view tests/test-evolve-noupdate.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.

Testing the `--no-update` flag to `hg evolve` command
=====================================================

There is an `--update` flag to `hg evolve` command which defaults to True. The
`--update` flag updates to the head of the evolved revisions. If you dont want
to change your working directory or update your working directory to its
sucessor after hg evolve, `hg evolve --no-update` is the thing for you.

This patch tests that flag.

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

Making sure we stay where we were is current wdir parent is not obsoleted
--------------------------------------------------------------------------

  $ hg up .^^
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ echo bar > b
  $ hg amend
  2 new orphan changesets
  $ hg glog
  @  5:7ed0642d644b added b
  |   () draft
  | *  4:c41c793e0ef1 added d
  | |   () draft
  | *  3:ca1b80f7960a added c
  | |   () draft
  | x  2:b1661037fa25 added b
  |/    () draft
  o  1:c7586e2a9264 added a
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft

There is 'working directory is now at' message because it didnt changed
  $ hg evolve --all --no-update
  move:[3] added c
  atop:[5] added b
  move:[4] added d
  atop:[6] added c

  $ hg glog
  o  7:b6b20b8eefdc added d
  |   () draft
  o  6:7c46f743e62f added c
  |   () draft
  @  5:7ed0642d644b added b
  |   () draft
  o  1:c7586e2a9264 added a
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft

Updating to successor when working directory parent is obsoleted by evolution
-----------------------------------------------------------------------------

  $ hg prev
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  [1] added a
  $ echo bar > a
  $ hg amend
  3 new orphan changesets
  $ hg up 7ed0642d644b
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg glog
  o  8:3d41537b44ca added a
  |   () draft
  | *  7:b6b20b8eefdc added d
  | |   () draft
  | *  6:7c46f743e62f added c
  | |   () draft
  | @  5:7ed0642d644b added b
  | |   () draft
  | x  1:c7586e2a9264 added a
  |/    () draft
  o  0:8fa14d15e168 added hgignore
      () draft

  $ hg evolve --all --any --no-update
  move:[5] added b
  atop:[8] added a
  move:[6] added c
  atop:[9] added b
  move:[7] added d
  atop:[10] added c
  working directory is now at 12c720cb3782

  $ hg glog
  o  11:a74d9f22ba3f added d
  |   () draft
  o  10:958f5155e8cd added c
  |   () draft
  @  9:12c720cb3782 added b
  |   () draft
  o  8:3d41537b44ca added a
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft