evolve: handle relocation during divergence resolution producing no changes
When resolving divergence and the two divergent commits have different
parents, we start by rebasing one of them to have the same parent as
the other. That step can result in no changes to commit. When it does,
we would crash with a TypeError before this patch.
This patch fixes it by instead creating an empty commit in that
scenario. The existing code then continues to attempt to merge it,
which produces no changes, and no commit is created on top. The other
side of the divergence is marked as successor as usual, so orphans
from the side that became empty will be evolved to the right place
(see test).
=========================================
Testing single head enforcement: Case A-1
=========================================
A repository is set to only accept a single head per name (typically named
branch). However, obsolete changesets can make this enforcement more
complicated, because they can be kept visible by other changeset on other
branch.
This case is part of a series of tests checking this behavior.
Category A: Involving obsolescence
TestCase 1: obsoleting a merge reveal two heads
.. old-state:
..
.. * 3 changeset changeset on topic X (2 on their own branch + 1 merge)
.. * 1 changeset on topic Y (children of the merge)
..
.. new-state:
..
.. * 2 changeset changeset on topic X (merge is obsolete) each a head
.. * 1 changeset on topic Y keeping the merge visible
..
.. expected-result:
..
.. * 2 heads detected (because we skip the merge).
..
.. graph-summary:
..
.. D ● (topic-Y)
.. |
.. C ● (topic-Y)
.. |
.. M ⊗ (topic-X)
.. |\
.. A ● ● B (topic-X)
.. |/
.. ●
$ . $TESTDIR/testlib/topic_setup.sh
$ . $TESTDIR/testlib/push-checkheads-util.sh
Test setup
----------
$ mkdir B5
$ cd B5
$ setuprepos single-head
creating basic server and client repo
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ cd client
$ hg topic -r . topic-X
switching to topic topic-X
changed topic on 1 changesets to "topic-X"
$ hg strip --config extensions.strip= --hidden 'hidden()' --no-backup # clean old A0
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg topic topic-X
marked working directory as topic: topic-X
$ mkcommit B0
$ hg merge
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -m 'M0'
$ hg topic topic-Y
$ mkcommit C0
active topic 'topic-Y' grew its first changeset
(see 'hg help topics' for more information)
$ hg push --new-branch
pushing to $TESTTMP/B5/server
searching for changes
adding changesets
adding manifests
adding file changes
added 4 changesets with 2 changes to 3 files (+1 heads)
1 new obsolescence markers
obsoleted 1 changesets
$ hg up 0
0 files updated, 0 files merged, 3 files removed, 0 files unresolved
$ mkcommit A1
$ mkcommit B1
$ hg debugobsolete `getid "desc(M0)"` --record-parents
1 new obsolescence markers
obsoleted 1 changesets
1 new orphan changesets
$ hg log -G --hidden
@ 262c8c798096 [default] (draft): B1
|
o f6082bc4ffef [default] (draft): A1
|
| * 339fd31549ed [default:topic-Y] (draft): C0
| |
| x 33b3d4185449 [default:topic-X] (draft): M0
| |\
+---o d3826ff42cf7 [default:topic-X] (draft): B0
| |
| o 5a47a98cd8e5 [default:topic-X] (draft): A0
|/
o 1e4be0697311 [default] (public): root
Actual testing
--------------
(force push to make sure we get the changeset on the remote)
$ hg push -r 'desc("C0")' --force
pushing to $TESTTMP/B5/server
searching for changes
no changes found
transaction abort!
rollback completed
abort: rejecting multiple heads on branch "default:topic-X"
(2 heads: 5a47a98cd8e5 d3826ff42cf7)
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