[PATCH] honor repack.usedeltabaseoffset when fetching packs

[Nicolas Pitre <nico@cam.org>]

If the local receiving repository has disabled the use of delta base
offset, for example to retain compatibility with older versions of
Git that predate OFS_DELTA, we shouldn't ask for ofs-delta support
when we obtain a pack from the remote server.

[ issue noticed by Shawn Pearce ]

Signed-off-by: Nicolas Pitre <nico@cam.org>
---

On Fri, 1 May 2009, Nicolas Pitre wrote:

> Good point.  I doubt it actually matters in practice or we would have 
> heard about some complaints by now.  But for consistency sake I should 
> produce a similar patch for C git as well.

Here it is, with commit log stolen from Shawn's JGit patch.

 builtin-fetch-pack.c |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletions(-)

diff --git a/builtin-fetch-pack.c b/builtin-fetch-pack.c
index 5d134be..012d044 100644
--- a/builtin-fetch-pack.c
+++ b/builtin-fetch-pack.c
@@ -13,6 +13,7 @@
 static int transfer_unpack_limit = -1;
 static int fetch_unpack_limit = -1;
 static int unpack_limit = 100;
+static int prefer_ofs_delta = 1;
 static struct fetch_pack_args args = {
 	/* .uploadpack = */ "git-upload-pack",
 };
@@ -200,7 +201,7 @@ static int find_common(int fd[2], unsigned char *result_sha1,
 				     (args.use_thin_pack ? " thin-pack" : ""),
 				     (args.no_progress ? " no-progress" : ""),
 				     (args.include_tag ? " include-tag" : ""),
-				     " ofs-delta");
+				     (prefer_ofs_delta ? " ofs-delta" : ""));
 		else
 			packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
 		fetching++;
@@ -596,6 +597,11 @@ static struct ref *do_fetch_pack(int fd[2],
 			fprintf(stderr, "Server supports side-band\n");
 		use_sideband = 1;
 	}
+	if (server_supports("ofs-delta")) {
+		if (args.verbose)
+			fprintf(stderr, "Server supports ofs-delta\n");
+	} else
+		prefer_ofs_delta = 0;
 	if (everything_local(&ref, nr_match, match)) {
 		packet_flush(fd[1]);
 		goto all_done;
@@ -648,6 +654,11 @@ static int fetch_pack_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	if (strcmp(var, "repack.usedeltabaseoffset") == 0) {
+		prefer_ofs_delta = git_config_bool(var, value);
+		return 0;
+	}
+
 	return git_default_config(var, value, cb);
 }