threads / patch / 7790

patchdir.c(common_prefix): Fix two bugs

Subject: [PATCH] dir.c(common_prefix): Fix two bugs

## tl;dr

4 messages between Apr 23, 2007 and Apr 23, 2007. Diffs are folded; open one to read it.

replies: 3people: 2as markdown or json

Johannes Schindelin· Apr 23, 2007, 08:21 UTC · lore

The function common_prefix() is used to find the common subdirectory of a couple of pathnames. When checking if the next pathname matches up with the prefix, it incorrectly checked the whole path, not just the prefix (including the slash). Thus, the expensive part of the loop was executed always.

The other bug is more serious: if the first and the last pathname in the list have a longer common prefix than the common prefix for _all_ pathnames in the list, the longer one would be chosen. This bug was probably hidden by the fact that bash's wildcard expansion sorts the results, and the code just so happens to work with sorted input.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
	If you're up for a very surprising error message, run the test 
	without compiling git-add first...
 dir.c          |    3 ++-
 t/t3700-add.sh |    6 ++++++
 2 files changed, 8 insertions(+), 1 deletions(-)
Show changes to 2 files +8 −1

dir.c, t/t3700-add.sh

diff --git a/dir.c b/dir.c
index 6564a92..d306352 100644
--- a/dir.c
+++ b/dir.c
@@ -34,8 +34,9 @@ int common_prefix(const char **pathspec)
 	prefix = slash - path + 1;
 	while ((next = *++pathspec) != NULL) {
 		int len = strlen(next);
-		if (len >= prefix && !memcmp(path, next, len))
+		if (len >= prefix && !memcmp(path, next, prefix))
 			continue;
+		len = prefix - 1;
 		for (;;) {
 			if (!len)
 				return 0;
diff --git a/t/t3700-add.sh b/t/t3700-add.sh
index 08e0352..ad8cc7d 100755
--- a/t/t3700-add.sh
+++ b/t/t3700-add.sh
@@ -104,4 +104,10 @@ test_expect_success 'add ignored ones with -f' '
 	git-ls-files --error-unmatch d.ig/d.if d.ig/d.ig
 '
 
+mkdir 1 1/2 1/3
+touch 1/2/a 1/3/b 1/2/c
+test_expect_success 'check correct prefix detection' '
+	git add 1/2/a 1/3/b 1/2/c
+'
+
 test_done

-- 
1.5.1.1.2671.g2bc0-dirty
Junio C Hamano· Apr 23, 2007, 08:47 UTC · re: Johannes Schindelin · lore

Re: [PATCH] dir.c(common_prefix): Fix two bugs

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
> 	If you're up for a very surprising error message, run the test 
> 	without compiling git-add first...
$ PATH=/usr/bin:/bin sh t3700-add.sh -i -v
* expecting success: touch foo && git-add foo
./test-lib.sh: line 136: git-add: command not found
* FAIL 1: Test of git-add
        touch foo && git-add foo
$ echo $?
1
Johannes Schindelin· Apr 23, 2007, 09:12 UTC · re: Junio C Hamano · lore

Re: [PATCH] dir.c(common_prefix): Fix two bugs

Hi,
On Mon, 23 Apr 2007, Junio C Hamano wrote:
Show 12 quoted lines
> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
> 
> > 	If you're up for a very surprising error message, run the test 
> > 	without compiling git-add first...
> 
> $ PATH=/usr/bin:/bin sh t3700-add.sh -i -v
> * expecting success: touch foo && git-add foo
> ./test-lib.sh: line 136: git-add: command not found
> * FAIL 1: Test of git-add
>         touch foo && git-add foo
> $ echo $?
> 1
;-)

I did not say you should "make clean" first... For the record: this is what the surprising error looks like on my machine:

	* expecting success:
        	git add 1/2/a 1/3/b 1/2/c
	
	The following paths are ignored by one of your .gitignore files:
	1/3/b
	Use -f if you really want to add them.
	* FAIL 15: check correct prefix detection
The surprising factor is, of course, that there is no .gitignore file.

Ciao, Dscho

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