Re: [PATCH v2] sha1_file: do not add own object directory as alternate

[Ephrim Khong <dr.khong@gmail.com>]

When adding alternate object directories, we try not to add the
directory of the current repository to avoid cycles.  Unfortunately,
that test was broken, since it compared an absolute with a relative
path.

Signed-off-by: Ephrim Khong <dr.khong@gmail.com>
---
As proposed by Duy, v2 of the patch normalizes the object directory,
uses strcmp_icase for case-insensitive file systems, and moves the
path normalization to link_alt_odb_entries to save some cycles.

Additionally, the test is now more compact by using the already
prepared git repository instead of a new one, and tests if the
path normalization for both objectdir and alternate works.

 sha1_file.c                        | 13 +++++++++----
 t/t7702-repack-cyclic-alternate.sh | 24 ++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 4 deletions(-)
 create mode 100755 t/t7702-repack-cyclic-alternate.sh

diff --git a/sha1_file.c b/sha1_file.c
index 34d527f..88fd168 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -268,9 +268,9 @@ static struct alternate_object_database **alt_odb_tail;
  * SHA1, an extra slash for the first level indirection, and the
  * terminating NUL.
  */
-static int link_alt_odb_entry(const char *entry, const char *relative_base, int depth)
+static int link_alt_odb_entry(const char *entry, const char *relative_base,
+	int depth, const char *normalized_objdir)
 {
-	const char *objdir = get_object_directory();
 	struct alternate_object_database *ent;
 	struct alternate_object_database *alt;
 	int pfxlen, entlen;
@@ -320,7 +320,7 @@ static int link_alt_odb_entry(const char *entry, const char *relative_base, int
 			return -1;
 		}
 	}
-	if (!strcmp(ent->base, objdir)) {
+	if (!strcmp_icase(ent->base, normalized_objdir)) {
 		free(ent);
 		return -1;
 	}
@@ -344,6 +344,7 @@ static void link_alt_odb_entries(const char *alt, int len, int sep,
 	struct string_list entries = STRING_LIST_INIT_NODUP;
 	char *alt_copy;
 	int i;
+	struct strbuf objdirbuf = STRBUF_INIT;

 	if (depth > 5) {
 		error("%s: ignoring alternate object stores, nesting too deep.",
@@ -351,6 +352,9 @@ static void link_alt_odb_entries(const char *alt, int len, int sep,
 		return;
 	}

+	strbuf_addstr(&objdirbuf, absolute_path(get_object_directory()));
+	normalize_path_copy(objdirbuf.buf, objdirbuf.buf);
+
 	alt_copy = xmemdupz(alt, len);
 	string_list_split_in_place(&entries, alt_copy, sep, -1);
 	for (i = 0; i < entries.nr; i++) {
@@ -361,11 +365,12 @@ static void link_alt_odb_entries(const char *alt, int len, int sep,
 			error("%s: ignoring relative alternate object store %s",
 					relative_base, entry);
 		} else {
-			link_alt_odb_entry(entry, relative_base, depth);
+			link_alt_odb_entry(entry, relative_base, depth, objdirbuf.buf);
 		}
 	}
 	string_list_clear(&entries, 0);
 	free(alt_copy);
+	strbuf_release(&objdirbuf);
 }

 void read_info_alternates(const char * relative_base, int depth)
diff --git a/t/t7702-repack-cyclic-alternate.sh b/t/t7702-repack-cyclic-alternate.sh
new file mode 100755
index 0000000..3771613
--- /dev/null
+++ b/t/t7702-repack-cyclic-alternate.sh
@@ -0,0 +1,24 @@
+#!/bin/sh
+#
+# Copyright (c) 2014 Ephrim Khong
+#
+
+test_description='repack involving cyclic alternate'
+. ./test-lib.sh
+
+test_expect_success setup '
+	GIT_OBJECT_DIRECTORY=.git//../.git/objects &&
+	export GIT_OBJECT_DIRECTORY &&
+	touch a &&
+	git add a &&
+	git commit -m 1 &&
+	git repack -adl &&
+	echo $PWD/.git/objects/../objects > .git/objects/info/alternates
+'
+
+test_expect_success 're-packing repository with itsself as alternate' '
+	git repack -adl &&
+	git fsck
+'
+
+test_done
-- 
1.8.4.3