view tests/test-divergent.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 the resolution of divergence

  $ cat >> $HGRCPATH <<EOF
  > [defaults]
  > amend=-d "0 0"
  > fold=-d "0 0"
  > [web]
  > push_ssl = false
  > allow_push = *
  > [phases]
  > publish = False
  > [diff]
  > git = 1
  > unified = 0
  > [ui]
  > logtemplate = {rev}:{node|short}@{branch}({phase}) {desc|firstline} [{troubles}]\n
  > [extensions]
  > EOF
  $ echo "evolve=$(echo $(dirname $TESTDIR))/hgext3rd/evolve/" >> $HGRCPATH
  $ mkcommit() {
  >    echo "$1" > "$1"
  >    hg add "$1"
  >    hg ci -m "add $1"
  > }

  $ mkcommits() {
  >   for i in $@; do mkcommit $i ; done
  > }

Basic test of divergence: two divergent changesets with the same parents
With --all --any we dedupe the divergent and solve the divergence once

  $ hg init test1
  $ cd test1
  $ echo a > a
  $ hg ci -Aqm "added a"
  $ echo b > b
  $ hg ci -Aqm "added b"

  $ hg up .^
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo bdivergent > bdivergent1
  $ hg ci -Am "divergent"
  adding bdivergent1
  created new head

  $ hg up .^
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo bdivergent > bdivergent2
  $ hg ci -Am "divergent"
  adding bdivergent2
  created new head

  $ hg prune -s 8374d2ddc3a4 "desc('added b')"
  1 changesets pruned
  $ hg prune -s 593c57f2117e "desc('added b')" --hidden
  1 changesets pruned
  2 new content-divergent changesets

  $ hg log -G
  @  3:8374d2ddc3a4@default(draft) divergent [content-divergent]
  |
  | *  2:593c57f2117e@default(draft) divergent [content-divergent]
  |/
  o  0:9092f1db7931@default(draft) added a []
  

  $ hg evolve --all --any --content-divergent
  merge:[2] divergent
  with: [3] divergent
  base: [1] added b
  updating to "local" side of the conflict: 593c57f2117e
  merging "other" content-divergent changeset '8374d2ddc3a4'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  working directory is now at 45bf1312f454
  $ hg log -G
  @  4:45bf1312f454@default(draft) divergent []
  |
  o  0:9092f1db7931@default(draft) added a []
  
Test divergence resolution when it yields to an empty commit (issue4950)
cdivergent2 contains the same content than cdivergent1 and they are divergent
versions of the revision _c

  $ hg up .^
  0 files updated, 0 files merged, 2 files removed, 0 files unresolved
  $ mkcommit _c
  created new head

  $ hg up .^
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ mkcommit cdivergent1
  created new head

  $ hg up .^
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo "cdivergent1" > cdivergent1
  $ hg add cdivergent1
  $ hg ci -m "add _c"
  created new head

  $ hg log -G
  @  7:b2ae71172042@default(draft) add _c []
  |
  | o  6:e3ff64ce8d4c@default(draft) add cdivergent1 []
  |/
  | o  5:48819a835615@default(draft) add _c []
  |/
  | o  4:45bf1312f454@default(draft) divergent []
  |/
  o  0:9092f1db7931@default(draft) added a []
  

  $ hg prune -s b2ae71172042 48819a835615
  1 changesets pruned
  $ hg prune -s e3ff64ce8d4c 48819a835615 --hidden
  1 changesets pruned
  2 new content-divergent changesets

  $ hg log -G
  @  7:b2ae71172042@default(draft) add _c [content-divergent]
  |
  | *  6:e3ff64ce8d4c@default(draft) add cdivergent1 [content-divergent]
  |/
  | o  4:45bf1312f454@default(draft) divergent []
  |/
  o  0:9092f1db7931@default(draft) added a []
  
  $ hg evolve --all --any --content-divergent
  merge:[6] add cdivergent1
  with: [7] add _c
  base: [5] add _c
  updating to "local" side of the conflict: e3ff64ce8d4c
  merging "other" content-divergent changeset 'b2ae71172042'
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  nothing changed
  working directory is now at e3ff64ce8d4c

  $ cd ..

Test None docstring issue of evolve divergent, which caused hg crush

  $ hg init test2
  $ cd test2
  $ mkcommits _a _b

  $ hg up .^
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo bdivergent > bdivergent11
  $ hg ci -Am "bdivergent"
  adding bdivergent11
  created new head

  $ hg up .^
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo bdivergent > bdivergent22
  $ hg ci -Am "bdivergent"
  adding bdivergent22
  created new head

  $ hg log -G
  @  3:6b096fb45070@default(draft) bdivergent []
  |
  | o  2:05a6b6a9e633@default(draft) bdivergent []
  |/
  | o  1:37445b16603b@default(draft) add _b []
  |/
  o  0:135f39f4bd78@default(draft) add _a []
  

  $ hg prune -s 6b096fb45070 37445b16603b
  1 changesets pruned
  $ hg prune -s 05a6b6a9e633 37445b16603b --hidden
  1 changesets pruned
  2 new content-divergent changesets
  $ hg log -G
  @  3:6b096fb45070@default(draft) bdivergent [content-divergent]
  |
  | *  2:05a6b6a9e633@default(draft) bdivergent [content-divergent]
  |/
  o  0:135f39f4bd78@default(draft) add _a []
  

  $ cat >$TESTTMP/test_extension.py  << EOF
  > from mercurial import merge
  > origupdate = merge.update
  > def newupdate(*args, **kwargs):
  >   return origupdate(*args, **kwargs)
  > merge.update = newupdate
  > EOF
  $ cat >> $HGRCPATH << EOF
  > [extensions]
  > testextension=$TESTTMP/test_extension.py
  > EOF
  $ hg evolve --all
  nothing to evolve on current working copy parent
  (do you want to use --content-divergent)
  [2]
  $ hg evolve --content-divergent
  merge:[3] bdivergent
  with: [2] bdivergent
  base: [1] add _b
  merging "other" content-divergent changeset '05a6b6a9e633'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  working directory is now at 73ff357d3975

  $ cd ..