sha1_file.c: the global packed_git variable static to the filesz/packed-git-static

This is a first step in making the codebase thread-safe.  By and
large, the operations which might benefit from threading are those
that work with pack files (e.g., checkout, blame), so the focus of
this patch is stop leaking the global list of pack files outside of
sha1_file.c.

The next step will be to control access to the list of pack files
with a mutex.  However, that alone is not enough to make pack file
access thread safe.  Even in a read-only operation, the window list
associated with each pack file will need to be controlled.
Additionally, the global counters in sha1_file.c will need to be
controlled.

This patch is a pure refactor with no functional changes, so it
shouldn't require any additional tests.  Adding the actual locks
will be a functional change, and will require additional tests.

[jc: with minimul style fixes before a full review]

Signed-off-by: Stefan Zager <szager@chromium.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/http-walker.c b/http-walker.c
index 1516c5eb29..d9d758ad95 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -405,7 +405,7 @@ static int http_fetch_pack(struct walker *walker, struct alt_base *repo, unsigne
 
 	if (fetch_indices(walker, repo))
 		return -1;
-	target = find_sha1_pack(sha1, repo->packs);
+	target = repo->packs ? find_sha1_pack(sha1, repo->packs) : NULL;
 	if (!target)
 		return -1;