streamclone: treat volatile file as "fullfile" The nodemap related file might change (or get deleted) during the stream clone in a way incompatible with the streaming process. So we introduce a new flag for this type of file and integrate it with the existing `revlog_type` field recently added to `store.walk` returns. We use that new flat to dispatch such file to the existing mechanism for "atomic replacement" file for the nodemap docket and datafile. This fix the bugs we have been adding tests for. Strictly speaking, the nodemap datafile is happened only a could maybe be used in a slightly more efficient way, however this is good enough for now. Differential Revision: https://phab.mercurial-scm.org/D10481

nodemap: add a test about nodemap "vacuum" during stream clone When the nodemap "vacuum" it generate a new datafile, with a new unique name and delete the old one. This confuse the stream clone code and create the same kind of crash we were seeing in the previous patch. We build a test case where this happens. The next changeset will contains a fix We can also notice that we are, wrongfully exchanging `undo.*` files that the client will not be able to use. This will be dealt with soon. Differential Revision: https://phab.mercurial-scm.org/D10480

nodemap: add a test about racy commit during stream clone That test show that the resulting client nodemap is different from the server one. This happens because the server one transferred a corrupted node map. The data file match the pre-commit content while the docket has post commit content. As the result the nodemap was detected invalid and recomputed. When running without the rust implementation, the code is also generating a new datafile unconditionally, This mean the older file is no longer there are transfer time, resulting in a crash. We will fix this issue later, but we start with writing tests highlighting the issue. Differential Revision: https://phab.mercurial-scm.org/D10479

streamclone: remove sleep based "synchronisation" in tests Sleep based test synchronisation does not work. Variation in machine performance and load can make the two process miss their windows. Instead we migrate to explicit signaling through the file system as other tests file are using. Differential Revision: https://phab.mercurial-scm.org/D10478

testing: add a `write_file` function The function is kinda trivial, but having a simple function avoid silly mistake. Differential Revision: https://phab.mercurial-scm.org/D10477

testing: add a utility function to wait for file create This is similar to `tests/testlib/wait-on-file`, but for the python code Differential Revision: https://phab.mercurial-scm.org/D10476

streamclone: check the errors log in tests Code can be buggy, in that case having error message tend to help. Differential Revision: https://phab.mercurial-scm.org/D10475

mail: use a context manager when writing to mbox Differential Revision: https://phab.mercurial-scm.org/D10484

errors: remove unnecessary varargs handling from OutOfBandError In my recent D10465, I moved some code over from scmutil into `OutOfBandError.__init__`. The code was written to deal with an arbitrary number of `message` arguments to the constructor. It turns out that we only ever pass 0 or 1. Given that, let's simplify it. Differential Revision: https://phab.mercurial-scm.org/D10483

phab-refresh: use a special comment on the stable branch Phabricator make it hard to spot the branch information. As a result patch intended for stable are consistently queued for default. We add a special command and flashy GIF to try to attract reviewer attention on the fact patch are intended for stable. Differential Revision: https://phab.mercurial-scm.org/D10464

phab-refresh: extract the comment in a variable This make the script more readable and it is about to become more complex. Differential Revision: https://phab.mercurial-scm.org/D10463

tests: make test-archive.t pass on py3.9 (issue6504) Something got stricter at parsing URL query parameters and now the parameters need to be separated by "&"; ";" is no longer allowed. See issue6504 for details. Differential Revision: https://phab.mercurial-scm.org/D10472

errors: raise RemoteError in some places in exchange.py This is part of https://www.mercurial-scm.org/wiki/ErrorCategoriesPlan Differential Revision: https://phab.mercurial-scm.org/D10467

errors: introduce a class for remote errors Having an exception for remote errors makes it much easier to exit with the right detailed exit code. Differential Revision: https://phab.mercurial-scm.org/D10466

errors: make OutOfBandError extend Abort I'm about to create a new `RemoteError` exception and make `OutOfBandError` extend it. This patch prepares for that. Differential Revision: https://phab.mercurial-scm.org/D10465

revlog: replace revlog._io.size with a new revlog.index.entry_size The `revlogio` class is mostly a relic from the past. Once in charge of the full revlog related Input/Output code, that class gradually lost responsibilities to the point where more IO are now done by `revlog.index` objects or revlog objects themself. I would like to ultimately remove the `revlogio` class, to do so I start simple with move the "entry size" information on the index. (The index is already responsible of the binary unpacking, so it knows the size. Differential Revision: https://phab.mercurial-scm.org/D10309

perf-discovery: use `get_unique_pull_path` This performance command now use the new API, unless the benchmarked Mercurial is older. Differential Revision: https://phab.mercurial-scm.org/D10423

help: clarify when `$HG_URL` and `$HG_SOURCE` are added in hooks Differential Revision: https://phab.mercurial-scm.org/D10400

nodemap: deal with data mmap error If the file is too small, the mmapread call would raise a ValueError. We catch that and ignore nodemap content (as we do without mmap). This make the repository slightly slower (until the next write) but usable. Unlike the current crash. Differential Revision: https://phab.mercurial-scm.org/D10458

nodemap: test various corruption scenario for the persistent nodemap Corruption can happens in the wild, either because some of our code is buggy or because repository were shared/transfered in a strange manners. Currently one of the corruption case (not enough data) lead to a crash. We add explicit tests for theses cases. Differential Revision: https://phab.mercurial-scm.org/D10457

cmdutil: fix an uninitialize variable usage in clearunfinished() I happened to notice that PyCharm flagged this while looking for something else. I'm pretty sure it meant to check the current state in the iteration, and not keep reusing the last one in the previous iteration. Differential Revision: https://phab.mercurial-scm.org/D10459

help: document `$HG_NEW_OBSMARKERS` in pretxnclose hook Differential Revision: https://phab.mercurial-scm.org/D10399

help: prepend environment variables used in hooks with "$" Most of them have "$" prefix but some don't, so adding it for consistency. Differential Revision: https://phab.mercurial-scm.org/D10398

revset: drop an outdated comment There is not `ui.expandpath` call there anymore. Differential Revision: https://phab.mercurial-scm.org/D10435

ui: deprecated `ui.expandpath` This function return a single path, something incompatible with the coming change to `[paths]` definition to allow multiple associated urls. Now that all user got migrated, we deprecate the function. Differential Revision: https://phab.mercurial-scm.org/D10432

urlutil: remove usage of `ui.expandpath` in `get_clone_path` We want to deprecate `ui.expandpath` and simplify the code before adding more complexity in the form of `[paths]` entry pointing to multiple url. So we inline the relevant bits. Differential Revision: https://phab.mercurial-scm.org/D10431

urlutil: remove usage of `ui.expandpath` in `get_unique_pull_path` We want to deprecate `ui.expandpath` and simplify the code before adding more complexity in the form of `[paths]` entry pointing to multiple url. So we inline the relevant bits. Differential Revision: https://phab.mercurial-scm.org/D10430

urlutil: remove usage of `ui.expandpath` in `get_pull_paths` We want to deprecate `ui.expandpath` and simplify the code before adding more complexity in the form of `[paths]` entry pointing to multiple url. So we inline the relevant bits. Differential Revision: https://phab.mercurial-scm.org/D10429

debugbackupbundle: use `get_unique_pull_path` This is the last known user of `ui.expandpath` outside of `urlutil`. Hooray. Differential Revision: https://phab.mercurial-scm.org/D10428

debugssl: use `get_unique_pull_path` Let's move this code to the new API. Differential Revision: https://phab.mercurial-scm.org/D10427