[PATCH v3 1/3] read-cache.c: Handle long filenames correctly

[Thomas Gummerer <t.gummerer@gmail.com>]

Make git handle long file/path names (> 4096 characters) correctly.

There is a bug in the current version, which causes very long
file/pathnames to be handled incorrectly, or not even added to
the index, if they share the first 4096 characters.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
---
 read-cache.c              |    9 +++++--
 t/t0007-long-filenames.sh |   62 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 2 deletions(-)
 create mode 100755 t/t0007-long-filenames.sh

diff --git a/read-cache.c b/read-cache.c
index ef355cc..4c6bf5f 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -399,8 +399,13 @@ int cache_name_compare(const char *name1, int flags1, const char *name2, int fla
 {
 	int len1 = flags1 & CE_NAMEMASK;
 	int len2 = flags2 & CE_NAMEMASK;
-	int len = len1 < len2 ? len1 : len2;
-	int cmp;
+	int len, cmp;
+
+	if (len1 >= CE_NAMEMASK)
+		len1 = strlen(name1 + CE_NAMEMASK) + CE_NAMEMASK;
+	if (len2 >= CE_NAMEMASK)
+		len2 = strlen(name2 + CE_NAMEMASK) + CE_NAMEMASK;
+	len = len1 < len2 ? len1 : len2;
 
 	cmp = memcmp(name1, name2, len);
 	if (cmp)
diff --git a/t/t0007-long-filenames.sh b/t/t0007-long-filenames.sh
new file mode 100755
index 0000000..2cf6035
--- /dev/null
+++ b/t/t0007-long-filenames.sh
@@ -0,0 +1,62 @@
+
+#!/bin/sh
+
+test_description='very long file names in the index handled correctly'
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	git init &&
+
+	a=a && # 1
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 16
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 256
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 4096
+	a=${a}q &&
+
+	>path1 &&
+	git update-index --add path1 &&
+	(
+		git ls-files -s path1 |
+		sed -e "s/	.*/	/" |
+		tr -d "\012"
+		echo "$a"
+	) | git update-index --index-info &&
+
+	a=a && # 1
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 16
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 256
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 4096
+	a=${a}e &&
+
+	>path2 &&
+	git update-index --add path2 &&
+	(
+		git ls-files -s path2 |
+		sed -e "s/	.*/	/" |
+		tr -d "\012"
+		echo "$a"
+	) | git update-index --index-info &&
+	len=$(git ls-files "a*" | wc -c) &&
+	test $len = 8196
+'
+
+test_expect_success 'validate git ls-files output for a known tree' '
+	git ls-files "a*" >current &&
+	a=a && # 1
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 16
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 256
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 4096
+	a=${a}e &&
+	echo $a >expected &&
+
+	a=a && # 1
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 16
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 256
+	a=$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a$a && # 4096
+	a=${a}q &&
+	echo $a >>expected &&
+
+	test_cmp expected current
+'
+
+test_done
-- 
1.7.10.GIT