From 24ba8b70c9965ea40fc1192cf17cd09394cb8350 Mon Sep 17 00:00:00 2001 From: Elijah Newren Date: Sat, 23 Jul 2022 01:53:12 +0000 Subject: merge-resolve: abort if index does not match HEAD As noted in commit 9822175d2b ("Ensure index matches head before invoking merge machinery, round N", 2019-08-17), we have had a very long history of problems with failing to enforce the requirement that index matches HEAD when starting a merge. One of the commits referenced in the long tale of issues arising from lax enforcement of this requirement was commit 55f39cf755 ("merge: fix misleading pre-merge check documentation", 2018-06-30), which tried to document the requirement and noted there were some exceptions. As mentioned in that commit message, the `resolve` strategy was the one strategy that did not have an explicit index matching HEAD check, and the reason it didn't was that I wasn't able to discover any cases where the implementation would fail to catch the problem and abort, and didn't want to introduce unnecessary performance overhead of adding another check. Well, today I discovered a testcase where the implementation does not catch the problem and so an explicit check is needed. Add a testcase that previously would have failed, and update git-merge-resolve.sh to have an explicit check. Note that the code is copied from 3ec62ad9ff ("merge-octopus: abort if index does not match HEAD", 2016-04-09), so that we reuse the same message and avoid making translators need to translate some new message. Signed-off-by: Elijah Newren Signed-off-by: Junio C Hamano --- git-merge-resolve.sh | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'git-merge-resolve.sh') diff --git a/git-merge-resolve.sh b/git-merge-resolve.sh index 343fe7bccd..77e93121bf 100755 --- a/git-merge-resolve.sh +++ b/git-merge-resolve.sh @@ -5,6 +5,16 @@ # # Resolve two trees, using enhanced multi-base read-tree. +. git-sh-setup + +# Abort if index does not match HEAD +if ! git diff-index --quiet --cached HEAD -- +then + gettextln "Error: Your local changes to the following files would be overwritten by merge" + git diff-index --cached --name-only HEAD -- | sed -e 's/^/ /' + exit 2 +fi + # The first parameters up to -- are merge bases; the rest are heads. bases= head= remotes= sep_seen= for arg -- cgit v1.2.3