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.
============================================
Testing obsolescence markers push: Cases B.4
============================================
Mercurial pushes obsolescences markers relevant to the "pushed-set", the set of
all changesets that requested to be "in sync" after the push (even if they are
already on both side).
This test belongs to a series of tests checking such set is properly computed
and applied. This does not tests "obsmarkers" discovery capabilities.
Category B: pruning case
TestCase 4: Pruned changeset on common part of the history
Variants:
# a: explicite push
# b: bare push
B.4 Pruned changeset on common part of history
=============================================
.. {{{
.. ⊗ C
.. | ● B
.. | |
.. | ● A
.. |/
.. ● O
.. }}}
..
.. Marker exist from:
..
.. * C (prune)
..
.. Command run:
..
.. * hg push -r B
.. * hg push
..
.. Expected exchange:
..
.. * prune for C
Setup
-----
$ . $TESTDIR/testlib/exchange-obsmarker-util.sh
initial
$ setuprepos B.4
creating test repo for test case B.4
- pulldest
- main
- pushdest
cd into `main` and proceed with env setup
$ cd main
$ mkcommit A
$ mkcommit B
$ hg phase --public .
$ hg push ../pushdest
pushing to ../pushdest
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 2 changesets with 2 changes to 2 files
$ hg push ../pulldest
pushing to ../pulldest
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 2 changesets with 2 changes to 2 files
$ hg update -q 0
$ mkcommit C
created new head
$ hg prune -qd '0 0' .
$ hg log -G --hidden
x 7f7f229b13a6 (draft): C
|
| o f6fbb35d8ac9 (public): B
| |
| o f5bc6836db60 (public): A
|/
@ a9bdc8b26820 (public): O
$ inspect_obsmarkers
obsstore content
================
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
obshashtree
===========
a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04 4400aae8095ae57b6c8aec3cb0e0b1f6affa2bc1
f5bc6836db60e308a17ba08bf050154ba9c4fad7 f7f3228813861a85df5fd15efa052adfacbf04d5
f6fbb35d8ac958bbe70035e4c789c18471cdc0af 3f79fbe3c760de835dc0cb8f103f639bc7bfcfe3
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 9296ff88911dfe4920e76e60c5a11054949f2fca
obshashrange
============
rev node index size depth obshash
2 f6fbb35d8ac9 0 3 3 000000000000
1 f5bc6836db60 0 2 2 000000000000
0 a9bdc8b26820 0 1 1 4400aae8095a
1 f5bc6836db60 1 1 2 000000000000
2 f6fbb35d8ac9 2 1 3 000000000000
$ cd ..
$ cd ..
$ cp -R B.4 B.4.a
$ cp -R B.4 B.4.b
Actual Test (explicit push version)
-----------------------------------
$ dotest B.4.a O
## Running testcase B.4.a
# testing echange of "O" (a9bdc8b26820)
## initial state
# obstore: main
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
# obstore: pushdest
# obstore: pulldest
## pushing "O" from main to pushdest
pushing to pushdest
searching for changes
no changes found
remote: 1 new obsolescence markers
## post push state
# obstore: main
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
# obstore: pushdest
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
# obstore: pulldest
## pulling "a9bdc8b26820" from main into pulldest
pulling from main
no changes found
1 new obsolescence markers
## post pull state
# obstore: main
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
# obstore: pushdest
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
# obstore: pulldest
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
Actual Test (bare push version)
-----------------------------------
$ dotest B.4.b
## Running testcase B.4.b
## initial state
# obstore: main
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
# obstore: pushdest
# obstore: pulldest
## pushing from main to pushdest
pushing to pushdest
searching for changes
no changes found
remote: 1 new obsolescence markers
## post push state
# obstore: main
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
# obstore: pushdest
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
# obstore: pulldest
## pulling from main into pulldest
pulling from main
searching for changes
no changes found
1 new obsolescence markers
## post pull state
# obstore: main
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
# obstore: pushdest
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}
# obstore: pulldest
7f7f229b13a629a5b20581c6cb723f4e2ca54bed 0 {a9bdc8b26820b1b87d585b82eb0ceb4a2ecdbc04} (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'prune', 'user': 'test'}