From: Harald van Dijk <email@example.com> To: Eric Blake <firstname.lastname@example.org>, Stephane Chazelas <email@example.com> Cc: Herbert Xu <firstname.lastname@example.org>, email@example.com, firstname.lastname@example.org Subject: Re: [v2 PATCH] expand: Always quote caret when using fnmatch Date: Mon, 21 Feb 2022 17:06:13 +0000 [thread overview] Message-ID: <email@example.com> (raw) In-Reply-To: <firstname.lastname@example.org> On 21/02/2022 16:39, Eric Blake wrote: > On Sun, Feb 20, 2022 at 07:15:44AM +0000, Stephane Chazelas wrote: >> 2022-01-19 16:37:54 +1100, Herbert Xu: >> [...] >>> This patch forces ^ to be a literal when we use fnmatch. >> [...] >> The "fix" also seems incomplete and causes at least this >> regression: >> >> $ ltrace -e fnmatch ./bin/dash -c 'case "\\" in ($1) echo match; esac' sh '[\^]' >> dash->fnmatch("[\\\\^]", "\\", 0) = 0 >> match >> >> See how that added \ caused it to be included in the set. Compare with: >> >> +++ exited (status 0) +++ >> $ ltrace -e fnmatch ./bin/dash -c 'case "\\" in ($1) echo match; esac' sh '[\!]' >> dash->fnmatch("[\\!]", "\\", 0) = 1 >> +++ exited (status 0) +++ >> $ ltrace -e fnmatch ./bin/dash -c 'case "\\" in ($1) echo match; esac' sh '[\x]' >> dash->fnmatch("[\\x]", "\\", 0) = 1 >> +++ exited (status 0) +++ > > If you want to escape ^ to always be treated as a literal when calling > fnmatch(), you have to spell it something like [[=^=]...], not [\^...] > (that is, since \^ inside  does NOT treat the \ as an escape > character, but as yet another literal character as part of the brakcet > group, you instead have to resort to calling out the literal character > ^ via alternative spellings such as by a collation equivalent). This is correct for regular expressions, unspecified for shell patterns in general after bug 1234 was resolved, and always incorrect for fnmatch() after bug 1190 was resolved. In fnmatch(), backslash has to work even inside bracket expressions. Whether it had to may not previously have been clear in the standard, but it has been made clear now and that is also how it works in glibc. That part of the patch is not a problem. Cheers, Harald van Dijk
next prev parent reply other threads:[~2022-02-21 17:06 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-01-12 16:25 possible wrong behaviour with patterns using a quoted ^ at the start of a bracket expression Christoph Anton Mitterer 2022-01-12 17:20 ` Harald van Dijk 2022-01-12 17:47 ` Christoph Anton Mitterer 2022-01-12 18:17 ` Harald van Dijk 2022-01-12 18:21 ` Christoph Anton Mitterer 2022-01-18 6:13 ` [PATCH] expand: Always quote caret when using fnmatch Herbert Xu 2022-01-18 8:44 ` Harald van Dijk 2022-01-19 5:37 ` [v2 PATCH] " Herbert Xu 2022-02-20 7:15 ` Stephane Chazelas 2022-02-21 16:39 ` Eric Blake 2022-02-21 17:06 ` Harald van Dijk [this message] 2022-02-21 19:15 ` Stephane Chazelas 2022-01-18 14:29 ` [PATCH] " Christoph Anton Mitterer 2022-01-18 14:54 ` Chet Ramey 2022-01-18 22:33 ` Herbert Xu
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