From ab292bc4f30dd29d3d111b040b9e982f20b9ceb7 Mon Sep 17 00:00:00 2001 From: Michael Haggerty Date: Mon, 22 Apr 2013 21:52:25 +0200 Subject: repack_without_ref(): silence errors for dangling packed refs Stop emitting an error message when deleting a packed reference if we find another dangling packed reference that is overridden by a loose reference. See the previous commit for a longer explanation of the issue. We have to be careful to make sure that the invalid packed reference really *is* overridden by a loose reference; otherwise what we have found is repository corruption, which we *should* report. Please note that this approach is vulnerable to a race condition similar to the race conditions already known to affect packed references [1]: * Process 1 tries to peel packed reference X as part of deleting another packed reference. It discovers that X does not refer to a valid object (because the object that it referred to has been garbage collected). * Process 2 tries to delete reference X. It starts by deleting the loose reference X. * Process 1 checks whether there is a loose reference X. There is not (it has just been deleted by process 2), so process 1 reports a spurious error "X does not point to a valid object!" The worst case seems relatively harmless, and the fix is identical to the fix that will be needed for the other race conditions (namely holding a lock on the packed-refs file during *all* reference deletions), so we leave the cleaning up of all of them as a future project. [1] http://thread.gmane.org/gmane.comp.version-control.git/211956 Signed-off-by: Michael Haggerty Signed-off-by: Junio C Hamano --- t/t3210-pack-refs.sh | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 't') diff --git a/t/t3210-pack-refs.sh b/t/t3210-pack-refs.sh index 675f06a02d..1a2080e3dc 100755 --- a/t/t3210-pack-refs.sh +++ b/t/t3210-pack-refs.sh @@ -140,7 +140,7 @@ test_expect_success 'delete ref with dangling packed version' ' test_cmp /dev/null result ' -test_expect_failure 'delete ref while another dangling packed ref' ' +test_expect_success 'delete ref while another dangling packed ref' ' git branch lamb && git commit --allow-empty -m "future garbage" && git pack-refs --all && -- cgit v1.2.1