view tests/test-convert-mtn.t @ 35569:964212780daf

rust: implementation of `hg`

This commit provides a mostly-working implementation of the
`hg` script in Rust along with scaffolding to support Rust in
the repository.

If you are familiar with Rust, the contents of the added rust/
directory should be pretty straightforward. We create an "hgcli"
package that implements a binary application to run Mercurial.
The output of this package is an "hg" binary.

Our Rust `hg` (henceforth "rhg") essentially is a port of the existing
`hg` Python script. The main difference is the creation of the embedded
CPython interpreter is handled by the binary itself instead of relying
on the shebang. In that sense, rhg is more similar to the "exe wrapper"
we currently use on Windows. However, unlike the exe wrapper, rhg does
not call the `hg` Python script. Instead, it uses the CPython APIs to
import mercurial modules and call appropriate functions. The amount of
code here is surprisingly small.

It is my intent to replace the existing C-based exe wrapper with rhg.
Preferably in the next Mercurial release. This should be achievable -
at least for some Mercurial distributions. The future/timeline for
rhg on other platforms is less clear. We already ship a hg.exe on
Windows. So if we get the quirks with Rust worked out, shipping a
Rust-based hg.exe should hopefully not be too contentious.

Now onto the implementation.

We're using python27-sys and the cpython crates for talking to the
CPython API. We currently don't use too much functionality of the
cpython crate and could have probably cut it out. However, it does
provide a reasonable abstraction over unsafe {} CPython function
calls. While we still have our fair share of those, at least we're
not dealing with too much refcounting, error checking, etc. So I
think the use of the cpython crate is justified. Plus, there is
not-yet-implemented functionality that could benefit from cpython. I
see our use of this crate only increasing.

The cpython and python27-sys crates are not without their issues.
The cpython crate didn't seem to account for the embedding use case
in its design. Instead, it seems to assume that you are building
a Python extension. It is making some questionable decisions around
certain CPython APIs. For example, it insists that
PyEval_ThreadsInitialized() is called and that the Python code
likely isn't the main thread in the underlying application. It
is also missing some functionality that is important for embedded
use cases (such as exporting the path to the Python interpreter
from its build script). After spending several hours trying to
wrangle python27-sys and cpython, I gave up and forked the project
on GitHub. Our Cargo.toml tracks this fork. I'm optimistic that
the upstream project will accept our contributions and we can
eventually unfork.

There is a non-trivial amount of code in our custom Cargo build
script. Our build.rs (which is called as part of building the hgcli
crate):

* Validates that the Python interpreter that was detected by the
  python27-sys crate provides a shared library (we only support
  shared library linking at this time - although this restriction
  could be loosened).
* Validates that the Python is built with UCS-4 support. This ensures
  maximum Unicode compatibility.
* Exports variables to the crate build allowing the built crate to e.g.
  find the path to the Python interpreter.

The produced rhg should be considered alpha quality. There are several
known deficiencies. Many of these are documented with inline TODOs.

Probably the biggest limitation of rhg is that it assumes it is
running from the ./rust/target/<target> directory of a source
distribution. So, rhg is currently not very practical for real-world
use. But, if you can `cargo build` it, running the binary *should*
yield a working Mercurial CLI.

In order to support using rhg with the test harness, we needed to hack
up run-tests.py so the path to Mercurial's Python files is set properly.
The change is extremely hacky and is only intended to be a stop-gap
until the test harness gains first-class support for installing rhg.
This will likely occur after we support running rhg outside the
source directory.

Despite its officially alpha quality, rhg copes extremely well with
the test harness (at least on Linux). Using
`run-tests.py --with-hg ../rust/target/debug/hg`, I only encounter
the following failures:

* test-run-tests.t -- Warnings emitted about using an unexpected
  Mercurial library. This is due to the hacky nature of setting the
  Python directory when run-tests.py detected rhg.
* test-devel-warnings.t -- Expected stack trace missing frame for `hg`
  (This is expected since we no longer have an `hg` script!)
* test-convert.t -- Test running `$PYTHON "$BINDIR"/hg`, which obviously
  assumes `hg` is a Python script.
* test-merge-tools.t -- Same assumption about `hg` being executable with
  Python.
* test-http-bad-server.t -- Seeing exit code 255 instead of 1 around
  line 358.
* test-blackbox.t -- Exit code 255 instead of 1.
* test-basic.t -- Exit code 255 instead of 1.

It certainly looks like we have a bug around exit code handling. I
don't think it is severe enough to hold up review and landing of this
initial implementation. Perfect is the enemy of good.

Differential Revision: https://phab.mercurial-scm.org/D1581

#require mtn

Monotone directory is called .monotone on *nix and monotone
on Windows.

#if windows

  $ mtndir=monotone

#else

  $ mtndir=.monotone

#endif

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "convert=" >> $HGRCPATH

Windows version of monotone home

  $ APPDATA=$HOME; export APPDATA

tedious monotone keys configuration
The /dev/null redirection is necessary under Windows, or
it complains about home directory permissions

  $ mtn --quiet genkey [e-mail] 1>/dev/null 2>&1 <<EOF
  > passphrase
  > passphrase
  > EOF
  $ cat >> $HOME/$mtndir/monotonerc <<EOF
  > function get_passphrase(keypair_id)
  >     return "passphrase"
  > end
  > EOF

create monotone repository

  $ mtn db init --db=repo.mtn
  $ mtn --db=repo.mtn --branch=com.selenic.test setup workingdir
  $ cd workingdir
  $ echo a > a
  $ mkdir dir
  $ echo b > dir/b
  $ echo d > dir/d
  $ $PYTHON -c 'file("bin", "wb").write("a\\x00b")'
  $ echo c > c
  $ mtn add a dir/b dir/d c bin
  mtn: adding 'a' to workspace manifest
  mtn: adding 'bin' to workspace manifest
  mtn: adding 'c' to workspace manifest
  mtn: adding 'dir' to workspace manifest
  mtn: adding 'dir/b' to workspace manifest
  mtn: adding 'dir/d' to workspace manifest
  $ mtn ci -m initialize
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 0f6e5e4f2e7d2a8ef312408f57618abf026afd90

update monotone working directory

  $ mtn mv a dir/a
  mtn: skipping 'dir', already accounted for in workspace
  mtn: renaming 'a' to 'dir/a' in workspace manifest
  $ echo a >> dir/a
  $ echo b >> dir/b
  $ mtn drop c
  mtn: dropping 'c' from workspace manifest
  $ $PYTHON -c 'file("bin", "wb").write("b\\x00c")'
  $ mtn ci -m update1
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 51d0a982464573a2a2cf5ee2c9219c652aaebeff
  $ cd ..

convert once

  $ hg convert -s mtn repo.mtn
  assuming destination repo.mtn-hg
  initializing destination repo.mtn-hg repository
  scanning source...
  sorting...
  converting...
  1 initialize
  0 update1
  $ cd workingdir
  $ echo e > e
  $ mtn add e
  mtn: adding 'e' to workspace manifest
  $ mtn drop dir/b
  mtn: dropping 'dir/b' from workspace manifest
  $ mtn mv bin bin2
  mtn: renaming 'bin' to 'bin2' in workspace manifest
  $ mtn ci -m 'update2 "with" quotes'
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision ebe58335d85d8cb176b6d0a12be04f5314b998da

test directory move

  $ mkdir -p dir1/subdir1
  $ mkdir -p dir1/subdir2_other
  $ echo file1 > dir1/subdir1/file1
  $ echo file2 > dir1/subdir2_other/file1
  $ mtn add dir1/subdir1/file1 dir1/subdir2_other/file1
  mtn: adding 'dir1' to workspace manifest
  mtn: adding 'dir1/subdir1' to workspace manifest
  mtn: adding 'dir1/subdir1/file1' to workspace manifest
  mtn: adding 'dir1/subdir2_other' to workspace manifest
  mtn: adding 'dir1/subdir2_other/file1' to workspace manifest
  $ mtn ci -m createdir1
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision a8d62bc04fee4d2936d28e98bbcc81686dd74306
  $ mtn rename dir1/subdir1 dir1/subdir2
  mtn: skipping 'dir1', already accounted for in workspace
  mtn: renaming 'dir1/subdir1' to 'dir1/subdir2' in workspace manifest
  $ mtn ci -m movedir1
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 2c3d241bbbfe538b1b51d910f5676407e3f4d3a6

test subdirectory move

  $ mtn mv dir dir2
  mtn: renaming 'dir' to 'dir2' in workspace manifest
  $ echo newfile > dir2/newfile
  $ mtn drop dir2/d
  mtn: dropping 'dir2/d' from workspace manifest
  $ mtn add dir2/newfile
  mtn: adding 'dir2/newfile' to workspace manifest
  $ mtn ci -m movedir
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision fdb5a02dae8bfce3a79b3393680af471016e1b4c

Test directory removal with empty directory

  $ mkdir dir2/dir
  $ mkdir dir2/dir/subdir
  $ echo f > dir2/dir/subdir/f
  $ mkdir dir2/dir/emptydir
  $ mtn add --quiet -R dir2/dir
  $ mtn ci -m emptydir
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 8bbf76d717001d24964e4604739fdcd0f539fc88
  $ mtn drop -R dir2/dir
  mtn: dropping 'dir2/dir/subdir/f' from workspace manifest
  mtn: dropping 'dir2/dir/subdir' from workspace manifest
  mtn: dropping 'dir2/dir/emptydir' from workspace manifest
  mtn: dropping 'dir2/dir' from workspace manifest
  $ mtn ci -m dropdirectory
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 2323d4bc324e6c82628dc04d47a9fd32ad24e322

test directory and file move

  $ mkdir -p dir3/d1
  $ echo a > dir3/a
  $ mtn add dir3/a dir3/d1
  mtn: adding 'dir3' to workspace manifest
  mtn: adding 'dir3/a' to workspace manifest
  mtn: adding 'dir3/d1' to workspace manifest
  $ mtn ci -m dirfilemove
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 47b192f720faa622f48c68d1eb075b26d405aa8b
  $ mtn mv dir3/a dir3/d1/a
  mtn: skipping 'dir3/d1', already accounted for in workspace
  mtn: renaming 'dir3/a' to 'dir3/d1/a' in workspace manifest
  $ mtn mv dir3/d1 dir3/d2
  mtn: skipping 'dir3', already accounted for in workspace
  mtn: renaming 'dir3/d1' to 'dir3/d2' in workspace manifest
  $ mtn ci -m dirfilemove2
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 8b543a400d3ee7f6d4bb1835b9b9e3747c8cb632

test directory move into another directory move

  $ mkdir dir4
  $ mkdir dir5
  $ echo a > dir4/a
  $ mtn add dir4/a dir5
  mtn: adding 'dir4' to workspace manifest
  mtn: adding 'dir4/a' to workspace manifest
  mtn: adding 'dir5' to workspace manifest
  $ mtn ci -m dirdirmove
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 466e0b2afc7a55aa2b4ab2f57cb240bb6cd66fc7
  $ mtn mv dir5 dir6
  mtn: renaming 'dir5' to 'dir6' in workspace manifest
  $ mtn mv dir4 dir6/dir4
  mtn: skipping 'dir6', already accounted for in workspace
  mtn: renaming 'dir4' to 'dir6/dir4' in workspace manifest
  $ mtn ci -m dirdirmove2
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 3d1f77ebad0c23a5d14911be3b670f990991b749

test diverging directory moves

  $ mkdir -p dir7/dir9/dir8
  $ echo a > dir7/dir9/dir8/a
  $ echo b > dir7/dir9/b
  $ echo c > dir7/c
  $ mtn add -R dir7
  mtn: adding 'dir7' to workspace manifest
  mtn: adding 'dir7/c' to workspace manifest
  mtn: adding 'dir7/dir9' to workspace manifest
  mtn: adding 'dir7/dir9/b' to workspace manifest
  mtn: adding 'dir7/dir9/dir8' to workspace manifest
  mtn: adding 'dir7/dir9/dir8/a' to workspace manifest
  $ mtn ci -m divergentdirmove
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 08a08511f18b428d840199b062de90d0396bc2ed
  $ mtn mv dir7 dir7-2
  mtn: renaming 'dir7' to 'dir7-2' in workspace manifest
  $ mtn mv dir7-2/dir9 dir9-2
  mtn: renaming 'dir7-2/dir9' to 'dir9-2' in workspace manifest
  $ mtn mv dir9-2/dir8 dir8-2
  mtn: renaming 'dir9-2/dir8' to 'dir8-2' in workspace manifest
  $ mtn ci -m divergentdirmove2
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision 4a736634505795f17786fffdf2c9cbf5b11df6f6

test large file support (> 32kB)

  >>> fp = file('large-file', 'wb')
  >>> for x in xrange(10000): fp.write('%d\n' % x)
  >>> fp.close()
  $ md5sum.py large-file
  5d6de8a95c3b6bf9e0ffb808ba5299c1  large-file
  $ mtn add large-file
  mtn: adding 'large-file' to workspace manifest
  $ mtn ci -m largefile
  mtn: beginning commit on branch 'com.selenic.test'
  mtn: committed revision f0a20fecd10dc4392d18fe69a03f1f4919d3387b

test suspending (closing a branch)

  $ mtn suspend f0a20fecd10dc4392d18fe69a03f1f4919d3387b 2> /dev/null
  $ cd ..

convert incrementally

  $ hg convert -s mtn repo.mtn
  assuming destination repo.mtn-hg
  scanning source...
  sorting...
  converting...
  12 update2 "with" quotes
  11 createdir1
  10 movedir1
  9 movedir
  8 emptydir
  7 dropdirectory
  6 dirfilemove
  5 dirfilemove2
  4 dirdirmove
  3 dirdirmove2
  2 divergentdirmove
  1 divergentdirmove2
  0 largefile
  $ glog()
  > {
  >     hg log -G --template '{rev} "{desc|firstline}" files: {files}\n' "$@"
  > }
  $ cd repo.mtn-hg
  $ hg up -C
  12 files updated, 0 files merged, 0 files removed, 0 files unresolved
  no open descendant heads on branch "com.selenic.test", updating to a closed head
  (committing will reopen branch "com.selenic.test")
  $ glog
  @  14 "largefile" files: large-file
  |
  o  13 "divergentdirmove2" files: dir7-2/c dir7/c dir7/dir9/b dir7/dir9/dir8/a dir8-2/a dir9-2/b
  |
  o  12 "divergentdirmove" files: dir7/c dir7/dir9/b dir7/dir9/dir8/a
  |
  o  11 "dirdirmove2" files: dir4/a dir6/dir4/a
  |
  o  10 "dirdirmove" files: dir4/a
  |
  o  9 "dirfilemove2" files: dir3/a dir3/d2/a
  |
  o  8 "dirfilemove" files: dir3/a
  |
  o  7 "dropdirectory" files: dir2/dir/subdir/f
  |
  o  6 "emptydir" files: dir2/dir/subdir/f
  |
  o  5 "movedir" files: dir/a dir/d dir2/a dir2/newfile
  |
  o  4 "movedir1" files: dir1/subdir1/file1 dir1/subdir2/file1
  |
  o  3 "createdir1" files: dir1/subdir1/file1 dir1/subdir2_other/file1
  |
  o  2 "update2 "with" quotes" files: bin bin2 dir/b e
  |
  o  1 "update1" files: a bin c dir/a dir/b
  |
  o  0 "initialize" files: a bin c dir/b dir/d
  

manifest

  $ hg manifest
  bin2
  dir1/subdir2/file1
  dir1/subdir2_other/file1
  dir2/a
  dir2/newfile
  dir3/d2/a
  dir6/dir4/a
  dir7-2/c
  dir8-2/a
  dir9-2/b
  e
  large-file

contents

  $ cat dir2/a
  a
  a
  $ test -d dir2/dir && echo 'removed dir2/dir is still there!'
  [1]

file move

  $ hg log -v -C -r 1 | grep copies
  copies:      dir/a (a)

check directory move

  $ hg manifest -r 4
  bin2
  dir/a
  dir/d
  dir1/subdir2/file1
  dir1/subdir2_other/file1
  e
  $ test -d dir1/subdir2 || echo 'new dir1/subdir2 does not exist!'
  $ test -d dir1/subdir1 && echo 'renamed dir1/subdir1 is still there!'
  [1]
  $ hg log -v -C -r 4 | grep copies
  copies:      dir1/subdir2/file1 (dir1/subdir1/file1)

check file remove with directory move

  $ hg manifest -r 5
  bin2
  dir1/subdir2/file1
  dir1/subdir2_other/file1
  dir2/a
  dir2/newfile
  e

check file move with directory move

  $ hg manifest -r 9
  bin2
  dir1/subdir2/file1
  dir1/subdir2_other/file1
  dir2/a
  dir2/newfile
  dir3/d2/a
  e

check file directory directory move

  $ hg manifest -r 11
  bin2
  dir1/subdir2/file1
  dir1/subdir2_other/file1
  dir2/a
  dir2/newfile
  dir3/d2/a
  dir6/dir4/a
  e

check divergent directory moves

  $ hg manifest -r 13
  bin2
  dir1/subdir2/file1
  dir1/subdir2_other/file1
  dir2/a
  dir2/newfile
  dir3/d2/a
  dir6/dir4/a
  dir7-2/c
  dir8-2/a
  dir9-2/b
  e

test large file support (> 32kB)

  $ md5sum.py large-file
  5d6de8a95c3b6bf9e0ffb808ba5299c1  large-file

check branch closing

  $ hg branches -a
  $ hg branches -c
  com.selenic.test              14:* (closed) (glob)