[PATCH 1/2] fetch: run gc --auto after fetching

[Jeff King <peff@peff.net>]

We generally try to run "gc --auto" after any commands that
might introduce a large number of new objects. An obvious
place to do so is after running "fetch", which may introduce
new loose objects or packs (depending on the size of the
fetch).

While an active developer repository will probably
eventually trigger a "gc --auto" on another action (e.g.,
git-rebase), there are two good reasons why it is nicer to
do it at fetch time:

  1. Read-only repositories which track an upstream (e.g., a
     continuous integration server which fetches and builds,
     but never makes new commits) will accrue loose objects
     and small packs, but never coalesce them into a more
     efficient larger pack.

  2. Fetching is often already perceived to be slow to the
     user, since they have to wait on the network. It's much
     more pleasant to include a potentially slow auto-gc as
     part of the already-long network fetch than in the
     middle of productive work with git-rebase or similar.

Signed-off-by: Jeff King <peff@peff.net>
---
The original "gc --auto" patch in 2007 suggested adding this to fetch,
but we never did (there was some brief mention that maybe tweaking
fetch.unpacklimit would be relevant, but I think you would eventually
want to gc, whether you are accruing packs or loose objects).

I didn't bother protecting this with an option (as we do for
receive.gc). I don't see much point, as anybody who doesn't want gc on
their client repos will already have set gc.auto to prevent it from
triggering via other commands).

 builtin/fetch.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 4b5a898..1ddbf0d 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -959,6 +959,9 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 	struct string_list list = STRING_LIST_INIT_NODUP;
 	struct remote *remote;
 	int result = 0;
+	static const char *argv_gc_auto[] = {
+		"gc", "--auto", NULL,
+	};
 
 	packet_trace_identity("fetch");
 
@@ -1026,5 +1029,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 	list.strdup_strings = 1;
 	string_list_clear(&list, 0);
 
+	run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
+
 	return result;
 }
-- 
1.8.1.rc0.4.g5948dfd.dirty