Martin von Zweigbergk <martinvonz@google.com> [Wed, 23 Sep 2020 16:07:14 -0700] rev 45220
tests: demonstrate crash caused by pinning of non-existent mergestate node
If the mergestate somehow contains a reference to a non-existent node,
it causes most commands to crash since aaeccdb6e654 (repoview: pin
revisions for `local` and `other` when a merge is active,
2020-09-04). This patch adds a test showing that.
Differential Revision: https://phab.mercurial-scm.org/D9077
strip: with --keep, consider all revs "removed" from the wcp (issue6270)
The current code was blink to change from other branches when stripping merges
that are ancestors of the working copy parents.