bpo-32912: Revert SyntaxWarning on invalid escape sequences. (GH-15195)
DeprecationWarning will continue to be emitted for invalid escape
sequences in string and bytes literals just as it did in 3.7.
SyntaxWarning may be emitted in the future. But per mailing list
discussion, we don't yet know when because we haven't settled on how to
do so in a non-disruptive manner.
(Applies 4c5b6bac2408f879231c7cd38d67657dd4804e7c to the master branch).
(This is https://github.com/python/cpython/pull/15142 for master/3.9)
https://bugs.python.org/issue32912
Automerge-Triggered-By: @gpshead
diff --git a/Doc/reference/lexical_analysis.rst b/Doc/reference/lexical_analysis.rst
index cc1b2f5..7e1e17e 100644
--- a/Doc/reference/lexical_analysis.rst
+++ b/Doc/reference/lexical_analysis.rst
@@ -594,11 +594,9 @@
unrecognized escapes for bytes literals.
.. versionchanged:: 3.6
- Unrecognized escape sequences produce a :exc:`DeprecationWarning`.
-
- .. versionchanged:: 3.8
- Unrecognized escape sequences produce a :exc:`SyntaxWarning`. In
- some future version of Python they will be a :exc:`SyntaxError`.
+ Unrecognized escape sequences produce a :exc:`DeprecationWarning`. In
+ a future Python version they will be a :exc:`SyntaxWarning` and
+ 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
diff --git a/Doc/whatsnew/3.8.rst b/Doc/whatsnew/3.8.rst
index d8062e7..82da10c 100644
--- a/Doc/whatsnew/3.8.rst
+++ b/Doc/whatsnew/3.8.rst
@@ -414,11 +414,6 @@
and :keyword:`return` statements.
(Contributed by David Cuthbert and Jordan Chapman in :issue:`32117`.)
-* A backslash-character pair that is not a valid escape sequence generates
- a :exc:`DeprecationWarning` since Python 3.6. In Python 3.8 it generates
- a :exc:`SyntaxWarning` instead.
- (Contributed by Serhiy Storchaka in :issue:`32912`.)
-
* The compiler now produces a :exc:`SyntaxWarning` in some cases when a comma
is missed before tuple or list. For example::