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1# This file is part of Hypothesis, which may be found at
2# https://github.com/HypothesisWorks/hypothesis/
3#
4# Copyright the Hypothesis Authors.
5# Individual contributors are listed in AUTHORS.rst and the git log.
6#
7# This Source Code Form is subject to the terms of the Mozilla Public License,
8# v. 2.0. If a copy of the MPL was not distributed with this file, You can
9# obtain one at https://mozilla.org/MPL/2.0/.
11import contextlib
12import os
13import sys
14import textwrap
15import traceback
16from collections.abc import Callable
17from dataclasses import dataclass
18from functools import partial
19from inspect import getfile, getsourcefile
20from pathlib import Path
21from types import ModuleType, TracebackType
23import hypothesis
24from hypothesis.errors import _Trimmable
25from hypothesis.utils.dynamicvariables import DynamicVariable
27FILE_CACHE: dict[ModuleType, dict[str, bool]] = {}
30def belongs_to(package: ModuleType) -> Callable[[str], bool]:
31 if getattr(package, "__file__", None) is None: # pragma: no cover
32 return lambda filepath: False
34 assert package.__file__ is not None
35 FILE_CACHE.setdefault(package, {})
36 cache = FILE_CACHE[package]
37 root = Path(package.__file__).resolve().parent
39 def accept(filepath: str) -> bool:
40 try:
41 return cache[filepath]
42 except KeyError:
43 pass
44 try:
45 Path(filepath).resolve().relative_to(root)
46 result = True
47 except Exception:
48 result = False
49 cache[filepath] = result
50 return result
52 accept.__name__ = f"is_{package.__name__}_file"
53 return accept
56is_hypothesis_file = belongs_to(hypothesis)
59def _last_frame_location(tb: TracebackType) -> tuple[str, int | None]:
60 # Equivalent to ``traceback.extract_tb(tb)[-1][:2]``, but much cheaper because
61 # we don't compute positions or look up source lines for every frame.
62 while tb.tb_next is not None:
63 tb = tb.tb_next
64 return tb.tb_frame.f_code.co_filename, tb.tb_lineno
67def get_trimmed_traceback(
68 exception: BaseException | None = None,
69) -> TracebackType | None:
70 """Return the current traceback, minus any frames added by Hypothesis."""
71 if exception is None:
72 _, exception, tb = sys.exc_info()
73 else:
74 tb = exception.__traceback__
75 # Avoid trimming the traceback if we're in verbose mode, or the error
76 # was raised inside Hypothesis. Additionally, the environment variable
77 # HYPOTHESIS_NO_TRACEBACK_TRIM is respected if nonempty, because verbose
78 # mode is prohibitively slow when debugging strategy recursion errors.
79 assert hypothesis.settings.default is not None
80 if (
81 tb is None
82 or os.environ.get("HYPOTHESIS_NO_TRACEBACK_TRIM")
83 or hypothesis.settings.default.verbosity >= hypothesis.Verbosity.debug
84 or (
85 is_hypothesis_file(_last_frame_location(tb)[0])
86 and not isinstance(exception, _Trimmable)
87 )
88 ):
89 return tb
90 while tb.tb_next is not None and (
91 # If the frame is from one of our files, it's been added by Hypothesis.
92 is_hypothesis_file(getsourcefile(tb.tb_frame) or getfile(tb.tb_frame))
93 # But our `@proxies` decorator overrides the source location,
94 # so we check for an attribute it injects into the frame too.
95 or tb.tb_frame.f_globals.get("__hypothesistracebackhide__") is True
96 ):
97 tb = tb.tb_next
98 return tb
101@dataclass(slots=True, frozen=True)
102class InterestingOrigin:
103 # The `interesting_origin` is how Hypothesis distinguishes between multiple
104 # failures, for reporting and also to replay from the example database (even
105 # if report_multiple_bugs=False). We traditionally use the exception type and
106 # location, but have extracted this logic in order to see through `except ...:`
107 # blocks and understand the __cause__ (`raise x from y`) or __context__ that
108 # first raised an exception as well as PEP-654 exception groups.
109 exc_type: type[BaseException]
110 filename: str | None
111 lineno: int | None
112 context: "InterestingOrigin | tuple[()]"
113 group_elems: "tuple[InterestingOrigin, ...]"
115 def __str__(self) -> str:
116 ctx = ""
117 if self.context:
118 ctx = textwrap.indent(f"\ncontext: {self.context}", prefix=" ")
119 group = ""
120 if self.group_elems:
121 chunks = "\n ".join(str(x) for x in self.group_elems)
122 group = textwrap.indent(f"\nchild exceptions:\n {chunks}", prefix=" ")
123 return f"{self.exc_type.__name__} at {self.filename}:{self.lineno}{ctx}{group}"
125 @classmethod
126 def from_exception(
127 cls, exception: BaseException, /, seen: tuple[BaseException, ...] = ()
128 ) -> "InterestingOrigin":
129 filename, lineno = None, None
130 if tb := get_trimmed_traceback(exception):
131 filename, lineno = _last_frame_location(tb)
132 seen = (*seen, exception)
133 make = partial(cls.from_exception, seen=seen)
134 context: InterestingOrigin | tuple[()] = ()
135 if exception.__context__ is not None and exception.__context__ not in seen:
136 context = make(exception.__context__)
137 return cls(
138 type(exception),
139 filename,
140 lineno,
141 # Note that if __cause__ is set it is always equal to __context__, explicitly
142 # to support introspection when debugging, so we can use that unconditionally.
143 context,
144 # We distinguish exception groups by the inner exceptions, as for __context__
145 (
146 tuple(make(exc) for exc in exception.exceptions if exc not in seen)
147 if isinstance(exception, BaseExceptionGroup)
148 else ()
149 ),
150 )
153current_pytest_item = DynamicVariable(None)
156def _get_exceptioninfo():
157 # ExceptionInfo was moved to the top-level namespace in Pytest 7.0
158 if "pytest" in sys.modules:
159 with contextlib.suppress(Exception):
160 # From Pytest 7, __init__ warns on direct calls.
161 return sys.modules["pytest"].ExceptionInfo.from_exc_info
162 if "_pytest._code" in sys.modules: # old versions only
163 with contextlib.suppress(Exception):
164 return sys.modules["_pytest._code"].ExceptionInfo
165 return None
168def format_exception(err, tb):
169 # Try using Pytest to match the currently configured traceback style
170 ExceptionInfo = _get_exceptioninfo()
171 if current_pytest_item.value is not None and ExceptionInfo is not None:
172 item = current_pytest_item.value
173 return str(item.repr_failure(ExceptionInfo((type(err), err, tb)))) + "\n"
175 # Or use better_exceptions, if that's installed and enabled
176 if "better_exceptions" in sys.modules:
177 better_exceptions = sys.modules["better_exceptions"]
178 if sys.excepthook is better_exceptions.excepthook:
179 return "".join(better_exceptions.format_exception(type(err), err, tb))
181 # If all else fails, use the standard-library formatting tools
182 return "".join(traceback.format_exception(type(err), err, tb))