# [PATCH] exclude: fix a bug in prefix comparison optimization 5 messages from 2012-10-14 to 2012-10-15. Participants: Nguyễn Thái Ngọc Duy, Junio C Hamano, Nguyen Thai Ngoc Duy. Thread: https://gitlist.dev/t/31812 ## Nguyễn Thái Ngọc Duy, 2012-10-14 11:35 Subject: [PATCH] exclude: fix a bug in prefix comparison optimization Message-ID: <1350214522-3242-1-git-send-email-pclouds@gmail.com> URL: https://gitlist.dev/e/1350214522-3242-1-git-send-email-pclouds%40gmail.com ``` When "namelen" becomes zero at this stage, we have matched the fixed part, but whether it actually matches the pattern still depends on the pattern in "exclude". As demonstrated in t3001, path "three/a.3" exists and it matches the "three/a.3" part in pattern "three/a.3[abc]", but that does not mean a true match. Don't be too optimistic and let fnmatch() do the job. Signed-off-by: Nguyễn Thái Ngọc Duy --- dir.c | 2 +- t/t3001-ls-files-others-exclude.sh | 6 ++++++ 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/dir.c b/dir.c index 4868339..90bf3a4 100644 --- a/dir.c +++ b/dir.c @@ -575,7 +575,7 @@ int excluded_from_list(const char *pathname, namelen -= prefix; } - if (!namelen || !fnmatch_icase(exclude, name, FNM_PATHNAME)) + if (!fnmatch_icase(exclude, name, FNM_PATHNAME)) return to_exclude; } return -1; /* undecided */ diff --git a/t/t3001-ls-files-others-exclude.sh b/t/t3001-ls-files-others-exclude.sh index c8fe978..dc2f045 100755 --- a/t/t3001-ls-files-others-exclude.sh +++ b/t/t3001-ls-files-others-exclude.sh @@ -214,4 +214,10 @@ test_expect_success 'subdirectory ignore (l1)' ' test_cmp expect actual ' +test_expect_success 'pattern matches prefix completely' ' + : >expect && + git ls-files -i -o --exclude "/three/a.3[abc]" >actual && + test_cmp expect actual +' + test_done -- 1.8.0.rc2.11.g2b79d01 ``` ## Junio C Hamano, 2012-10-14 17:36 Subject: Re: [PATCH] exclude: fix a bug in prefix comparison optimization Message-ID: <7v8vb9yn09.fsf@alter.siamese.dyndns.org> URL: https://gitlist.dev/e/7v8vb9yn09.fsf%40alter.siamese.dyndns.org In-Reply-To: <1350214522-3242-1-git-send-email-pclouds@gmail.com> ``` Nguyễn Thái Ngọc Duy writes: > When "namelen" becomes zero at this stage, we have matched the fixed > part, but whether it actually matches the pattern still depends on the > pattern in "exclude". As demonstrated in t3001, path "three/a.3" > exists and it matches the "three/a.3" part in pattern "three/a.3[abc]", > but that does not mean a true match. > > Don't be too optimistic and let fnmatch() do the job. Yeah, the existing code is correct _only_ if the pattern part can match an empty string (e.g. "three/a.3*") and this is a correct fix. With your "teach attr.c match the same optimization as dir.c" series, you would need something like this diff --git i/attr.c w/attr.c index 6d39406..528e935 100644 --- i/attr.c +++ w/attr.c @@ -710,7 +710,7 @@ static int path_matches(const char *pathname, int pathlen, * if the non-wildcard part is longer than the remaining * pathname, surely it cannot match. */ - if (!namelen || prefix > namelen) + if (prefix > namelen) return 0; if (baselen != 0) baselen++; Comparing the corresponding code in dir.c, there is no "compare the literal prefix part with strcmp() before doing the fnmatch()" optimization. Intended? (warning: I haven't had my caffeine yet) ``` ## Junio C Hamano, 2012-10-14 18:25 Subject: Re: [PATCH] exclude: fix a bug in prefix comparison optimization Message-ID: <7vobk4ykpf.fsf@alter.siamese.dyndns.org> URL: https://gitlist.dev/e/7vobk4ykpf.fsf%40alter.siamese.dyndns.org In-Reply-To: <7v8vb9yn09.fsf@alter.siamese.dyndns.org> ``` Junio C Hamano writes: > Comparing the corresponding code in dir.c, there is no "compare the > literal prefix part with strcmp() before doing the fnmatch()" > optimization. Intended? > > (warning: I haven't had my caffeine yet) And it turns out that at the point I wrote the response, I still had the attr-match-optim-more updates to be read in my mailbox ;-) ``` ## Nguyen Thai Ngoc Duy, 2012-10-15 04:09 Subject: Re: [PATCH] exclude: fix a bug in prefix comparison optimization Message-ID: URL: https://gitlist.dev/e/CACsJy8DEqkPob%2BKjFS_Y3BraS40CSP7snS3aB41hg0Ng0DuJDg%40mail.gmail.com In-Reply-To: <7v8vb9yn09.fsf@alter.siamese.dyndns.org> ``` On Mon, Oct 15, 2012 at 12:36 AM, Junio C Hamano wrote: > With your "teach attr.c match the same optimization as dir.c" > series, you would need something like this > > diff --git i/attr.c w/attr.c > index 6d39406..528e935 100644 > --- i/attr.c > +++ w/attr.c > @@ -710,7 +710,7 @@ static int path_matches(const char *pathname, int pathlen, > * if the non-wildcard part is longer than the remaining > * pathname, surely it cannot match. > */ > - if (!namelen || prefix > namelen) > + if (prefix > namelen) > return 0; > if (baselen != 0) > baselen++; If there's still a chance to rewrite attr-match-optim-more series (I see it's in next now), then I could reorder the patches so that excluded_from_list code refactoring goes first, then rewrite "teach attr.c match... as dir.c" patch makes use of the new functions without code duplication. The end result would be the same, except that we won't see this bug in attr.c's history. Not much value so if it may take a lot of your time, don't bother. -- Duy ``` ## Junio C Hamano, 2012-10-15 04:28 Subject: Re: [PATCH] exclude: fix a bug in prefix comparison optimization Message-ID: <7vk3usxssf.fsf@alter.siamese.dyndns.org> URL: https://gitlist.dev/e/7vk3usxssf.fsf%40alter.siamese.dyndns.org In-Reply-To: ``` Nguyen Thai Ngoc Duy writes: > On Mon, Oct 15, 2012 at 12:36 AM, Junio C Hamano wrote: >> With your "teach attr.c match the same optimization as dir.c" >> series, you would need something like this >> >> diff --git i/attr.c w/attr.c >> index 6d39406..528e935 100644 >> --- i/attr.c >> +++ w/attr.c >> @@ -710,7 +710,7 @@ static int path_matches(const char *pathname, int pathlen, >> * if the non-wildcard part is longer than the remaining >> * pathname, surely it cannot match. >> */ >> - if (!namelen || prefix > namelen) >> + if (prefix > namelen) >> return 0; >> if (baselen != 0) >> baselen++; > > If there's still a chance to rewrite attr-match-optim-more series (I > see it's in next now), then I could reorder the patches so that > excluded_from_list code refactoring goes first, then rewrite "teach > attr.c match... as dir.c" patch makes use of the new functions without > code duplication. The end result would be the same, except that we > won't see this bug in attr.c's history. Not much value so if it may > take a lot of your time, don't bother. Actually it started to become nuisance to deal with conflicts among as/check-ignore and the attr/dir/wildmatch series, and I've been wondering if it makes sense to eject all of these out of 'next' (as they won't advance beyond 'next' until the next release anyway). So please go ahead and reroll the whole thing if you think the end result would be a history with better organization. ```