discovery: port _postprocessobsolete() changes from evolve, add tests
Let's make this function obsolescence-aware as well. Now we check that
revisions are not obsolete first, and only then check that they are going to be
common after exchange.
The tests make sure that rewriting changesets doesn't confuse head computation.
They rely on experimental.single-head-per-branch feature to show that remote
correctly sees the expected result (i.e. either aborts the push or allows it to
succeed). They are ported from evolve as well.
Differential Revision: https://phab.mercurial-scm.org/D12098
Minimal hgk check
$ echo "[extensions]" >> $HGRCPATH
$ echo "hgk=" >> $HGRCPATH
$ hg init repo
$ cd repo
$ echo a > a
$ hg ci -Am adda
adding a
$ hg debug-cat-file commit 0
tree a0c8bcbbb45c
parent 000000000000
author test 0 0
revision 0
branch default
phase draft
adda
$ echo b > b
$ hg ci -Am addb
adding b
$ hg log -T '{node}\n'
102a90ea7b4a3361e4082ed620918c261189a36a
07f4944404050f47db2e5c5071e0e84e7a27bba9
$ hg debug-diff-tree 07f494440405 102a90ea7b4a
:000000 100664 000000000000 1e88685f5dde N b b
$ hg debug-diff-tree 07f494440405 102a90ea7b4a --patch
diff --git a/b b/b
new file mode 100644
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+b
Ensure that diff-tree output isn't affected by diffopts
$ hg --config diff.noprefix=True debug-diff-tree 07f494440405 102a90ea7b4a
:000000 100664 000000000000 1e88685f5dde N b b
$ hg --config diff.noprefix=True debug-diff-tree --patch 07f494440405 102a90ea7b4a
diff --git a/b b/b
new file mode 100644
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+b
$ cd ..