view rust/README.rst @ 43457:92e24a139ecc stable

py3: compare http server's command with a native string

The "command" attribute is an str, so comparing with a bytes would not
work on Python 3. This might solve issues in test-lfs-serve-access.t
that happens sometimes (especially in CI):

    --- /hgwork/src/tests/test-lfs-serve-access.t
    +++ /hgwork/src/tests/test-lfs-serve-access.t.err
    @@ -163,11 +163,13 @@

       $ cat $TESTTMP/access.log $TESTTMP/errors.log
       $LOCALIP - - [$LOGDATE$] "POST /missing/objects/batch HTTP/1.1" 404 - (glob)
    +  $LOCALIP - - [05/Nov/2019 16:32:34] "{"objects": [{"oid": "f03217a32529a28a42d03b1244fe09b6e0f9fd06d7b966d4d50567be2abe6c0e", "size": 20}], "operation": "download"}" HTTPStatus.BAD_REQUEST -
       $LOCALIP - - [$LOGDATE$] "GET /subdir/mount/point?cmd=capabilities HTTP/1.1" 200 - (glob)
       $LOCALIP - - [$LOGDATE$] "GET /subdir/mount/point?cmd=batch HTTP/1.1" 200 - x-hgarg-1:cmds=heads+%3Bknown+nodes%3D x-hgproto-1:0.1 0.2 comp=$USUAL_COMPRESSIONS$ partial-pull (glob)
       $LOCALIP - - [$LOGDATE$] "GET /subdir/mount/point?cmd=getbundle HTTP/1.1" 200 - x-hgarg-1:bookmarks=1&bundlecaps=HG20%2Cbundle2%3DHG20%250Abookmarks%250Achangegroup%253D01%252C02%252C03%250Adigests%253Dmd5%252Csha1%252Csha512%250Aerror%253Dabort%252Cunsupportedcontent%252Cpushraced%252Cpushkey%250Ahgtagsfnodes%250Alistkeys%250Aphases%253Dheads%250Apushkey%250Aremote-changegroup%253Dhttp%252Chttps%250Arev-branch-cache%250Astream%253Dv2&cg=1&common=0000000000000000000000000000000000000000&heads=525251863cad618e55d483555f3d00a2ca99597e&listkeys=bookmarks&phases=1 x-hgproto-1:0.1 0.2 comp=$USUAL_COMPRESSIONS$ partial-pull (glob)
       $LOCALIP - - [$LOGDATE$] "POST /subdir/mount/point/.git/info/lfs/objects/batch HTTP/1.1" 200 - (glob)
       $LOCALIP - - [$LOGDATE$] "GET /subdir/mount/point/.hg/lfs/objects/f03217a32529a28a42d03b1244fe09b6e0f9fd06d7b966d4d50567be2abe6c0e HTTP/1.1" 200 - (glob)
    +  $LOCALIP - - [05/Nov/2019 16:32:34] code 400, message Bad request version ('"download"}')

     Blobs that already exist in the usercache are linked into the repo store, even
     though the client doesn't send the blob.
    @@ -195,6 +197,7 @@
       server2/.hg/store/lfs/objects/f0/3217a32529a28a42d03b1244fe09b6e0f9fd06d7b966d4d50567be2abe6c0e
       $ "$PYTHON" $RUNTESTDIR/killdaemons.py $DAEMON_PIDS
       $ cat $TESTTMP/errors.log
    +  $LOCALIP - - [05/Nov/2019 16:32:34] code 400, message Bad request version ('"download"}')

       $ cat >> $TESTTMP/lfsstoreerror.py <<EOF
       > import errno

(from https://ci.hg.gregoryszorc.com/job-info/hg-committed-ca3dca416f8d5863ca6f5a4a6a6bb835dcd5feeb-debian10-cpython-3.7-0)

===================
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.