evolve: create a new commit instead of amending one of the divergents
This patch changes the behavior of evolve command while resolving
content-divergence to create a new commit instead of amending one of the
divergent ones.
In past, I have made this change, backed out this change and now today again I
am doing this change, so let's dive in some history.
Using cmdrewrite.amend() was never a good option as that requires hack to delete
the evolvestate and also gives us less control over things. We can't make the
commit on top of different parents as that of content-divergent ones. Due to all
these, I first made this change to create a new commit instead of amending one.
But, after few days, there was flakiness observed in the tests and turned out
that we need to do some dirstate dance as repo.dirstate.setparents() does not
always fix the dirstate. That flakiness was a blocker for progress at that time
and we decided to switch to amend back so that we can have things working with
some hacks and we can later fix the implementation part.
Now, yesterday while tackling resolving content-divergence of a stack which is
as follows:
C1 C2
| |
B1 B2
| |
A1 A2
\/
base
where, A1-A2, B1-B2, C1-C2 are content-divergent with each other. Now we can
resolve A1-A2 very well because they have the same parent and let's say that
resolution leads to A3.
Now, we want to resolve B1-B2 and make the new resolution commit on top of A3 so
that we can end up something like:
C3
|
B3
|
A3
|
base
however, amending one of the divergent changesets, it's not possible to create a
commit on a different parent like A3 here without some relocation. We should
prevent relocation as that may leads to some conflicts and should change the
parent before committing.
So, looking ahead, we can't move with using amend as still using that we will
need some relocation hacks making code ugly and prone to bad behaviors, bugs.
Let's change back to creating a new commit so that we can move forward in a good
way.
About repo.dirstate.setparents() not setting the dirstate, I have researched
yesterday night about how we can do that and found out that we can use
cmdrewrite._uncommitdirstate() here. Expect upcoming patches to improve the
documentation of that function.
There are lot of test changes because of change in hash but there is no behavior
change. The only behavior change is in test-evolve-abort-contentdiv.t which is
nice because creating a new commit helps us in stripping that while aborting.
We have a lot of testing of content-divergence and no behavior change gives
enough confidence for making this change.
I reviewed the patch carefully to make sure there is no behavior change and I
suggest reviewer to do the same.
=====================
Test workflow options
=====================
$ . "$TESTDIR/testlib/topic_setup.sh"
$ . "$TESTDIR/testlib/common.sh"
Test single head enforcing - Setup
=============================================
$ hg init single-head-server
$ cd single-head-server
$ cat <<EOF >> .hg/hgrc
> [phases]
> publish = no
> [experimental]
> enforce-single-head = yes
> evolution = all
> EOF
$ mkcommit ROOT
$ mkcommit c_dA0
$ cd ..
$ hg clone single-head-server client
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
Test single head enforcing - with branch only
---------------------------------------------
$ cd client
continuing the current defaultbranch
$ mkcommit c_dB0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
creating a new branch
$ hg up 'desc("ROOT")'
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ hg branch branch_A
marked working directory as branch branch_A
(branches are permanent and global, did you want a bookmark?)
$ mkcommit c_aC0
$ hg push --new-branch
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
Create a new head on the default branch
$ hg up 'desc("c_dA0")'
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkcommit c_dD0
created new head
(consider using topic for lightweight branches. See 'hg help topic')
$ hg push -f
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
transaction abort!
rollback completed
abort: 2 heads on "default"
(286d02a6e2a2, 9bf953aa81f6)
[255]
remerge them
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ mkcommit c_dE0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
Test single head enforcing - with topic
---------------------------------------
pushing a new topic
$ hg topic foo
marked working directory as topic: foo
$ mkcommit c_dF0
active topic 'foo' grew its first changeset
(see 'hg help topics' for more information)
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
pushing a new topo branch (with a topic)
$ hg up 'desc("c_dD0")'
0 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ hg topic bar
marked working directory as topic: bar
$ mkcommit c_dG0
active topic 'bar' grew its first changeset
(see 'hg help topics' for more information)
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
detect multiple heads on the topic
$ mkcommit c_dH0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
$ hg up 'desc("c_dG0")'
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ mkcommit c_dI0
$ hg push -f
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files (+1 heads)
transaction abort!
rollback completed
abort: 2 heads on "default:bar"
(5194f5dcd542, 48a01453c1c5)
[255]
merge works fine
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ mkcommit c_dJ0
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 2 files
Test single head enforcing - by phase move
------------------------------------------
$ hg -R ../single-head-server phase --public 'desc("c_dJ0")'
abort: 2 heads on "default"
(6ed1df20edb1, 678bca4de98c)
[255]
Test single head enforcing - after rewrite
------------------------------------------
$ hg up foo
switching to topic foo
3 files updated, 0 files merged, 4 files removed, 0 files unresolved
$ hg commit --amend -m c_dF1
$ hg push
pushing to $TESTTMP/single-head-server
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 1 files (+1 heads)
1 new obsolescence markers
obsoleted 1 changesets