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).
Set up some configs
$ cat >> $HGRCPATH <<EOF
> [extensions]
> rebase=
> EOF
$ echo "evolve=$(echo $(dirname $TESTDIR))/hgext3rd/evolve/" >> $HGRCPATH
Test listing orphan changesets
$ hg init r2
$ cd r2
$ echo a > a && hg ci -Am a
adding a
$ echo b > b && hg ci -Am b
adding b
$ echo c > c && hg ci -Am c
adding c
$ hg up 0
0 files updated, 0 files merged, 2 files removed, 0 files unresolved
$ echo a >> a && hg ci --amend -m a
2 new orphan changesets
$ hg evolve --list
d2ae7f538514: b
orphan: cb9a9f314b8b (obsolete parent)
177f92b77385: c
orphan: d2ae7f538514 (orphan parent)
$ cd ..
Test listing phase-divergent changesets
$ hg init r3
$ cd r3
$ echo a > a && hg ci -Am a
adding a
$ echo b > b && hg ci --amend -m ab
$ hg phase --public --rev 0 --hidden
1 new phase-divergent changesets
$ hg evolve --list
88cc282e27fc: ab
phase-divergent: cb9a9f314b8b (immutable precursor)
$ cd ..
Test listing content-divergent changesets
$ hg init r1
$ cd r1
$ echo a > a && hg ci -Am a
adding a
$ hg up 0
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ echo b > b && hg ci -Am b
adding b
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo c > c && hg ci -Am c
adding c
created new head
$ hg up 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo d > d && hg ci -Am d
adding d
created new head
$ hg rebase -s 1 -d 2
rebasing 1:d2ae7f538514 "b"
$ hg rebase -s 1 -d 3 --hidden --config experimental.allowdivergence=True
rebasing 1:d2ae7f538514 "b"
2 new content-divergent changesets
$ hg evolve --list
c882616e9d84: b
content-divergent: a922b3733e98 (draft) (precursor d2ae7f538514)
a922b3733e98: b
content-divergent: c882616e9d84 (draft) (precursor d2ae7f538514)
$ hg evolve --list --rev c882616e9d84
c882616e9d84: b
content-divergent: a922b3733e98 (draft) (precursor d2ae7f538514)
$ hg phase -p a922b3733e98
$ hg evolve --list
c882616e9d84: b
content-divergent: a922b3733e98 (public) (precursor d2ae7f538514)
$ cd ..