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From: Ben Peart <peartben@gmail.com>
To: Git Mailing List <git@vger.kernel.org>,
	Elijah Newren <newren@gmail.com>,
	Kevin Willford <kewillf@microsoft.com>,
	Ben Peart <benpeart@microsoft.com>
Subject: [BUG] merge-recursive overly aggressive when skipping updating the working tree
Date: Fri, 20 Jul 2018 15:53:07 -0400	[thread overview]
Message-ID: <5a8d1098-b4c5-64e1-da98-dac13521e7ba@gmail.com> (raw)

As we were attempting to migrate to 2.18 some of our internal functional 
tests failed.  The tests that failed were testing merge and cherry-pick 
when there was a merge conflict. Our tests run with sparse-checkout 
enabled which is what exposed the bug.

What is happening is that in merge_recursive, the skip-worktree bit is 
cleared on the cache entry but then the working directory isn't updated. 
  The end result is that git reports that the merged file has actually 
been deleted.

We've identified the patch that introduced the regression as:

commit 1de70dbd1ada0069d1b6cd6345323906cc9a9ed3
Author: Elijah Newren <newren@gmail.com>
Date:   Thu Apr 19 10:58:23 2018 -0700

     merge-recursive: fix check for skipability of working tree updates

     The can-working-tree-updates-be-skipped check has had a long and 
blemished
     history.  The update can be skipped iff:
       a) The merge is clean
       b) The merge matches what was in HEAD (content, mode, pathname)
       c) The target path is usable (i.e. not involved in D/F conflict)


I've written a test that can be used to reproduce the issue:


diff --git a/t/t3507-cherry-pick-conflict.sh 
b/t/t3507-cherry-pick-conflict.sh
index 7c5ad08626..de0bdc8634 100755
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -392,4 +392,17 @@ test_expect_success 'commit --amend -s places the 
sign-off at the right place' '

         test_cmp expect actual
  '

+test_expect_success 'failed cherry-pick with sparse-checkout' '
+       pristine_detach initial &&
+       git config core.sparseCheckout true &&
+       echo /unrelated >.git/info/sparse-checkout &&
+       git read-tree --reset -u HEAD &&
+       test_must_fail git cherry-pick -Xours picked>actual &&
+       test_i18ngrep ! "Changes not staged for commit:" actual &&
+       echo "/*" >.git/info/sparse-checkout &&
+       git read-tree --reset -u HEAD &&
+       git config core.sparseCheckout false &&
+       rm .git/info/sparse-checkout
+'
+
  test_done

Thanks,

Ben

             reply	other threads:[~2018-07-20 19:53 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-20 19:53 Ben Peart [this message]
2018-07-20 20:48 ` [BUG] merge-recursive overly aggressive when skipping updating the working tree Elijah Newren
2018-07-20 21:13   ` Junio C Hamano
2018-07-20 21:42     ` Elijah Newren
2018-07-20 22:05       ` Junio C Hamano
2018-07-20 23:02         ` Elijah Newren
2018-07-23 12:49           ` Ben Peart
2018-07-21  6:34 ` [PATCH 0/2] Preserve skip_worktree bit in merges when necessary Elijah Newren
2018-07-21  6:34   ` [PATCH 1/2] t3507: add a testcase showing failure with sparse checkout Elijah Newren
2018-07-21  7:21     ` Eric Sunshine
2018-07-23 13:12       ` Ben Peart
2018-07-23 18:09         ` Eric Sunshine
2018-07-23 18:22           ` Ben Peart
2018-07-21 13:02     ` Ben Peart
2018-07-23 18:12       ` Junio C Hamano
2018-07-21  6:34   ` [PATCH 2/2] merge-recursive: preserve skip_worktree bit when necessary Elijah Newren
2018-07-23 14:14     ` Ben Peart
2018-07-27 12:59 ` [PATCH v2 0/2] Preserve skip_worktree bit in merges " Ben Peart
2018-07-27 12:59   ` [PATCH v2 1/2] t3507: add a testcase showing failure with sparse checkout Ben Peart
2018-07-27 12:59   ` [PATCH v2 2/2] merge-recursive: preserve skip_worktree bit when necessary Ben Peart
2018-07-27 18:14   ` [PATCH v2 0/2] Preserve skip_worktree bit in merges " Junio C Hamano
2018-07-31 16:11   ` Elijah Newren

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