Mercurial > hg
view rust/README.rst @ 38737:913ca175c4ae
aggressivemergedelta: document rename and move to `revlog` section
The config does not follow our naming guideline and "Aggressive" is probably a
word to keep away from users.
The option does not truly fit in the `format` section. It can be turned on and
off for existing repository without much consequence regarding compatibility.
A new `revlog` option is created to control behavior related to revlog writing
and reading. We can see multiple other config options that could be migrated
there.
* format.maxchainlen
* experimental.mmapindexthreshold
* experimental.sparse-read.density-threshold (in an updated form)
* experimental.sparse-read.min-gap-size (in an updated form)
In addition, we can foresee at least a couple of sparse-revlog related option
coming too (to reduce delta chain length and increase snapshot reuse)
These two extra options might fit there too. Unless we want to create a
section dedicated to caches and performance.
* format.chunkcachesize
* format.manifestcachesize
For now, we only migrate `optimize-delta-parent-choice` since it is getting
out of experimental. It is too close to the release to move the other one. In
addition, we still lack proper the prioritization of alias that would help
renaming them without bad consequence for users.
(Not fully happy about the `revlog` name but could not find better).
author | Boris Feld <boris.feld@octobus.net> |
---|---|
date | Thu, 19 Jul 2018 10:35:29 +0200 |
parents | 964212780daf |
children | 8a3b045d9086 |
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=================== Mercurial Rust Code =================== This directory contains various Rust code for the Mercurial project. The top-level ``Cargo.toml`` file defines a workspace containing all primary Mercurial crates. Building ======== To build the Rust components:: $ cargo build If you prefer a non-debug / release configuration:: $ cargo build --release Features -------- The following Cargo features are available: localdev (default) Produce files that work with an in-source-tree build. In this mode, the build finds and uses a ``python2.7`` binary from ``PATH``. The ``hg`` binary assumes it runs from ``rust/target/<target>hg`` and it finds Mercurial files at ``dirname($0)/../../../``. Build Mechanism --------------- The produced ``hg`` binary is *bound* to a CPython installation. The binary links against and loads a CPython library that is discovered at build time (by a ``build.rs`` Cargo build script). The Python standard library defined by this CPython installation is also used. Finding the appropriate CPython installation to use is done by the ``python27-sys`` crate's ``build.rs``. Its search order is:: 1. ``PYTHON_SYS_EXECUTABLE`` environment variable. 2. ``python`` executable on ``PATH`` 3. ``python2`` executable on ``PATH`` 4. ``python2.7`` executable on ``PATH`` Additional verification of the found Python will be performed by our ``build.rs`` to ensure it meets Mercurial's requirements. Details about the build-time configured Python are built into the produced ``hg`` binary. This means that a built ``hg`` binary is only suitable for a specific, well-defined role. These roles are controlled by Cargo features (see above). Running ======= The ``hgcli`` crate produces an ``hg`` binary. You can run this binary via ``cargo run``:: $ cargo run --manifest-path hgcli/Cargo.toml Or directly:: $ target/debug/hg $ target/release/hg You can also run the test harness with this binary:: $ ./run-tests.py --with-hg ../rust/target/debug/hg .. note:: Integration with the test harness is still preliminary. Remember to ``cargo build`` after changes because the test harness doesn't yet automatically build Rust code.