rust: better treatment of cargo/rustc errors Differential Revision: https://phab.mercurial-scm.org/D5435

rust-cpython: start cpython crate bindings This changeset introduces the hg-cpython crate, that compiles as a shared library holding a whole Python package (mercurial.rustext), with only the empty 'ancestor' submodule for now. Such bindings will be easier and safer to develop and maintain that those of `hg-direct-ffi`. They don't involve C code, only unsafe Rust that's mostly isolated within the cpython crate. The long-term goal would be to import the provided modules, such as rustext.ancestor with mercurial.policy.importmod, same as we already do with cext modules. Differential Revision: https://phab.mercurial-scm.org/D5434

rust-cpython: exclude hgcli from workspace hgcli uses a specific rust-cpython commit by indygreg, of which a PR has been derived which is not merged nor released yet. But we can't use several versions of the sys-python2.7 crate in a single workspace: it makes for a build error. Since hgcli does not at the time being need anything from hg-core, whereas the upcoming hg-cpython will. So for now we're moving hgcli aside, hoping we could base all of them on the same version of rust-cpython again in the future. Differential Revision: https://phab.mercurial-scm.org/D5433

sparse-revlog: protect C code against delta chain including nullrev For unclear reasons, some repositories include nullrev (-1). Re-computing delta for such repo remove nullrev from all chain, so some older versions have been creating them. This currently raise an IndexError with the new C code doing chain slicing as it expect all item to be positive. Both python and C code for reading delta chain preserve nullrev, and the Python code for chain slicing handle the case fine. So we take the safe route and make the new C code works fine in that case.

sparse-revlog: handle nullrev in index_get_length The more generic index_get method handle nullrev fine, we apply the same logic here.

sparse-revlog: handle nullrev in index_get_start The more generic index_get method handle nullrev fine, we apply the same logic here.

revlog: introduce a constant for nullrev in `revlog.c` The value is important enough to be explicitly tracked.

rust: translation of missingancestors This is as direct as possible a translation of the ancestor.missingancestors Python class in pure Rust. The goal for this changeset is to make it easy to compare with the Python version. We also add to Python tests the cases that helped us develop and debug this implementation. Some possible optimizations are marked along the way as TODO comments Differential Revision: https://phab.mercurial-scm.org/D5416

contrib: provide a small script that draw performance plot We have been using this script to look into the result of various runs of the `hg perfrevlogwrite` command. It seems useful enough to be shared more widely.

delta: filter nullrev out first When picking a potential candidate, we filter them on various criteria. The "different from nullrev" criteria is very fast to compute and we should process it first.

perf: report more of the higher range in perfrevlogwrite Since the delta chain length is limited to 1000 revisions, we get a new snapshot about every 1000 revisions. If we assume that the snapshot will be most of the slowest revision, the current display (99% and max) are not very precise in their area. We now include more information about this space in the default report.

help: present boolean arguments as "--[no-]foo" This should make it much more discoverable (we document it in `hg help flags`, but most users don't think to look there). Note that flags that default to None (and not False) will not get this new presentation. We can change the defaults to False later for flags where it makes sense (probably almost all boolean flags). Differential Revision: https://phab.mercurial-scm.org/D5432

help: show "default: off" for boolean flags that default to off Differential Revision: https://phab.mercurial-scm.org/D5431

help: use "default: on" instead of "default: True" "True" feels like a Python thing and not something that users should see. Differential Revision: https://phab.mercurial-scm.org/D5430

check-commit: disallow capitalization only right after topic It should be okay to write "topic: change 'default: True' to 'default: on'". Differential Revision: https://phab.mercurial-scm.org/D5429

absorb: don't prompt to apply changes when there are none to apply Differential Revision: https://phab.mercurial-scm.org/D5428

py3: add a b'' prefix in tests/test-remotefilelog-pull-noshallow.t This makes the test pass on Python 3. # skip-blame because just b'' prefix. Differential Revision: https://phab.mercurial-scm.org/D5427

error: implement __str__ on RevlogError to fix some output defects on Py3 We open-code encoding.unimethod here to avoid cycles, and do a local import of encoding when someone str()s a RevlogError. It's not my favorite solution, but it gets the job done. Differential Revision: https://phab.mercurial-scm.org/D5426

perf: add two more missing b prefixes for Python 3 # skip-blame just two more b prefixes Differential Revision: https://phab.mercurial-scm.org/D5425

match: fix doctest to use bytes instead of str Fixes doctests on Python 3. Differential Revision: https://phab.mercurial-scm.org/D5423

py3: use pycompat.bytechr() instead of chr() in test-fastannotate-revmap.py This makes the test pass on Python 3. Differential Revision: https://phab.mercurial-scm.org/D5422

py3: add a missing b'' prefix in contrib/perf.py # skip-blame because just b'' prefixes This fixes test-contrib-perf.t on Python 3 which started failing. Differential Revision: https://phab.mercurial-scm.org/D5421

py3: use '%d' for integers instead of '%s' This should fix test-rebase-inmemory.t which started failing on Python 3 after recent changes. Differential Revision: https://phab.mercurial-scm.org/D5420

py3: whitelist another passing test caught by buildbot Differential Revision: https://phab.mercurial-scm.org/D5419

py3: fix bad escapes of sub() replacement pattern in test-template-basic.t Python 3.7 starts complaining about it. We have to double the backslash or '\x5c' to get around.

perfdiscovery: benching findcommonheads() This works between the local repo and any peer given by its path, and should be useful for further work on discovery Differential Revision: https://phab.mercurial-scm.org/D5418

merge with stable

templatefuncs: specialize "no match" value of search() to allow % operation If Python had Maybe or Option, the type of the search() result would be Option<Mapping>, which can be considered as a 0/1 container of a Mapping. So it makes sense that {search(r'no match pattern', x) % "whatever"} is mapped to an empty string.

templatefuncs: add regexp search() function that extracts substring This can be used to extract an issue number from a commit message, for example: {search(r'\(issue([0-9]*)\)', desc) % '{1}'}

rust: changed Graph.parents to return [Revision; 2] This will allow for simple iteration on parent revisions, such as: for parent in graph.parents(rev)?.iter().cloned() This seems to be a zero overhead abstraction once built in release mode. Differential Revision: https://phab.mercurial-scm.org/D5415