Instead of waiting until we record the parents of resulting merge, reduce
redundant parents (including our HEAD) immediately after reading them.
The change to t7602 illustrates the essence of the effect of this change.
The octopus merge strategy used to be fed with redundant commits only to
discard them as "up-to-date", but we no longer feed such redundant commits
to it and the affected test degenerates to a regular two-head merge.
And obviously the known-to-be-broken test in t6028 is now fixed.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This happens when git merge is run to merge multiple commits that are
descendants of current HEAD (or are HEAD). We've hit this while updating
master to origin/master but accidentaly we called (while being on master):
$ git merge master origin/master
Here is a minimal testcase:
$ git init a && cd a
$ echo a >a && git add a
$ git commit -minitial
$ echo b >a && git add a
$ git commit -msecond
$ git checkout master^
$ git merge master master
Fast-forwarding to: master
Already up-to-date with master
Merge made by the 'octopus' strategy.
a | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
$ git cat-file commit HEAD
tree eebfed94e75e7760540d1485c740902590a00332
parent bd679e85202280b263e20a57639a142fa14c2c64
author Michał Kiedrowicz <michal.kiedrowicz@gmail.com> 1329132996 +0100
committer Michał Kiedrowicz <michal.kiedrowicz@gmail.com> 1329132996 +0100
Merge branches 'master' and 'master' into HEAD
Signed-off-by: Michał Kiedrowicz <michal.kiedrowicz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This clarifies the logic to omit fast-forward check and omit
trivial merge before running the specified strategy.
The "index_merge" variable started out as a flag to say "do not
do anything clever", but when recursive was changed to skip the
trivial merge, the semantics were changed and the variable alone
does not make sense anymore.
This splits the variable into two, allow_fast_forward (which is
almost always true, and avoids making a merge commit when the
other commit is a descendant of our branch, but is set to false
for ours and subtree) and allow_trivial_merge (which is false
for ours, recursive and subtree).
Unlike the earlier implementation, the "ours" strategy allows an
up-to-date condition. When we are up-to-date, the result will
be our commit, and by definition, we will have our tree as the
result.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
