gh-98401: Invalid escape sequences emits SyntaxWarning (#99011)

A backslash-character pair that is not a valid escape sequence now
generates a SyntaxWarning, instead of DeprecationWarning.  For
example, re.compile("\d+\.\d+") now emits a SyntaxWarning ("\d" is an
invalid escape sequence), use raw strings for regular expression:
re.compile(r"\d+\.\d+"). In a future Python version, SyntaxError will
eventually be raised, instead of SyntaxWarning.

Octal escapes with value larger than 0o377 (ex: "\477"), deprecated
in Python 3.11, now produce a SyntaxWarning, instead of
DeprecationWarning. In a future Python version they will be
eventually a SyntaxError.

codecs.escape_decode() and codecs.unicode_escape_decode() are left
unchanged: they still emit DeprecationWarning.

* The parser only emits SyntaxWarning for Python 3.12 (feature
  version), and still emits DeprecationWarning on older Python
  versions.
* Fix SyntaxWarning by using raw strings in Tools/c-analyzer/ and
  wasm_build.py.
This commit is contained in:
Victor Stinner 2022-11-03 17:53:25 +01:00 committed by GitHub
parent 916af11a97
commit a60ddd31be
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11 changed files with 69 additions and 29 deletions

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@ -612,9 +612,13 @@ Notes:
As in Standard C, up to three octal digits are accepted.
.. versionchanged:: 3.11
Octal escapes with value larger than ``0o377`` produce a :exc:`DeprecationWarning`.
In a future Python version they will be a :exc:`SyntaxWarning` and
eventually a :exc:`SyntaxError`.
Octal escapes with value larger than ``0o377`` produce a
:exc:`DeprecationWarning`.
.. versionchanged:: 3.12
Octal escapes with value larger than ``0o377`` produce a
:exc:`SyntaxWarning`. In a future Python version they will be eventually
a :exc:`SyntaxError`.
(3)
Unlike in Standard C, exactly two hex digits are required.
@ -646,9 +650,11 @@ escape sequences only recognized in string literals fall into the category of
unrecognized escapes for bytes literals.
.. versionchanged:: 3.6
Unrecognized escape sequences produce a :exc:`DeprecationWarning`. In
a future Python version they will be a :exc:`SyntaxWarning` and
eventually a :exc:`SyntaxError`.
Unrecognized escape sequences produce a :exc:`DeprecationWarning`.
.. versionchanged:: 3.12
Unrecognized escape sequences produce a :exc:`SyntaxWarning`. In a future
Python version they will be eventually a :exc:`SyntaxError`.
Even in a raw literal, quotes can be escaped with a backslash, but the
backslash remains in the result; for example, ``r"\""`` is a valid string