bookmark: add a test for a race condition on push Bookmark pointing to unknown nodes are ignored. Later these ignored bookmarks are dropped when writing the file back on disk. On paper, this behavior should be fine, but with the current implementation, it can lead to unexpected bookmark deletions. In theory, to make sure writer as a consistent view, taking the lock also invalidate bookmark data we already loaded into memory. However this invalidation is incomplete. The data are stored in a `filecache` that preserve them if the bookmark related file are untouched. In practice, the bookmark data in memory also depends of the changelog content, because of the step checking if the bookmarks refers to a node known to the changelog. So if the bookmark data were loaded from an up to date bookmark file but filtered with an outdated changelog file this go undetected. This condition is fairly specific, but can occurs very often in practice. We introduce a test recreating the situation. The test comes in an independant changeset to show it actually reproduce the situation. The fix will come soon after. A large share of the initial investigation of this race condition was made by Valentin Gatien-Baron <valentin.gatienbaron@gmail.com>.

test: properly gate a zstd section This part of the test can't run if zstd is not available. This was caught by --pure test (who don't support zstd).

test: update test for expected test output In 1fac9b931d46 as new test session was introduced. It did not take in account some part that only ran for pure. The test is now fixed.

log: flag topo-sorted set as such This isn't required right now, but revs.istopo() should return True.

copies: fix duplicatecopies() with overlay context The reasoning for this check is in 78d760aa3607 (duplicatecopies: do not mark items not in the dirstate as copies, 2013-03-28). The check was then moved to workingfilectx in 754b5117622f (context: add workingfilectx.markcopied, 2017-10-15) and no corresponding check was added later when overlayworkingfilectx was added. Rather than adding the check there, this patch adds a more generic check on the callers side and removes the check in workingfilectx.markcopied(). Differential Revision: https://phab.mercurial-scm.org/D6380

tests: demonstrate crash when rebasing across copy with --collapse As reported by timeless. Differential Revision: https://phab.mercurial-scm.org/D6379

exthelper: add some semi-useful trace logs It'd be nice to make the trace functions a little better-named in the output, but I'm not sure how much better we can do without overhead. This at least lets you see if a single reposetup function is eating all the time or if it's spread over all of them. I needed this because Google's uber-extension has a long load time and I wasn't sure where the problem was. Differential Revision: https://phab.mercurial-scm.org/D6381