dirstate: invalidate on all exceptions Previously, we would miss SystemExit, KeyboardInterrupt etc. This "fix" on the bug tested in "test-largefiles-update.t" by preventing the precisely tested situation to happens at all. However this reveal a similar bug with a different timing. I have not been able to deal with that pre-existing bug so far. So I updated the test to point that out.

large-files: prepare a test for more changes The behavior around this test is about to change. We update the test to make it more robust and the changes clearer.

large-files: larger "changing_parents" context in mergeupdate override This since we are updating the lfdirstate early, it seems reasonable to include the full function in that scope.

large-files: use `hacky_extension_update_file` one more time This override is about merging and can be used in a `changing_parents` context. So lets use the method dedicated to hacky stuff when doing hacky stuff.

typing: disable `signature-mismatch` warnings on a few bytestr functions Recent versions of pytype complain about this, but it seems like expected behavior.

rust: upgrade minimum `rayon` dependency The 1.6.0 and 1.6.1 releases fixes a soundness issue and a performance issue that are both important to us, since both correctness and performance are paramount in the Rust extensions.

branching: merge with stable

test-chg: use a different log to avoid flakyness The test was deleting the log file to start anew. However a trailing working process might still be alive at this time, and recreate the very same log on exit. We see the trace of such worker in the expected content of server.log (see the trace modified by this patch). This is flaky because we don't know *when* the worker will write to the file and there is a race with the `hg init cached` command. A much simpler and reliable way to start anew without having such race is… to write to a different log file. No reuse → no conflict, no conflict → no race, no race → no flakiness.

dirstate-v2: complain early on docket name collision The alternative is that the dirstate gets deleted so the corruption persists and is hard to investigate. This happened to me in tests, where the dirstate names are taken from file, since the file got reverted. I expect this can also happen in prod with non-trivial probability (1/4 billion).

rhg: fix a bug in path_encode This makes rhg able to access long paths at the root of the tree just fine.