[spicysharkco]

fnmatch.fnmatch('xb', '!(a)@(b|*(c))', flags=fnmatch.EXTMATCH) raises re.error: missing ), unterminated subpattern at position 5. glob.globmatch('xb', '!(a)@(b|*(c))', flags=glob.EXTGLOB) raises the same error. The pattern is valid and xb is x followed by b, so both should return True, as Bash does. The latest release, 11.1, has the same error. It is the nested form of #218, which was fixed in #219 for !(2)_@(foo|bar).

An inverse group stays open in the regular expression until the text after it is known. When a nested extended group finishes, clean_up_inverse sets self.inv_ext = 0 while the outer inverse group is still open. The final cleanup at the end of the pattern then returns early and never closes it.

This removes that reset and has clean_up_inverse lower self.inv_ext by one for each inverse group it closes.

I added three rows to TestFnMatch.cases and two to TestGlobMatch.cases. Without the fix, pytest tests/test_fnmatch.py gives 3 failed, 200 passed, 1 skipped and pytest tests/test_globmatch.py gives 2 failed, 655 passed, 63 skipped. With it, they give 203 passed, 1 skipped and 657 passed, 63 skipped. The full suite passes with the fix. There is also a changelog line under Unreleased.

[facelessuser]

@spicysharkco, I believe the more appropriate approach is to decrement self.inv_ext inside the loop.

        index = len(current) - 1
        while index >= 0:
            if isinstance(current[index], InvPlaceholder):
                content = current[index + 1:]
                if not nested:
                    content.append(_EOP if not self.pathname else self.path_eop)
                current[index] = (
                    (''.join(content).replace('(?#)', '?:') if self.capture else ''.join(content)) +
                    (_EXCLA_GROUP_CLOSE.format(str(current[index])))
                )
                self.inv_ext -= 1
            index -= 1

[spicysharkco]

@facelessuser, done in 88b57cf: clean_up_inverse now decrements self.inv_ext for each inverse group it closes, and the reset stays removed. Translated regexes are identical to the previous commit across 15,078 generated pattern and flag combinations.

[facelessuser]

@gir-bot lgtm