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 <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We want to make sure that people who copy & paste code would see
fewer instances of "git-foo". The use of these dashed forms have
been discouraged since v1.6.0 days.
Signed-off-by: Michael Forney <mforney@mforney.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A minor fix that eliminates usage of "2>/dev/null" when --quiet or
-q has already been implemented.
Signed-off-by: Dan Loewenherz <daniel.loewenherz@yale.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Comments in both these strategies refer to the wrong number
of remotes
Signed-off-by: Tom Clarke <tom@u2i.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A new flag --aggressive resolves what we traditionally resolved
with external git-merge-one-file inside index while read-tree
3-way merge works.
git-merge-octopus and git-merge-resolve use this flag before
running git-merge-index with git-merge-one-file.
Signed-off-by: Junio C Hamano <junkio@cox.net>
Let the merge strategies handle the base less case if they are able to
do it. It also fixes git-resolve.sh to die if no common ancestors
exists, instead of doing the wrong thing. Furthermore, it contains a
small independent fix for git-merge.sh and a fix for a base less code
path in gitMergeCommon.py.
With this it's possible to use
git merge -s recursive 'merge message' A B
to do a base less merge of A and B.
[jc: Thanks Fredrik for fixing the brown-paper-bag in git-merge.
I fixed a small typo in git-merge-resolve fix; 'test' equality
check is spelled with single equal sign -- C-style double equal
sign is bashism.]
Signed-off-by: Fredrik Kuivinen <freku045@student.liu.se>
Signed-off-by: Junio C Hamano <junkio@cox.net>
The new command 'git merge' takes the current head and one or more
remote heads, with the commit log message for the automated case.
If the heads being merged are simple fast-forwards, it acts the
same way as the current 'git resolve'. Otherwise, it tries
different merge strategies and takes the result from the one that
succeeded auto-merging, if there is any.
If no merge strategy succeeds auto-merging, their results are
evaluated for number of paths needed for hand resolving, and the
one with the least number of such paths is left in the working
tree. The user is asked to resolve them by hand and make a
commit manually.
The calling convention from the 'git merge' driver to merge
strategy programs is very simple:
- A strategy program is to be called 'git-merge-<strategy>'.
- They take input of this form:
<common1> <common2> ... '--' <head> <remote1> <remote2>...
That is, one or more the common ancestors, double dash, the
current head, and one or more remote heads being merged into
the current branch.
- Before a strategy program is called, the working tree is
matched to the current <head>.
- The strategy program exits with status code 0 when it
successfully auto-merges the given heads. It should do
update-cache for all the merged paths when it does so -- the
index file will be used to record the merge result as a
commit by the driver.
- The strategy program exits with status code 1 when it leaves
conflicts behind. It should do update-cache for all the
merged paths that it successfully auto-merged, and leave the
cache entry in the index file as the same as <head> for paths
it could not auto-merge, and leave its best-effort result
with conflict markers in the working tree when it does so.
- The strategy program exists with status code other than 0 or
1 if it does not handle the given merge at all.
As examples, this commit comes with merge strategies based on
'git resolve' and 'git octopus'.
Signed-off-by: Junio C Hamano <junkio@cox.net>
