test: explicit a rebase source in test-rebase-collapse.t At the time of the rebase, the current revision is `null` so this rebase should fail. However, a current bug in formatspec makes it pass, we fix rebase call of the "affected" test to express its actual intent before we fix the actual bug in a later changeset.

tags: join string that's unnecessarily split across lines Differential Revision: https://phab.mercurial-scm.org/D5574

dispatch: add newline after ui.log "ui blocked ms" message Differential Revision: https://phab.mercurial-scm.org/D5573

remotefilelog: fix {file_copies} template keyword remotefilelog overrides templatekw.getrenamedfn(). I changed the return type of that function in ec37df9042f9 (templatekw: make getrenamed() return only filename, not nodeid, 2018-03-26). So we need to change remotefilelog too. The function is used by the {file_copies} template keyword and by `hg log --copies`. Differential Revision: https://phab.mercurial-scm.org/D5576

tests: demonstrate broken {file_copies} template with remotefilelog Differential Revision: https://phab.mercurial-scm.org/D5575

contrib: update window title when possible in perf-revlog-write-plot.py This is useful when comparing multiple graphs.

histedit: add newline after ui.log "# acttions to histedit" message Differential Revision: https://phab.mercurial-scm.org/D5572

rust-cpython: bindings for MissingAncestors The exposition is rather straightforward, except for the remove_ancestors_from() method, which forces us to an inefficient conversion between Python sets and Rust HashSets. Two alternatives are proposed in comments: - changing the inner API to "emit" the revision numbers to discard this would be a substantial change, and it would be better only in the cases where there are more to retain than to discard - mutating the Python set directly: this would force us to define an abstract `RevisionSet` trait, and implement it both for plain `HashSet` and for a struct enclosing a Python set with the GIL marker `Python<'p>`, also a non trivial effort. The main (and seemingly only) caller of this method being `mercurial.setdiscovery`, which is currently undergoing serious refactoring, it's not clear whether these improvements would be worth the effort right now, so we're leaving it as-is. Also, in `get_bases()` (will also be used by `setdiscovery`), we'd prefer to build a Python set directly, but we resort to returning a tuple, waiting to hear back from our PR onto rust-cpython about that Differential Revision: https://phab.mercurial-scm.org/D5550

rust-cpython: generalised conversion function Because `hg::ancestors::MissingAncestors` has methods taking some `HashSet<Revision>` besides `impl IntoIterator<Item = Revision>` as parameters we'll need the more generic `rev_pyiter_collect()` function to also build these Differential Revision: https://phab.mercurial-scm.org/D5549

rust-cpython: style consistency leftovers In particular, during review of `LazyAncestors` bindings, most `match` statements for error conversion have been replaced by higher level methods of `Result` and most personal insecurity comments have been removed. This makes it more systematic. Differential Revision: https://phab.mercurial-scm.org/D5548