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[PATCH 13/14] fetch-pack: restore save_commit_buffer after use

From
JHJeff Hostetler <git@jeffhostetler.com>
Date
Nov 2, 2017, 20:31 UTC
Message-ID
<20171102203129.59417-14-git@jeffhostetler.com>
In-Reply-To
<20171102203129.59417-1-git@jeffhostetler.com>
From: Jonathan Tan <jonathantanmy@google.com>

In fetch-pack, the global variable save_commit_buffer is set to 0, but not restored to its original value after use.

In particular, if show_log() (in log-tree.c) is invoked after fetch_pack() in the same process, show_log() will return before printing out the commit message (because the invocation to get_cached_commit_buffer() returns NULL, because the commit buffer was not saved). I discovered this when attempting to run "git log -S" in a partial clone, triggering the case where revision walking lazily loads missing objects.

Therefore, restore save_commit_buffer to its original value after use.

An alternative to solve the problem I had is to replace get_cached_commit_buffer() with get_commit_buffer(). That invocation was introduced in commit a97934d ("use get_cached_commit_buffer where appropriate", 2014-06-13) to replace "commit->buffer" introduced in commit 3131b71 ("Add "--show-all" revision walker flag for debugging", 2008-02-13). In the latter commit, the commit author seems to be deciding between not showing an unparsed commit at all and showing an unparsed commit without the message (which is what the commit does), and did not mention parsing the unparsed commit, so I prefer to preserve the existing behavior.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
---
 fetch-pack.c | 4 ++++
 1 file changed, 4 insertions(+)
diff --git a/fetch-pack.c b/fetch-pack.c
index 895e8f9..121f03e 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -717,6 +717,7 @@ static int everything_local(struct fetch_pack_args *args,
 {
 	struct ref *ref;
 	int retval;
+	int old_save_commit_buffer = save_commit_buffer;
 	timestamp_t cutoff = 0;
 
 	save_commit_buffer = 0;
@@ -784,6 +785,9 @@ static int everything_local(struct fetch_pack_args *args,
 		print_verbose(args, _("already have %s (%s)"), oid_to_hex(remote),
 			      ref->name);
 	}
+
+	save_commit_buffer = old_save_commit_buffer;
+
 	return retval;
 }
 
-- 
2.9.3
Previous: Jeff HostetlerNext: Jeff Hostetler
Message 13 of 23 in “WIP Partial clone part 3: clone, fetch, fetch-pack, upload-pack, and tests”
  1. 00/14 WIP Partial clone part 3: clone, fetch, fetch-pack, upload-pack, and testsJeff Hostetler, Nov 2, 2017
  2. 02/14 clone, fetch-pack, index-pack, transport: partial cloneJeff Hostetler, Nov 2, 2017
  3. Jonathan TanNov 3, 2017
  4. Adam DinwoodieNov 8, 2017
  5. Jeff HostetlerNov 16, 2017
  6. 04/14 fetch: add object filtering for partial fetchJeff Hostetler, Nov 2, 2017
  7. Jonathan TanNov 3, 2017
  8. Jeff HostetlerNov 16, 2017
  9. 05/14 remote-curl: add object filtering for partial cloneJeff Hostetler, Nov 2, 2017
  10. 07/14 fetch-pack: test support excluding large blobsJeff Hostetler, Nov 2, 2017
  11. 08/14 fetch: add from_promisor and exclude-promisor-objects parametersJeff Hostetler, Nov 2, 2017
  12. 10/14 t5601: test for partial cloneJeff Hostetler, Nov 2, 2017
  13. 13/14 fetch-pack: restore save_commit_buffer after useJeff Hostetler, Nov 2, 2017
  14. 11/14 t5500: more tests for partial clone and fetchJeff Hostetler, Nov 2, 2017
  15. 14/14 index-pack: silently assume missing objects are promisorJeff Hostetler, Nov 2, 2017
  16. 12/14 unpack-trees: batch fetching of missing blobsJeff Hostetler, Nov 2, 2017
  17. 09/14 t5500: add fetch-pack tests for partial cloneJeff Hostetler, Nov 2, 2017
  18. 06/14 pack-objects: test support for blob filteringJeff Hostetler, Nov 2, 2017
  19. 03/14 fetch: refactor calculation of remote listJeff Hostetler, Nov 2, 2017
  20. 01/14 upload-pack: add object filtering for partial cloneJeff Hostetler, Nov 2, 2017
  21. Jonathan TanNov 2, 2017
  22. Jeff HostetlerNov 3, 2017
  23. Junio C HamanoNov 3, 2017

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