Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/libcst/codemod/commands/unnecessary_format_string.py: 84%

1# Copyright (c) Meta Platforms, Inc. and affiliates. 

2# 

3# This source code is licensed under the MIT license found in the 

4# LICENSE file in the root directory of this source tree. 

5# 

6import libcst 

7import libcst.matchers as m 

8from libcst.codemod import VisitorBasedCodemodCommand 

9 

10 

11class UnnecessaryFormatString(VisitorBasedCodemodCommand): 

12 DESCRIPTION: str = ( 

13 "Converts f-strings which perform no formatting to regular strings." 

14 ) 

15 

16 @m.leave(m.FormattedString(parts=(m.FormattedStringText(),))) 

17 def _check_formatted_string( 

18 self, 

19 _original_node: libcst.FormattedString, 

20 updated_node: libcst.FormattedString, 

21 ) -> libcst.BaseExpression: 

22 old_string_inner = libcst.ensure_type( 

23 updated_node.parts[0], libcst.FormattedStringText 

24 ).value 

25 if "{{" in old_string_inner or "}}" in old_string_inner: 

26 # there are only two characters we need to worry about escaping. 

27 return updated_node 

28 

29 old_string_literal = updated_node.start + old_string_inner + updated_node.end 

30 new_string_literal = ( 

31 updated_node.start.replace("f", "").replace("F", "") 

32 + old_string_inner 

33 + updated_node.end 

34 ) 

35 

36 old_string_evaled = eval(old_string_literal) # noqa 

37 new_string_evaled = eval(new_string_literal) # noqa 

38 if old_string_evaled != new_string_evaled: 

39 warn_message = ( 

40 f"Attempted to codemod |{old_string_literal}| to " 

41 + f"|{new_string_literal}| but don't eval to the same! First is |{old_string_evaled}| and " 

42 + f"second is |{new_string_evaled}|" 

43 ) 

44 self.warn(warn_message) 

45 return updated_node 

46 

47 return libcst.SimpleString(new_string_literal)