deltas: add a debug-delta-find command to analyse delta search See command documentation for details. For some reason, pytype is confused by our usage of None/deltainfo variable, so I had to quiet it.

deltas: add a `debug.revlog.debug-delta` config option enable output This provide a way to enable the code introduced in the previous changeset. This will provide a large amount of output when applying a bundle with details about each delta "computation".

deltas: add code to display information about the result of `finddeltainfo` I have been looking into performance issue around pull and getting more information about the computation and time involved into applying each revision is very useful. There will be various way to use this new output, so I am introducing the code first.

test: update `test-sparse-revlog` output This got changed at some point.

branching: fix wrong merge conflict resolution from 13dfad0f9f7a 13dfad0f9f7a merged stable into default, but accidentally added the _blockingreader class from stable (but deindented) instead of merging the changes from stable (2fe4efaa59af) into the existing _blockingreader class. This resulted in the _blockingreader being there two times.

debugdeltachain: detect a special case where parents are "skipped" See inline comment for details, this is a case where the delta is neither against p1 or p2, Yet it is still a simple delta part of a simple chain. We now display them as `skip1/skip2` instead of `other`.

debugdeltachain: document the possible value for deltatype So that one can understand what is displayed by the command.

debugdeltachain: also display p1/p2 Looking at the parents is a common need when trying to understanding why a delta was chosen, having it readily available helps a lot.

debugdeltachain: glob variance of "test-generaldelta" We mostly care about generaldelta happening, the exact details of storage size variation is not really important so we can glob it instead of having multiple lines for each variances. This will make updating the output of the command simpler.

debugdeltachain: use the symbolic constant to access entry information This is more robust and easier to read

debugdeltachain: distinct between snapshot and "other" diffs Snapshot are expected to be healthy behavior, while "other" is a bit more suspicious. So we distinct between the two to make it easier to inspect repositories.

branching: merge stable into default

workflow: add a default template for Merge Request Introduce a first basic template to try the feature.

run-tests: prevent race-condition when picking a channel Before this, multiple jobs could search the list at the same time and pick the same free channel. We now project this search/assignment with a simple lock.

run-tests: send the test result after freeing the channel Sending the message about the test being "done" signals to the main thread that a new test can be started. Before this changeset, we sent this signal before freeing the channel, there is room for a race condition where a new test would search for a channel before the old test freed the one it used. This is an example of the failure it would produce: https://foss.heptapod.net/mercurial/mercurial-devel/-/jobs/552404

run-tests: also send a message in the Keyboard interrupt case The next patch will do something equivalent, so lets do the change in an independant changeset first in case we need to bisect something in the future.

revlog: use appropriate format char for int ("i" instead of "I") From https://docs.python.org/3.8/c-api/arg.html#numbers : i (int) [int] Convert a Python integer to a plain C int. I (int) [unsigned int] Convert a Python integer to a C unsigned int, without overflow checking.

revlog: use %d to format int instead of %lu (issue6565) The issue says gcc warns that the data types don't match. I couldn't reproduce the warning locally for some reason, but this patch shouldn't break things. Maybe %lu was simply a copy-paste error from 6b1eae313b2f (https://phab.mercurial-scm.org/D10625).

rhg: correctly handle the case where diffs are encoded relative to nullrev returning a valid entry for nullrev fix chain that delta against nullrev.

test-revlog: test a repository that contains a diff against nullrev We are witnessing a crash in the rust code, so we lets make sure this case is tested.

worker: adapt _blockingreader to work around a python3.8.[0-1] bug (issue6444) Python 3.8.0 is the latest I can load on Ubuntu 18.04, and I regularly hit the TypeError because this function is missing. While it can be avoided by disabling worker usage via config option, that's a bit obscure. I'm limiting the function definition to the narrow range of affected pythons because there were other bugs in this area that were worked around, that I don't fully understand. See the bug report for discussions on why the narrow range, and related commits working around other bugs. Differential Revision: https://phab.mercurial-scm.org/D12627

filelog: show the passed argument on error The error now do more than stating what it need. It also state what it got.

manifest: improve error message in case for tree manifest In the case where tree manifest is not enabled but we still receive an sub directory information for the manifest. The error now inform which sub-directory was passed.

doc: use an absolute path in sys.path The idea and rationale is similar to https://phab.mercurial-scm.org/D12599 (landed as 1b6e381521c5). Differential Revision: https://phab.mercurial-scm.org/D12622

check-py3-compat: use an absolute path in sys.path The idea and rationale is similar to https://phab.mercurial-scm.org/D12599 (landed as 1b6e381521c5). Differential Revision: https://phab.mercurial-scm.org/D12621

branchmap: use a context manager when writing the branchmap This is cleaner and safer. The previous code date from long before we had context manager available.

rhg: align the dirstate v2 writing algorithm with python Use the same algorithm of file append as python does, where we do a manual seek instead of relying on O_APPEND. (see the reasons in the inline comment)

test-dirstate: actually test the append code path in dirstate v2 Apparently it's not sufficient to modify a file to force the dirstate write-out, so the append code path was untested. By removing a file instead of changing we're forcing append to happen.

auto-upgrade: skip the operation if the repository cannot be locked This seems like a fine default behavior for now. If some users wants something more aggressive we can make the behavior configurable in the future. Differential Revision: https://phab.mercurial-scm.org/D12619

auto-upgrade: add a test case where the repository is already locked This show the current behavior when the repository to auto-upgrade is already locked. The current behavior is to abort, which is probably not great. Now that we have a proper test, we can think about the behavior we wants in a later tests. Differential Revision: https://phab.mercurial-scm.org/D12618