help: assigning topic categories Differential Revision: https://phab.mercurial-scm.org/D5068

help: assigning categories to existing commands I'm separating this into its own commit so people can bikeshed over the actual categorization (vs the support for categories). These categories are based on the help implementation we've been using internally at Google, and have had zero complaints. Differential Revision: https://phab.mercurial-scm.org/D5067

help: splitting the topics by category Differential Revision: https://phab.mercurial-scm.org/D5066

help: adding support for command categories Differential Revision: https://phab.mercurial-scm.org/D5065

notify: just use email.errors email.Errors is a proxy object to email.errors on Python 2.

rust-chg: add struct holding information needed to spawn server process The Locator will handle the initialization of the connection. It will spawn server processes as needed.

rust-chg: install logger if $CHGDEBUG is set This is modeled after the example logger and debugmsg() of chg/util.c. https://docs.rs/log/0.4.5/log/#implementing-a-logger

rust-chg: depend on log and tokio_timer I'll start porting the daemon management functions from chg of C, which will be difficult to debug without some logging facility. AFAIK, the log crate is easy-to-use and widely used. tokio_timer provides sleep() helper to be used while spawning a server process.

rust-chg: suppress panic while writing chg error to stderr Otherwise "chg >/dev/full 2>&1" would exit with 101. Spotted by test-basic.t.

logcmdutil: add a helpful assertion to catch mistyped templates early This would have made a defect in test-notify.t much easier to figure out. Differential Revision: https://phab.mercurial-scm.org/D5097

notify: adapt to new location of email module's errors Differential Revision: https://phab.mercurial-scm.org/D5099

notify: add some b prefixes # skip-blame just b prefixes Differential Revision: https://phab.mercurial-scm.org/D5098

py3: fix test-diff-color.t Differential Revision: https://phab.mercurial-scm.org/D5095

py3: fix test-revlog.t The mpatchError has a trailing comma on Python 2 but not on Python 3, so use a glob to handle both Python 2 and Python 3. Differential Revision: https://phab.mercurial-scm.org/D5093

fuzz: try *even harder* to prevent Python from looking up usernames Differential Revision: https://phab.mercurial-scm.org/D5092

wireproto: fix incorrect function name in docstring The docstring for `iwireprotocolcommandcacher` references an `onoutputfinished` method. The actual name of the function is `onfinished`. Differential Revision: https://phab.mercurial-scm.org/D5090

py3: fix test-status.t Differential Revision: https://phab.mercurial-scm.org/D5089

formatter: make debug output prettier "(glob)" won't be needed since pprintgen() can print dict items in stable order.

stringutil: allow to specify initial indent level of pprint() I want to pprint() an inner object, which starts with level=1 indent.

stringutil: make level parameter of pprintgen() 0-origin I think this makes more sense in that the level is incremented where nesting goes one more deep.

formatter: use stringutil.pprint() in debug output to drop b''

rust: exposing in parsers module To build with the Rust code, set the HGWITHRUSTEXT environment variable. At this point, it's possible to instantiate and use a rustlazyancestors object from a Python interpreter. The changes in setup.py are obviously a quick hack, just good enough to test/bench without much refactoring. We'd be happy to improve on that with help from the community. Rust bindings crate gets compiled as a static library, which in turn gets linked within 'parsers.so' With respect to the plans at https://www.mercurial-scm.org/wiki/OxidationPlan this would probably qualify as "roll our own FFI". Also, it doesn't quite meet the target of getting rid of C code, since it brings actually more, yet: - the new C code does nothing else than parsing arguments and calling Rust functions. In particular, there's no complex allocation involved. - subsequent changes could rewrite more of revlog.c, this time resulting in an overall decrease of C code and unsafety.

rust: iterator bindings to C code In this changeset, still made of Rust code only, we expose the Rust iterator for instantiation and consumption from C code. The idea is that both the index and index_get_parents() will be passed from the C extension, hence avoiding a hard link dependency to parsers.so, so that the crate can still be built and tested independently. On the other hand, parsers.so will use the symbols defined in this changeset.

rust: pure Rust lazyancestors iterator This is the first of a patch series aiming to provide an alternative implementation in the Rust programming language of the _lazyancestorsiter from the ancestor module. This iterator has been brought to our attention by the people at Octobus, as a potential good candidate for incremental "oxydation" (rewriting in Rust), because it has shown performance issues lately and it merely deals with ints (revision numbers) obtained by calling the index, whih should be directly callable from Rust code, being itself implemented as a C extension. The idea behind this series is to provide a minimal example of Rust code collaborating with existing C and Python code. To open the way to gradually rewriting more of Mercurial's Python code in Rust, without being forced to pay a large initial cost of rewriting the existing fast core into Rust. This patch does not introduce any bindings to other Mercurial code yet. Instead, it introduces the necessary abstractions to address the problem independently, and unit-test it. Since this is the first use of Rust as a Python module within Mercurial, the hg-core crate gets created within this patch. See its Cargo.toml for more details. Someone with a rustc/cargo installation may chdir into rust/hg-core and run the tests by issuing: cargo test --lib The algorithm is a bit simplified (see details in docstrings), and at its simplest becomes rather trivial, showcasing that Rust has batteries included too: BinaryHeap, the Rust analog of Python's heapq does actually all the work. The implementation can be further optimized and probably be made more idiomatic Rust.