[PATCH] exclude: fix a bug in prefix comparison optimization

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.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 <pclouds@gmail.com>
---
 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