Am 11.01.23 um 19:56 schrieb Jeff King: > On Sun, Jan 08, 2023 at 01:42:04AM +0100, René Scharfe wrote: > >> REG_ENHANCED on macOS affects REG_EXTENDED as well. It unlocks e.g. >> non-greedy repetitions and inline comments. Sounds nice, but also >> potentially surprising. I was unable to find a current version of >> the re_format(7) manpage online, unfortunately. > > I'm not quite sure what you mean here by "non-greedy repetitions". > Something like: > > # prefer "foo bar" to "foo bar bar"; only matters for colorizing or > # --only-matching > git grep -E 'foo.*?bar' > > ? If so, then yeah, that changes the meaning of a bare "?" and people > might be surprised by it. Right. To be fair, question mark is a special character and you'd probably need to quote it anyway if you want to match a literal question mark. Otherwise I get: $ git grep -E 'foo.*?bar' fatal: command line, 'foo.*?bar': repetition-operator operand invalid >> Apple's latest version of Git sets NO_REGEX and thus uses >> compat/regex, if I read their source correctly: >> >> https://github.com/apple-oss-distributions/Git/blob/Git-128/src/git/Makefile#L1302 >> >> The easiest and most consistent option would be to do the same. But >> we can't do that, because it would break multibyte support, which was >> fixed by 1819ad327b (grep: fix multibyte regex handling under macOS, >> 2022-08-26), which started to use the system regex functions again. > > Looks like that NO_REGEX line was dropped by 1819ad327b. So I don't > think Apple added it themselves; their version is just based on an older > version of Git (looks like 2.24.3). Makes sense. >> Which begs the question: Isn't that a problem for the platforms that >> still have to use NO_REGEX? Shouldn't we fix compat/regex? > > I'm not sure. I always assumed our fallback was similar-ish to what was > in glibc and was thus pretty featureful, but that may not be true (it > actually comes from gawk). It looks like we just didn't pull over the > multi-byte parts in a997bf423d (compat/regex: get the gawk regex engine > to compile within git, 2010-08-17). GAWK removed NO_MBSUPPORT, NO_MBSUPPORT and mbsupport.h in the meantime. I guess that means they support multi-byte characters everywhere now. René
