rust-dirstate: trace append/no append to help debugging

rust: add debug log about skipping dirstate update

test-dirstate: use more robust method to trigger a data-file append The previous method was fragile and somewhat flaky on fast machines.

transaction: tests we don't overwrite bookmark activation on abort We actually do not! Great.

transaction: tests we don't overwrite updates on abort spoiler: we do… /o\

transaction: tests we don't overwrite branch changes on abort We actually do not! Great. …Why are doing a backup of the `branch` files at transaction creation then‽

transaction: tests we don't overwrite tracking to changed file on abort spoiler: we do…

transaction: the base of a new test file checking transaction abort issue See inline documentation for details. See other changesets for actual cases.

setup: support building from an ongoing merge Before this change the two parents from the merge would duplicate some command output and modify some others in a way python 3.11 chokes on.

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.

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).

setup: further improve the error path for version retrieval This is a new take at the problem that 8d390a13474d tried to tackle. There was two issues after that previous improvement: - the 0.0+ version could survive a bit too long and reaching the installer version and staying there. - multiple use case where still failing. So the new code is better at: - always succeeding when running `make local` so that we can bootstrap a local version - no using that fallback outside of `make local` to avoid distribution of version with the buggy version number. The setup.py is a gigantic pile of spaghetti code, to the point where pastafarian pilgrim started knocking at its core. However I refrained from cleaning that up since the more to a `setup.cfg` means this code should be deleted soon™.

dirstate: handle missing backup file on restoration This is the stable counter part to e358f6e0e50e. Since 6.4 will stop writing undo.dirstate in some case (actually… at all), a transaction created with 6.4 and recover/rolledback with 6.3 need to work to a certain degreee. This changeset add the necessary bits so that we don't get a traceback from 6..3 in this cases.

tag: disallow tagging the working directory It's kinda silly, but a clear error message is better than a stacktrace about subscripting `None` when trying to generate the default commit message. I'm surprised that `.revsingle(..).node()` returns None instead of `nodemod.wdirid`, but now there's a test to catch if this changes.