cache_name_compare(): do not truncate while comparing paths

We failed to use ce_namelen() equivalent and instead only compared
up to the CE_NAMEMASK bytes by mistake.  Adding an overlong path
that shares the same common prefix as an existing entry in the index
did not add a new entry, but instead replaced the existing one, as
the result.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/t/t3006-ls-files-long.sh b/t/t3006-ls-files-long.sh
new file mode 100755
index 0000000..202ad65
--- /dev/null
+++ b/t/t3006-ls-files-long.sh
@@ -0,0 +1,39 @@
+#!/bin/sh
+
+test_description='overly long paths'
+. ./test-lib.sh
+
+test_expect_success setup '
+	p=filefilefilefilefilefilefilefile &&
+	p=$p$p$p$p$p$p$p$p$p$p$p$p$p$p$p$p &&
+	p=$p$p$p$p$p$p$p$p$p$p$p$p$p$p$p$p &&
+
+	path_a=${p}_a &&
+	path_z=${p}_z &&
+
+	blob_a=$(echo frotz | git hash-object -w --stdin) &&
+	blob_z=$(echo nitfol | git hash-object -w --stdin) &&
+
+	pat="100644 %s 0\t%s\n"
+'
+
+test_expect_success 'overly-long path by itself is not a problem' '
+	printf "$pat" "$blob_a" "$path_a" |
+	git update-index --add --index-info &&
+	echo "$path_a" >expect &&
+	git ls-files >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'overly-long path does not replace another by mistake' '
+	printf "$pat" "$blob_a" "$path_a" "$blob_z" "$path_z" |
+	git update-index --add --index-info &&
+	(
+		echo "$path_a"
+		echo "$path_z"
+	) >expect &&
+	git ls-files >actual &&
+	test_cmp expect actual
+'
+
+test_done