the name of the transformer.
TransformerName string // If non-empty, implies Value is populated
}
type reportRecord struct {
Key reflect.Value // Invalid for slice element
Value *valueNode
}
func (parent *valueNode) PushStep(ps PathStep) (child *valueNode) {
vx, vy := ps.Values()
child = &valueNode{parent: parent, Type: ps.Type(), ValueX: vx, ValueY: vy}
switch s := ps.(type) {
case StructField:
assert(parent.Value == nil)
parent.Records = append(parent.Records, reportRecord{Key: reflect.ValueOf(s.Name()), Value: child})
case SliceIndex:
assert(parent.Value == nil)
parent.Records = append(parent.Records, reportRecord{Value: child})
case MapIndex:
assert(parent.Value == nil)
parent.Records = append(parent.Records, reportRecord{Key: s.Key(), Value: child})
case Indirect:
assert(parent.Value == nil && parent.Records == nil)
parent.Value = child
case TypeAssertion:
assert(parent.Value == nil && parent.Records == nil)
parent.Value = child
case Transform:
assert(parent.Value == nil && parent.Records == nil)
parent.Value = child
parent.TransformerName = s.Name()
parent.NumTransformed++
default:
assert(parent == nil) // Must be the root step
}
return child
}
func (r *valueNode) Report(rs Result) {
assert(r.MaxDepth == 0) // May only be called on leaf nodes
if rs.ByIgnore() {
r.NumIgnored++
} else {
if rs.Equal() {
r.NumSame++
} else {
r.NumDiff++
}
}
assert(r.NumSame+r.NumDiff+r.NumIgnored == 1)
if rs.ByMethod() {
r.NumCompared++
}
if rs.ByFunc() {
r.NumCompared++
}
assert(r.NumCompared <= 1)
}
func (child *valueNode) PopStep() (parent *valueNode) {
if child.parent == nil {
return nil
}
parent = child.parent
parent.NumSame += child.NumSame
parent.NumDiff += child.NumDiff
parent.NumIgnored += child.NumIgnored
parent.NumCompared += child.NumCompared
parent.NumTransformed += child.NumTransformed
parent.NumChildren += child.NumChildren + 1
if parent.MaxDepth < child.MaxDepth+1 {
parent.MaxDepth = child.MaxDepth + 1
}
return parent
}