view tests/test-evolve-issue5832.t @ 3846:f9dad99a90d5

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 for issue 5832 present at https://bz.mercurial-scm.org/show_bug.cgi?id=5832
================================================================================

Setup
=====

  $ cat >> $HGRCPATH <<EOF
  > [phases]
  > publish = False
  > [alias]
  > glog = log -GT "{rev}:{node|short} {desc}\n ({bookmarks}) {phase}"
  > [extensions]
  > EOF
  $ echo "evolve=$(echo $(dirname $TESTDIR))/hgext3rd/evolve/" >> $HGRCPATH

  $ hg init issue5832
  $ cd issue5832

  $ echo base > base
  $ hg ci -Aqm "added base"

  $ echo a > a
  $ hg ci -Aqm "added a"

  $ echo b > b
  $ hg ci -Aqm "added b"

  $ hg up .^^
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo c > c
  $ echo d > d
  $ hg ci -Aqm "added c and d"

  $ hg merge
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m "merge commit"

  $ hg glog
  @    4:b9b387427a53 merge commit
  |\    () draft
  | o  3:9402371b436e added c and d
  | |   () draft
  o |  2:a1da0651488c added b
  | |   () draft
  o |  1:1b24879c5c3c added a
  |/    () draft
  o  0:bde1d2b6b5e5 added base
      () draft

  $ hg up 1b24879c5c3c
  0 files updated, 0 files merged, 3 files removed, 0 files unresolved
  $ echo foo > a
  $ hg amend
  2 new orphan changesets

  $ hg up bde1d2b6b5e5
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo c > c
  $ hg ci -Aqm "added c"
  $ hg up .^
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo d > d
  $ hg ci -Aqm "added d"
  $ hg glog
  @  7:5841d7cf9893 added d
  |   () draft
  | o  6:62fb70414f99 added c
  |/    () draft
  | o  5:7014ec2829cd added a
  |/    () draft
  | *    4:b9b387427a53 merge commit
  | |\    () draft
  +---o  3:9402371b436e added c and d
  | |     () draft
  | *  2:a1da0651488c added b
  | |   () draft
  | x  1:1b24879c5c3c added a
  |/    () draft
  o  0:bde1d2b6b5e5 added base
      () draft

  $ hg prune -r 9402371b436e --succ 62fb70414f99 --succ 5841d7cf9893 --split
  1 changesets pruned

  $ hg glog
  @  7:5841d7cf9893 added d
  |   () draft
  | o  6:62fb70414f99 added c
  |/    () draft
  | o  5:7014ec2829cd added a
  |/    () draft
  | *    4:b9b387427a53 merge commit
  | |\    () draft
  +---x  3:9402371b436e added c and d
  | |     () draft
  | *  2:a1da0651488c added b
  | |   () draft
  | x  1:1b24879c5c3c added a
  |/    () draft
  o  0:bde1d2b6b5e5 added base
      () draft

Checking what evolve is trying to do

  $ hg evolve --dry-run --any --all
  move:[2] added b
  atop:[5] added a
  hg rebase -r a1da0651488c -d 7014ec2829cd
  could not solve instability, ambiguous destination: parent split across two branches

Resolving instability using `hg evolve`

  $ hg evolve --any --all --config ui.interactive=True <<EOF
  > 0
  > EOF
  move:[2] added b
  atop:[5] added a
  move:[4] merge commit
  atop:[8] added b
  ancestor '7235ef625ea3' split over multiple topological branches.
  choose an evolve destination:
  0: [62fb70414f99] added c
  1: [5841d7cf9893] added d
  q: quit the prompt
  enter the index of the revision you want to select: 0
  move:[9] merge commit
  atop:[6] added c
  working directory is now at 28a0775ac832

  $ hg glog
  @    10:28a0775ac832 merge commit
  |\    () draft
  | o  8:2baf8bae7ea4 added b
  | |   () draft
  | | o  7:5841d7cf9893 added d
  | | |   () draft
  o---+  6:62fb70414f99 added c
   / /    () draft
  o /  5:7014ec2829cd added a
  |/    () draft
  o  0:bde1d2b6b5e5 added base
      () draft

  $ cd ..

Test for issue5833 present at https://bz.mercurial-scm.org/show_bug.cgi?id=5833
===============================================================================

  $ hg init issue5833
  $ cd issue5833
  $ echo base > base
  $ hg ci -Aqm "added base"

  $ echo a > a
  $ hg ci -Aqm "added a"

  $ echo b > b
  $ hg ci -Aqm "added b"

  $ hg up .^^
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo c > c
  $ echo d > d
  $ hg ci -Aqm "added c and d"

  $ hg merge
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m "merge commit"

  $ hg glog
  @    4:b9b387427a53 merge commit
  |\    () draft
  | o  3:9402371b436e added c and d
  | |   () draft
  o |  2:a1da0651488c added b
  | |   () draft
  o |  1:1b24879c5c3c added a
  |/    () draft
  o  0:bde1d2b6b5e5 added base
      () draft
 
  $ hg up bde1d2b6b5e5
  0 files updated, 0 files merged, 4 files removed, 0 files unresolved
  $ echo l > l
  $ hg ci -Aqm "added l"
  $ hg grab -r 1b24879c5c3c
  grabbing 1:1b24879c5c3c "added a"
  2 new orphan changesets

  $ hg up bde1d2b6b5e5
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo c > c
  $ hg ci -Aqm "added c"
  $ hg up .^
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo d > d
  $ hg ci -Aqm "added d"

  $ hg glog
  @  8:5841d7cf9893 added d
  |   () draft
  | o  7:62fb70414f99 added c
  |/    () draft
  | o  6:5568b87b1491 added a
  | |   () draft
  | o  5:0a6281e212fe added l
  |/    () draft
  | *    4:b9b387427a53 merge commit
  | |\    () draft
  +---o  3:9402371b436e added c and d
  | |     () draft
  | *  2:a1da0651488c added b
  | |   () draft
  | x  1:1b24879c5c3c added a
  |/    () draft
  o  0:bde1d2b6b5e5 added base
      () draft

  $ hg prune -r 9402371b436e --succ 5841d7cf9893 --succ 62fb70414f99 --split
  1 changesets pruned

  $ hg glog
  @  8:5841d7cf9893 added d
  |   () draft
  | o  7:62fb70414f99 added c
  |/    () draft
  | o  6:5568b87b1491 added a
  | |   () draft
  | o  5:0a6281e212fe added l
  |/    () draft
  | *    4:b9b387427a53 merge commit
  | |\    () draft
  +---x  3:9402371b436e added c and d
  | |     () draft
  | *  2:a1da0651488c added b
  | |   () draft
  | x  1:1b24879c5c3c added a
  |/    () draft
  o  0:bde1d2b6b5e5 added base
      () draft

  $ hg evolve --any --all --dry-run
  move:[2] added b
  atop:[6] added a
  hg rebase -r a1da0651488c -d 5568b87b1491
  could not solve instability, ambiguous destination: parent split across two branches

  $ hg evolve --any --all --config ui.interactive=True <<EOF
  > 1
  > EOF
  move:[2] added b
  atop:[6] added a
  move:[4] merge commit
  atop:[9] added b
  ancestor 'cdf2ea1b9312' split over multiple topological branches.
  choose an evolve destination:
  0: [62fb70414f99] added c
  1: [5841d7cf9893] added d
  q: quit the prompt
  enter the index of the revision you want to select: 1
  move:[10] merge commit
  atop:[8] added d
  working directory is now at 460e6e72b7f9

  $ hg glog
  @    11:460e6e72b7f9 merge commit
  |\    () draft
  | o  9:da76bb7cd904 added b
  | |   () draft
  o |  8:5841d7cf9893 added d
  | |   () draft
  +---o  7:62fb70414f99 added c
  | |     () draft
  | o  6:5568b87b1491 added a
  | |   () draft
  | o  5:0a6281e212fe added l
  |/    () draft
  o  0:bde1d2b6b5e5 added base
      () draft