rust: change minimum supported version everywhere applicable

This will help users and downstream packaging.

contrib/nix/flake.nix

@@ -1,177 +1,177 b''
 # flake.nix - Nix-defined package and devel env for the Mercurial project.
 #
 # Copyright 2021-2023 Pacien TRAN-GIRARD <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 # Usage summary, from the root of this repository:
 #
 # Enter a shell with development tools:
 #   nix develop 'hg+file:.?dir=contrib/nix'
 #
 # Running mercurial:
 #   nix run 'hg+file:.?dir=contrib/nix' -- version
 #
 # Running the test suite in a sandbox:
 #   nix build 'hg+file:.?dir=contrib/nix#mercurial-tests' -L
 
 {
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-22.11";
     nixpkgs-black.url = "github:NixOS/nixpkgs/c7cb72b0";  # black 20.8b1
     # rust-overlay.url = "github:oxalica/rust-overlay";
     flake-utils.url = "github:numtide/flake-utils";
     flaky-utils.url = "git+https://cgit.pacien.net/libs/flaky-utils";
   };
 
   outputs = {
     self
   , nixpkgs
   , nixpkgs-black
   # , rust-overlay
   , flake-utils
   , flaky-utils
   }:
   flake-utils.lib.eachDefaultSystem (system:
   let
     # overlays = [ (import rust-overlay) ];
     pkgs = import nixpkgs { inherit system; };
 
     # We're in the contrib/nix sub-directory.
     src = ../..;
 
     # For snapshots, to satisfy extension minimum version requirements.
     dummyVersion = "99.99";
 
     pin = {
       # The test suite has issues with the latest/current versions of Python.
       # Use an older recommended version instead, matching the CI.
       python = pkgs.python39;
 
       # The project uses a pinned version (rust/clippy.toml) for compiling,
       # but uses formatter features from nightly.
       # TODO: make cargo use the formatter from nightly automatically
       #       (not supported by rustup/cargo yet? workaround?)
-      # rustPlatform = pkgs.rust-bin.stable."1.61.0".default;
+      # rustPlatform = pkgs.rust-bin.stable."1.79.0".default;
       # rustPlatformFormatter = pkgs.rust-bin.nightly."2023-04-20".default;
 
       # The CI uses an old version of the Black code formatter,
       # itself depending on old Python libraries.
       # The formatting rules have changed in more recent versions.
       inherit (import nixpkgs-black { inherit system; }) black;
     };
 
   in rec {
     apps.mercurial = apps.mercurial-rust;
     apps.default = apps.mercurial;
     apps.mercurial-c = flake-utils.lib.mkApp {
       drv = packages.mercurial-c;
     };
     apps.mercurial-rust = flake-utils.lib.mkApp {
       drv = packages.mercurial-rust;
     };
 
     packages.mercurial = packages.mercurial-rust;
     packages.default = packages.mercurial;
 
     packages.mercurial-c = pin.python.pkgs.buildPythonApplication {
       format = "other";
       pname = "mercurial";
       version = "SNAPSHOT";
       passthru.exePath = "/bin/hg";
       inherit src;
 
       postPatch = ''
         echo 'version = b"${toString dummyVersion}"' \
           > mercurial/__version__.py
 
         patchShebangs .
 
         for f in **/*.{py,c,t}; do
           # not only used in shebangs
           substituteAllInPlace "$f" '/bin/sh' '${pkgs.stdenv.shell}'
         done
       '';
 
       buildInputs = with pin.python.pkgs; [
         docutils
       ];
 
       nativeBuildInputs = with pkgs; [
         gettext
         installShellFiles
       ];
 
       makeFlags = [
         "PREFIX=$(out)"
       ];
 
       buildPhase = ''
         make local
       '';
 
       # Test suite is huge ; run on-demand in a separate package instead.
       doCheck = false;
     };
 
     packages.mercurial-rust = packages.mercurial-c.overrideAttrs (super: {
       cargoRoot = "rust";
       cargoDeps = pkgs.rustPlatform.importCargoLock {
         lockFile = "${src}/rust/Cargo.lock";
       };
 
       nativeBuildInputs = (super.nativeBuildInputs or []) ++ (
         with pkgs.rustPlatform; [
           cargoSetupHook
           rust.cargo
           rust.rustc
         ]
       );
 
       makeFlags = (super.makeFlags or []) ++ [
         "PURE=--rust"
       ];
     });
 
     packages.mercurial-tests = pkgs.stdenv.mkDerivation {
       pname = "mercurial-tests";
       version = "SNAPSHOT";
       inherit src;
 
       buildInputs = with pkgs; [
         pin.python
         pin.black
         unzip
         which
         sqlite
       ];
 
       postPatch = (packages.mercurial.postPatch or "") + ''
         # * paths emitted by our wrapped hg look like ..hg-wrapped-wrapped
         # * 'hg' is a wrapper; don't run using python directly
         for f in **/*.t; do
           substituteInPlace 2>/dev/null "$f" \
             --replace '*/hg:' '*/*hg*:' \
             --replace '"$PYTHON" "$BINDIR"/hg' '"$BINDIR"/hg'
         done
       '';
 
       buildPhase = ''
         export HGTEST_REAL_HG="${packages.mercurial}/bin/hg"
         export HGMODULEPOLICY="rust+c"
         export HGTESTFLAGS="--blacklist blacklists/nix"
         make check 2>&1 | tee "$out"
       '';
     };
 
     devShell = flaky-utils.lib.mkDevShell {
       inherit pkgs;
 
       tools = [
         pin.python
         pin.black
       ];
     };
   });
 }

rust/README.rst

@@ -1,162 +1,162 b''
 ===================
 Mercurial Rust Code
 ===================
 
 This directory contains various Rust code for the Mercurial project.
 Rust is not required to use (or build) Mercurial, but using it
 improves performance in some areas.
 
 There are currently four independent Rust projects:
 
 - chg. An implementation of chg, in Rust instead of C.
 - hgcli. A project that provides a (mostly) self-contained "hg" binary,
   for ease of deployment and a bit of speed, using PyOxidizer. See
   ``hgcli/README.md``.
 - hg-core (and hg-cpython): implementation of some
   functionality of mercurial in Rust, e.g. ancestry computations in
   revision graphs, status or pull discovery. The top-level ``Cargo.toml`` file
   defines a workspace containing these crates.
 - rhg: a pure Rust implementation of Mercurial, with a fallback mechanism for
   unsupported invocations. It reuses the logic ``hg-core`` but
   completely forgoes interaction with Python. See
   ``rust/rhg/README.md`` for more details.
 
 Using Rust code
 ===============
 
 Local use (you need to clean previous build artifacts if you have
 built without rust previously)::
 
   $ make PURE=--rust local # to use ./hg
   $ ./tests/run-tests.py --rust # to run all tests
   $ ./hg debuginstall | grep -i rust # to validate rust is in use
   checking Rust extensions (installed)
   checking module policy (rust+c-allow)
 
 If the environment variable ``HGWITHRUSTEXT=cpython`` is set, the Rust
 extension will be used by default unless ``--no-rust``.
 
 One day we may use this environment variable to switch to new experimental
 binding crates like a hypothetical ``HGWITHRUSTEXT=hpy``.
 
 Special features
 ================
 
 In the future, compile-time opt-ins may be added
 to the ``features`` section in ``hg-cpython/Cargo.toml``.
 
 To use features from the Makefile, use the ``HG_RUST_FEATURES`` environment
 variable: for instance ``HG_RUST_FEATURES="some-feature other-feature"``.
 
 Profiling
 =========
 
 Setting the environment variable ``RUST_LOG=trace`` will make hg print
 a few high level rust-related performance numbers. It can also
 indicate why the rust code cannot be used (say, using lookarounds in
 hgignore).
 
 Creating a ``.cargo/config`` file with the following content enables
 debug information in optimized builds. This make profiles more informative
 with source file name and line number for Rust stack frames and
 (in some cases) stack frames for Rust functions that have been inlined::
 
   [profile.release]
   debug = true
 
 ``py-spy`` (https://github.com/benfred/py-spy) can be used to
 construct a single profile with rust functions and python functions
 (as opposed to ``hg --profile``, which attributes time spent in rust
 to some unlucky python code running shortly after the rust code, and
 as opposed to tools for native code like ``perf``, which attribute
 time to the python interpreter instead of python functions).
 
 Example usage::
 
   $ make PURE=--rust local # Don't forget to recompile after a code change
   $ py-spy record --native --output /tmp/profile.svg -- ./hg ...
 
 Developing Rust
 ===============
 
 Minimum Supported Rust Version
 ------------------------------
 
 The minimum supported rust version (MSRV) is specified in the `Clippy`_
-configuration file at ``rust/clippy.toml``. It is set to be ``1.61.0`` as of
+configuration file at ``rust/clippy.toml``. It is set to be ``1.79.0`` as of
 this writing, but keep in mind that the authoritative value is the one
 from the configuration file.
 
 We bump it from time to time, with the general rule being that our
 MSRV should not be greater that the version of the Rust toolchain
 shipping with Debian testing, so that the Rust enhanced Mercurial can
 be eventually packaged in Debian.
 
 To ensure that you are not depending on features introduced in later
 versions, you can issue ``rustup override set x.y.z`` at the root of
 the repository.
 
 Build and development
 ---------------------
 
 Go to the ``hg-cpython`` folder::
 
   $ cd rust/hg-cpython
 
 Or, only the ``hg-core`` folder. Be careful not to break compatibility::
 
   $ cd rust/hg-core
 
 Simply run::
 
    $ cargo build --release
 
 It is possible to build without ``--release``, but it is not
 recommended if performance is of any interest: there can be an order
 of magnitude of degradation when removing ``--release``.
 
 For faster builds, you may want to skip code generation::
 
   $ cargo check
 
 For even faster typing::
 
   $ cargo c
 
 You can run only the rust-specific tests (as opposed to tests of
 mercurial as a whole) with::
 
   $ cargo test --all
 
 Formatting the code
 -------------------
 
 We use ``rustfmt`` to keep the code formatted at all times. For now, we are
 using the nightly version because it has been stable enough and provides
 comment folding.
 
 Our CI enforces that the code does not need reformatting. Before
 submitting your changes, please format the entire Rust workspace by running::
 
 
   $ cargo +nightly fmt
 
 This requires you to have the nightly toolchain installed.
 
 Linting: code sanity
 --------------------
 
 We're using `Clippy`_, the standard code diagnosis tool of the Rust
 community.
 
 Our CI enforces that the code is free of Clippy warnings, so you might
 want to run it on your side before submitting your changes. Simply do::
 
   % cargo clippy
 
 from the top of the Rust workspace. Clippy is part of the default
 ``rustup`` install, so it should work right away. In case it would
 not, you can install it with ``rustup component add``.
 
 
 .. _Clippy: https://doc.rust-lang.org/stable/clippy/

rust/clippy.toml

@@ -1,1 +1,1 b''
-msrv = "1.61.0"
+msrv = "1.79.0"