[issue32998] regular expression regression in python 3.7

Change by Doug Hellmann : -- nosy: +doughellmann ___ Python tracker ___ ___

[issue32998] regular expression regression in python 3.7

mike bayer added the comment: for those watching this would be the findall() case which is consistent between pythons: import re for reg in [ 'VARCHAR(30) COLLATE "en_US"', 'VARCHAR(30)' ]: print(re.findall(r'(?: COLLATE.*)?$', reg)) output (all

[issue32998] regular expression regression in python 3.7

mike bayer added the comment: for now the quickest solution is to add "count=1" so that it only replaces once. -- ___ Python tracker

[issue32998] regular expression regression in python 3.7

Serhiy Storchaka added the comment: In your case you can just pass 1 as the fourth parameter of re.sub(). -- ___ Python tracker

[issue32998] regular expression regression in python 3.7

mike bayer added the comment: also, removing the "?" is not an option for me. I need the brackets to be placed prior to the "COLLATE" subsection, but unconditionally even if the "COLLATE" section is not present. Looking at the change the behavior seems wrong

[issue32998] regular expression regression in python 3.7

Serhiy Storchaka added the comment: Just see the re.sub() documentation for 3.7. There is also a note in the What's New document, in the "Changes in the Python API" section. -- ___ Python tracker

[issue32998] regular expression regression in python 3.7

mike bayer added the comment: can you point me to the documentation? -- ___ Python tracker ___

[issue32998] regular expression regression in python 3.7

Serhiy Storchaka added the comment: This is intentional change. Prior to 3.7 re.sub() didn't replace empty matches adjacent to a previous non-empty match. In 3.7 it does. Together with other changes this made all four functions that search multiple matches of the

[issue32998] regular expression regression in python 3.7

mike bayer added the comment: correction, that's fedora 26, not 27 -- ___ Python tracker ___

[issue32998] regular expression regression in python 3.7

New submission from mike bayer : demo: import re inner = 'VARCHAR(30) COLLATE "en_US"' result = re.sub( r'((?: COLLATE.*)?)$', r'FOO\1', inner ) print(inner) print(result) in all Python versions prior to 3.7: VARCHAR(30) COLLATE "en_US"