view tests/test-evolve-stop-contentdiv.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.

Tests for the --stop flag for `hg evolve` command while resolving content-divergence
==================================================================================

The `--stop` flag stops the interrupted evolution and delete the state file so
user can do other things and comeback and do evolution later on

This is testing cases when `hg evolve` command is doing content-divergence resolution.

Setup
=====

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

  $ hg init stoprepo
  $ cd stoprepo
  $ echo ".*\.orig" > .hgignore
  $ hg add .hgignore
  $ hg ci -m "added hgignore"
  $ for ch in a b c d; do echo foo > $ch; hg add $ch; hg ci -qm "added "$ch; done;

  $ hg glog
  @  4:c41c793e0ef1 added d
  |   () draft
  o  3:ca1b80f7960a added c
  |   () draft
  o  2:b1661037fa25 added b
  |   () draft
  o  1:c7586e2a9264 added a
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft

Creating content divergence, resolution of which will lead to conflicts
-----------------------------------------------------------------------

  $ echo bar > d
  $ hg amend

  $ hg up c41c793e0ef1 --hidden
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset c41c793e0ef1
  (hidden revision 'c41c793e0ef1' was rewritten as: e49523854bc8)
  working directory parent is obsolete! (c41c793e0ef1)
  (use 'hg evolve' to update to its successor: e49523854bc8)

  $ echo foobar > d
  $ hg amend
  2 new content-divergent changesets
  $ hg glog --hidden
  @  6:9c1631e352d9 added d
  |   () draft
  | *  5:e49523854bc8 added d
  |/    () draft
  | x  4:c41c793e0ef1 added d
  |/    () draft
  o  3:ca1b80f7960a added c
  |   () draft
  o  2:b1661037fa25 added b
  |   () draft
  o  1:c7586e2a9264 added a
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft

  $ hg evolve --content-divergent
  merge:[6] added d
  with: [5] added d
  base: [4] added d
  merging "other" content-divergent changeset 'e49523854bc8'
  merging d
  warning: conflicts while merging d! (edit, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  abort: fix conflicts and see `hg help evolve.interrupted`
  [255]

  $ hg evolve --stop
  stopped the interrupted evolve
  working directory is now at 9c1631e352d9

  $ hg glog --hidden
  @  6:9c1631e352d9 added d
  |   () draft
  | *  5:e49523854bc8 added d
  |/    () draft
  | x  4:c41c793e0ef1 added d
  |/    () draft
  o  3:ca1b80f7960a added c
  |   () draft
  o  2:b1661037fa25 added b
  |   () draft
  o  1:c7586e2a9264 added a
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft

Content divergence with parent change which will result in conflicts while
merging
---------------------------------------------------------------------------

  $ hg rebase -r . -d .^^^ --config extensions.rebase=
  rebasing 6:9c1631e352d9 "added d" (tip)

  $ hg glog
  @  7:517d4375cb72 added d
  |   () draft
  | *  5:e49523854bc8 added d
  | |   () draft
  | o  3:ca1b80f7960a added c
  | |   () draft
  | o  2:b1661037fa25 added b
  |/    () draft
  o  1:c7586e2a9264 added a
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft

  $ hg evolve --content-divergent
  merge:[5] added d
  with: [7] added d
  base: [4] added d
  rebasing "other" content-divergent changeset 517d4375cb72 on ca1b80f7960a
  updating to "local" side of the conflict: e49523854bc8
  merging "other" content-divergent changeset '606ad96040fc'
  merging d
  warning: conflicts while merging d! (edit, then use 'hg resolve --mark')
  0 files updated, 0 files merged, 0 files removed, 1 files unresolved
  abort: fix conflicts and see `hg help evolve.interrupted`
  [255]

  $ hg evolve --stop
  stopped the interrupted evolve
  working directory is now at 517d4375cb72

  $ hg glog
  @  7:517d4375cb72 added d
  |   () draft
  | *  5:e49523854bc8 added d
  | |   () draft
  | o  3:ca1b80f7960a added c
  | |   () draft
  | o  2:b1661037fa25 added b
  |/    () draft
  o  1:c7586e2a9264 added a
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft

Content-divergence with parent-change which will result in conflicts while
relocation
---------------------------------------------------------------------------

  $ echo babar > c
  $ hg add c
  $ hg amend
  $ hg glog
  @  8:8fd1c4bd144c added d
  |   () draft
  | *  5:e49523854bc8 added d
  | |   () draft
  | o  3:ca1b80f7960a added c
  | |   () draft
  | o  2:b1661037fa25 added b
  |/    () draft
  o  1:c7586e2a9264 added a
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft

  $ hg evolve --content-divergent
  merge:[5] added d
  with: [8] added d
  base: [4] added d
  rebasing "other" content-divergent changeset 8fd1c4bd144c on ca1b80f7960a
  merging c
  warning: conflicts while merging c! (edit, then use 'hg resolve --mark')
  abort: unresolved merge conflicts (see hg help resolve)
  [255]

  $ hg diff
  diff -r ca1b80f7960a c
  --- a/c	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,1 +1,5 @@
  +<<<<<<< destination: ca1b80f7960a - test: added c
   foo
  +=======
  +babar
  +>>>>>>> evolving:    8fd1c4bd144c - test: added d
  diff -r ca1b80f7960a d
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/d	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foobar

  $ hg evolve --stop
  stopped the interrupted evolve
  working directory is now at ca1b80f7960a

XXX: we should have preserved the wdir to be at rev 8
  $ hg glog
  *  8:8fd1c4bd144c added d
  |   () draft
  | *  5:e49523854bc8 added d
  | |   () draft
  | @  3:ca1b80f7960a added c
  | |   () draft
  | o  2:b1661037fa25 added b
  |/    () draft
  o  1:c7586e2a9264 added a
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft