Issue #23622: Unknown escapes in regular expressions that consist of ``'\'``
and ASCII letter now raise a deprecation warning and will be forbidden in
Python 3.6.
diff --git a/Lib/sre_parse.py b/Lib/sre_parse.py
index 98afd7c..af729c3 100644
--- a/Lib/sre_parse.py
+++ b/Lib/sre_parse.py
@@ -21,6 +21,7 @@
OCTDIGITS = frozenset("01234567")
HEXDIGITS = frozenset("0123456789abcdefABCDEF")
+ASCIILETTERS = frozenset("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
WHITESPACE = frozenset(" \t\n\r\v\f")
@@ -344,6 +345,10 @@
elif c in DIGITS:
raise ValueError
if len(escape) == 2:
+ if c in ASCIILETTERS:
+ import warnings
+ warnings.warn('bad escape %s' % escape,
+ DeprecationWarning, stacklevel=8)
return LITERAL, ord(escape[1])
except ValueError:
pass
@@ -407,6 +412,10 @@
return GROUPREF, group
raise ValueError
if len(escape) == 2:
+ if c in ASCIILETTERS:
+ import warnings
+ warnings.warn('bad escape %s' % escape,
+ DeprecationWarning, stacklevel=8)
return LITERAL, ord(escape[1])
except ValueError:
pass
@@ -903,7 +912,10 @@
try:
this = chr(ESCAPES[this][1])
except KeyError:
- pass
+ if c in ASCIILETTERS:
+ import warnings
+ warnings.warn('bad escape %s' % this,
+ DeprecationWarning, stacklevel=5)
lappend(this)
else:
lappend(this)