view tests/test-evolve-orphan-split.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 resolution of orphans by `hg evolve` where an obsolete changeset has
multiple successors **

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

Repo Setup

  $ hg init repo
  $ cd repo
  $ echo ".*\.orig" > .hgignore
  $ hg add .hgignore
  $ hg ci -m "added hgignore"

An orphan changeset with parent got splitted
--------------------------------------------

  $ for ch in a b c; do echo foo > $ch; done;

  $ hg add a b
  $ hg ci -m "added a and b"
  $ hg add c
  $ hg ci -m "added c"

  $ hg glog
  @  2:86e1ebf1ca61 added c
  |   () draft
  o  1:d0ddb614efbd added a and b
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft

  $ hg split -r 1 <<EOF
  > y
  > y
  > n
  > y
  > EOF
  0 files updated, 0 files merged, 3 files removed, 0 files unresolved
  adding a
  adding b
  diff --git a/a b/a
  new file mode 100644
  examine changes to 'a'? [Ynesfdaq?] y
  
  @@ -0,0 +1,1 @@
  +foo
  record change 1/2 to 'a'? [Ynesfdaq?] y
  
  diff --git a/b b/b
  new file mode 100644
  examine changes to 'b'? [Ynesfdaq?] n
  
  created new head
  Done splitting? [yN] y
  1 new orphan changesets

  $ hg glog
  @  4:8b179cffc81c added a and b
  |   () draft
  o  3:bd3735d4dab0 added a and b
  |   () draft
  | *  2:86e1ebf1ca61 added c
  | |   () draft
  | x  1:d0ddb614efbd added a and b
  |/    () draft
  o  0:8fa14d15e168 added hgignore
      () draft

  $ hg evolve
  move:[2] added c
  atop:[4] added a and b
  working directory is now at af13f0560b31

  $ hg glog
  @  5:af13f0560b31 added c
  |   () draft
  o  4:8b179cffc81c added a and b
  |   () draft
  o  3:bd3735d4dab0 added a and b
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft

When the successors does not form a linear chain and are multiple heads
-----------------------------------------------------------------------

  $ hg fold -r .^^::. --exact -m "added a b c"
  3 changesets folded
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg glog
  @  6:f89e4764f2ed added a b c
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft
  $ echo foo > d
  $ hg ci -Aqm "added d"

  $ hg glog
  @  7:d48a30875f01 added d
  |   () draft
  o  6:f89e4764f2ed added a b c
  |   () draft
  o  0:8fa14d15e168 added hgignore
      () draft
  $ hg prev
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  [6] added a b c
  $ hg split -r . <<EOF
  > y
  > n
  > y
  > y
  > y
  > y
  > y
  > EOF
  0 files updated, 0 files merged, 3 files removed, 0 files unresolved
  adding a
  adding b
  adding c
  diff --git a/a b/a
  new file mode 100644
  examine changes to 'a'? [Ynesfdaq?] y
  
  @@ -0,0 +1,1 @@
  +foo
  record change 1/3 to 'a'? [Ynesfdaq?] n
  
  diff --git a/b b/b
  new file mode 100644
  examine changes to 'b'? [Ynesfdaq?] y
  
  @@ -0,0 +1,1 @@
  +foo
  record change 2/3 to 'b'? [Ynesfdaq?] y
  
  diff --git a/c b/c
  new file mode 100644
  examine changes to 'c'? [Ynesfdaq?] y
  
  @@ -0,0 +1,1 @@
  +foo
  record change 3/3 to 'c'? [Ynesfdaq?] y
  
  created new head
  Done splitting? [yN] y
  1 new orphan changesets

  $ hg glog
  @  9:c0fbf8aaf6c4 added a b c
  |   () draft
  o  8:f2632392aefe added a b c
  |   () draft
  | *  7:d48a30875f01 added d
  | |   () draft
  | x  6:f89e4764f2ed added a b c
  |/    () draft
  o  0:8fa14d15e168 added hgignore
      () draft

  $ hg rebase -r . -d 8fa14d15e168
  rebasing 9:c0fbf8aaf6c4 "added a b c" (tip)
  $ hg glog
  @  10:7f87764e5b64 added a b c
  |   () draft
  | o  8:f2632392aefe added a b c
  |/    () draft
  | *  7:d48a30875f01 added d
  | |   () draft
  | x  6:f89e4764f2ed added a b c
  |/    () draft
  o  0:8fa14d15e168 added hgignore
      () draft

  $ hg evolve --dry-run <<EOF
  > 0
  > EOF
  ancestor 'd48a30875f01' split over multiple topological branches.
  choose an evolve destination:
  0: [f2632392aefe] added a b c
  1: [7f87764e5b64] added a b c
  q: quit the prompt
  enter the index of the revision you want to select: 0
  move:[7] added d
  atop:[8] added a b c
  hg rebase -r d48a30875f01 -d f2632392aefe

  $ hg evolve --dry-run <<EOF
  > 1
  > EOF
  ancestor 'd48a30875f01' split over multiple topological branches.
  choose an evolve destination:
  0: [f2632392aefe] added a b c
  1: [7f87764e5b64] added a b c
  q: quit the prompt
  enter the index of the revision you want to select: 1
  move:[7] added d
  atop:[10] added a b c
  hg rebase -r d48a30875f01 -d 7f87764e5b64

Testing the interactive prompt with invalid values first
(this should move its own test file when we use it at multiple places)

  $ hg evolve --all <<EOF
  > foo
  > EOF
  ancestor 'd48a30875f01' split over multiple topological branches.
  choose an evolve destination:
  0: [f2632392aefe] added a b c
  1: [7f87764e5b64] added a b c
  q: quit the prompt
  enter the index of the revision you want to select: foo
  invalid value 'foo' entered for index
  could not solve instability, ambiguous destination: parent split across two branches

  $ hg evolve --all <<EOF
  > 4
  > EOF
  ancestor 'd48a30875f01' split over multiple topological branches.
  choose an evolve destination:
  0: [f2632392aefe] added a b c
  1: [7f87764e5b64] added a b c
  q: quit the prompt
  enter the index of the revision you want to select: 4
  invalid value '4' entered for index
  could not solve instability, ambiguous destination: parent split across two branches

  $ hg evolve --all <<EOF
  > -1
  > EOF
  ancestor 'd48a30875f01' split over multiple topological branches.
  choose an evolve destination:
  0: [f2632392aefe] added a b c
  1: [7f87764e5b64] added a b c
  q: quit the prompt
  enter the index of the revision you want to select: -1
  invalid value '-1' entered for index
  could not solve instability, ambiguous destination: parent split across two branches

  $ hg evolve --all <<EOF
  > q
  > EOF
  ancestor 'd48a30875f01' split over multiple topological branches.
  choose an evolve destination:
  0: [f2632392aefe] added a b c
  1: [7f87764e5b64] added a b c
  q: quit the prompt
  enter the index of the revision you want to select: q
  could not solve instability, ambiguous destination: parent split across two branches

Doing the evolve with the interactive prompt

  $ hg evolve --all <<EOF
  > 1
  > EOF
  ancestor 'd48a30875f01' split over multiple topological branches.
  choose an evolve destination:
  0: [f2632392aefe] added a b c
  1: [7f87764e5b64] added a b c
  q: quit the prompt
  enter the index of the revision you want to select: 1
  move:[7] added d
  atop:[10] added a b c
  working directory is now at 1c6caa7c902a