view tests/test-diff-color.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

Setup

  $ cat <<EOF >> $HGRCPATH
  > [ui]
  > color = yes
  > formatted = always
  > paginate = never
  > [color]
  > mode = ansi
  > EOF
  $ hg init repo
  $ cd repo
  $ cat > a <<EOF
  > c
  > c
  > a
  > a
  > b
  > a
  > a
  > c
  > c
  > EOF
  $ hg ci -Am adda
  adding a
  $ cat > a <<EOF
  > c
  > c
  > a
  > a
  > dd
  > a
  > a
  > c
  > c
  > EOF

default context

  $ hg diff --nodates
  \x1b[0;1mdiff -r cf9f4ba66af2 a\x1b[0m (esc)
  \x1b[0;31;1m--- a/a\x1b[0m (esc)
  \x1b[0;32;1m+++ b/a\x1b[0m (esc)
  \x1b[0;35m@@ -2,7 +2,7 @@\x1b[0m (esc)
   c
   a
   a
  \x1b[0;31m-b\x1b[0m (esc)
  \x1b[0;32m+dd\x1b[0m (esc)
   a
   a
   c

(check that 'ui.color=yes' match '--color=auto')

  $ hg diff --nodates --config ui.formatted=no
  diff -r cf9f4ba66af2 a
  --- a/a
  +++ b/a
  @@ -2,7 +2,7 @@
   c
   a
   a
  -b
  +dd
   a
   a
   c

(check that 'ui.color=no' disable color)

  $ hg diff --nodates --config ui.formatted=yes --config ui.color=no
  diff -r cf9f4ba66af2 a
  --- a/a
  +++ b/a
  @@ -2,7 +2,7 @@
   c
   a
   a
  -b
  +dd
   a
   a
   c

(check that 'ui.color=always' force color)

  $ hg diff --nodates --config ui.formatted=no --config ui.color=always
  \x1b[0;1mdiff -r cf9f4ba66af2 a\x1b[0m (esc)
  \x1b[0;31;1m--- a/a\x1b[0m (esc)
  \x1b[0;32;1m+++ b/a\x1b[0m (esc)
  \x1b[0;35m@@ -2,7 +2,7 @@\x1b[0m (esc)
   c
   a
   a
  \x1b[0;31m-b\x1b[0m (esc)
  \x1b[0;32m+dd\x1b[0m (esc)
   a
   a
   c

--unified=2

  $ hg diff --nodates -U 2
  \x1b[0;1mdiff -r cf9f4ba66af2 a\x1b[0m (esc)
  \x1b[0;31;1m--- a/a\x1b[0m (esc)
  \x1b[0;32;1m+++ b/a\x1b[0m (esc)
  \x1b[0;35m@@ -3,5 +3,5 @@\x1b[0m (esc)
   a
   a
  \x1b[0;31m-b\x1b[0m (esc)
  \x1b[0;32m+dd\x1b[0m (esc)
   a
   a

diffstat

  $ hg diff --stat
   a |  2 \x1b[0;32m+\x1b[0m\x1b[0;31m-\x1b[0m (esc)
   1 files changed, 1 insertions(+), 1 deletions(-)
  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > record =
  > [ui]
  > interactive = true
  > [diff]
  > git = True
  > EOF

#if execbit

record

  $ chmod +x a
  $ hg record -m moda a <<EOF
  > y
  > y
  > EOF
  \x1b[0;1mdiff --git a/a b/a\x1b[0m (esc)
  \x1b[0;36;1mold mode 100644\x1b[0m (esc)
  \x1b[0;36;1mnew mode 100755\x1b[0m (esc)
  1 hunks, 1 lines changed
  \x1b[0;33mexamine changes to 'a'? [Ynesfdaq?]\x1b[0m y (esc)
  
  \x1b[0;35m@@ -2,7 +2,7 @@ c\x1b[0m (esc)
   c
   a
   a
  \x1b[0;31m-b\x1b[0m (esc)
  \x1b[0;32m+dd\x1b[0m (esc)
   a
   a
   c
  \x1b[0;33mrecord this change to 'a'? [Ynesfdaq?]\x1b[0m y (esc)
  

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH
  $ hg rollback
  repository tip rolled back to revision 0 (undo commit)
  working directory now based on revision 0

qrecord

  $ hg qrecord -m moda patch <<EOF
  > y
  > y
  > EOF
  \x1b[0;1mdiff --git a/a b/a\x1b[0m (esc)
  \x1b[0;36;1mold mode 100644\x1b[0m (esc)
  \x1b[0;36;1mnew mode 100755\x1b[0m (esc)
  1 hunks, 1 lines changed
  \x1b[0;33mexamine changes to 'a'? [Ynesfdaq?]\x1b[0m y (esc)
  
  \x1b[0;35m@@ -2,7 +2,7 @@ c\x1b[0m (esc)
   c
   a
   a
  \x1b[0;31m-b\x1b[0m (esc)
  \x1b[0;32m+dd\x1b[0m (esc)
   a
   a
   c
  \x1b[0;33mrecord this change to 'a'? [Ynesfdaq?]\x1b[0m y (esc)
  

  $ hg qpop -a
  popping patch
  patch queue now empty

#endif

issue3712: test colorization of subrepo diff

  $ hg init sub
  $ echo b > sub/b
  $ hg -R sub commit -Am 'create sub'
  adding b
  $ echo 'sub = sub' > .hgsub
  $ hg add .hgsub
  $ hg commit -m 'add subrepo sub'
  $ echo aa >> a
  $ echo bb >> sub/b

  $ hg diff -S
  \x1b[0;1mdiff --git a/a b/a\x1b[0m (esc)
  \x1b[0;31;1m--- a/a\x1b[0m (esc)
  \x1b[0;32;1m+++ b/a\x1b[0m (esc)
  \x1b[0;35m@@ -7,3 +7,4 @@\x1b[0m (esc)
   a
   c
   c
  \x1b[0;32m+aa\x1b[0m (esc)
  \x1b[0;1mdiff --git a/sub/b b/sub/b\x1b[0m (esc)
  \x1b[0;31;1m--- a/sub/b\x1b[0m (esc)
  \x1b[0;32;1m+++ b/sub/b\x1b[0m (esc)
  \x1b[0;35m@@ -1,1 +1,2 @@\x1b[0m (esc)
   b
  \x1b[0;32m+bb\x1b[0m (esc)

test tabs

  $ cat >> a <<EOF
  > 	one tab
  > 		two tabs
  > end tab	
  > mid	tab
  > 	all		tabs	
  > EOF
  $ hg diff --nodates
  \x1b[0;1mdiff --git a/a b/a\x1b[0m (esc)
  \x1b[0;31;1m--- a/a\x1b[0m (esc)
  \x1b[0;32;1m+++ b/a\x1b[0m (esc)
  \x1b[0;35m@@ -7,3 +7,9 @@\x1b[0m (esc)
   a
   c
   c
  \x1b[0;32m+aa\x1b[0m (esc)
  \x1b[0;32m+\x1b[0m	\x1b[0;32mone tab\x1b[0m (esc)
  \x1b[0;32m+\x1b[0m		\x1b[0;32mtwo tabs\x1b[0m (esc)
  \x1b[0;32m+end tab\x1b[0m\x1b[0;1;41m	\x1b[0m (esc)
  \x1b[0;32m+mid\x1b[0m	\x1b[0;32mtab\x1b[0m (esc)
  \x1b[0;32m+\x1b[0m	\x1b[0;32mall\x1b[0m		\x1b[0;32mtabs\x1b[0m\x1b[0;1;41m	\x1b[0m (esc)
  $ echo "[color]" >> $HGRCPATH
  $ echo "diff.tab = bold magenta" >> $HGRCPATH
  $ hg diff --nodates
  \x1b[0;1mdiff --git a/a b/a\x1b[0m (esc)
  \x1b[0;31;1m--- a/a\x1b[0m (esc)
  \x1b[0;32;1m+++ b/a\x1b[0m (esc)
  \x1b[0;35m@@ -7,3 +7,9 @@\x1b[0m (esc)
   a
   c
   c
  \x1b[0;32m+aa\x1b[0m (esc)
  \x1b[0;32m+\x1b[0m\x1b[0;1;35m	\x1b[0m\x1b[0;32mone tab\x1b[0m (esc)
  \x1b[0;32m+\x1b[0m\x1b[0;1;35m		\x1b[0m\x1b[0;32mtwo tabs\x1b[0m (esc)
  \x1b[0;32m+end tab\x1b[0m\x1b[0;1;41m	\x1b[0m (esc)
  \x1b[0;32m+mid\x1b[0m\x1b[0;1;35m	\x1b[0m\x1b[0;32mtab\x1b[0m (esc)
  \x1b[0;32m+\x1b[0m\x1b[0;1;35m	\x1b[0m\x1b[0;32mall\x1b[0m\x1b[0;1;35m		\x1b[0m\x1b[0;32mtabs\x1b[0m\x1b[0;1;41m	\x1b[0m (esc)

  $ cd ..

test inline color diff

  $ hg init inline
  $ cd inline
  $ cat > file1 << EOF
  > this is the first line
  > this is the second line
  >     third line starts with space
  > + starts with a plus sign
  > 	this one with one tab
  > 		now with full two tabs
  > 	now tabs		everywhere, much fun
  > 
  > this line won't change
  > 
  > two lines are going to
  > be changed into three!
  > 
  > three of those lines will
  > collapse onto one
  > (to see if it works)
  > EOF
  $ hg add file1
  $ hg ci -m 'commit'

  $ cat > file1 << EOF
  > that is the first paragraph
  >     this is the second line
  > third line starts with space
  > - starts with a minus sign
  > 	this one with two tab
  > 			now with full three tabs
  > 	now there are tabs		everywhere, much fun
  > 
  > this line won't change
  > 
  > two lines are going to
  > (entirely magically,
  >  assuming this works)
  > be changed into four!
  > 
  > three of those lines have
  > collapsed onto one
  > EOF
  $ hg diff --config experimental.worddiff=False --color=debug
  [diff.diffline|diff --git a/file1 b/file1]
  [diff.file_a|--- a/file1]
  [diff.file_b|+++ b/file1]
  [diff.hunk|@@ -1,16 +1,17 @@]
  [diff.deleted|-this is the first line]
  [diff.deleted|-this is the second line]
  [diff.deleted|-    third line starts with space]
  [diff.deleted|-+ starts with a plus sign]
  [diff.deleted|-][diff.tab|	][diff.deleted|this one with one tab]
  [diff.deleted|-][diff.tab|		][diff.deleted|now with full two tabs]
  [diff.deleted|-][diff.tab|	][diff.deleted|now tabs][diff.tab|		][diff.deleted|everywhere, much fun]
  [diff.inserted|+that is the first paragraph]
  [diff.inserted|+    this is the second line]
  [diff.inserted|+third line starts with space]
  [diff.inserted|+- starts with a minus sign]
  [diff.inserted|+][diff.tab|	][diff.inserted|this one with two tab]
  [diff.inserted|+][diff.tab|			][diff.inserted|now with full three tabs]
  [diff.inserted|+][diff.tab|	][diff.inserted|now there are tabs][diff.tab|		][diff.inserted|everywhere, much fun]
   
   this line won't change
   
   two lines are going to
  [diff.deleted|-be changed into three!]
  [diff.inserted|+(entirely magically,]
  [diff.inserted|+ assuming this works)]
  [diff.inserted|+be changed into four!]
   
  [diff.deleted|-three of those lines will]
  [diff.deleted|-collapse onto one]
  [diff.deleted|-(to see if it works)]
  [diff.inserted|+three of those lines have]
  [diff.inserted|+collapsed onto one]
  $ hg diff --config experimental.worddiff=True --color=debug
  [diff.diffline|diff --git a/file1 b/file1]
  [diff.file_a|--- a/file1]
  [diff.file_b|+++ b/file1]
  [diff.hunk|@@ -1,16 +1,17 @@]
  [diff.deleted|-this is the ][diff.deleted.highlight|first][diff.deleted| line]
  [diff.deleted|-this is the second line]
  [diff.deleted|-][diff.deleted.highlight|    ][diff.deleted|third line starts with space]
  [diff.deleted|-][diff.deleted.highlight|+][diff.deleted| starts with a ][diff.deleted.highlight|plus][diff.deleted| sign]
  [diff.deleted|-][diff.tab|	][diff.deleted|this one with ][diff.deleted.highlight|one][diff.deleted| tab]
  [diff.deleted|-][diff.tab|		][diff.deleted|now with full ][diff.deleted.highlight|two][diff.deleted| tabs]
  [diff.deleted|-][diff.tab|	][diff.deleted|now tabs][diff.tab|		][diff.deleted|everywhere, much fun]
  [diff.inserted|+that is the first paragraph]
  [diff.inserted|+][diff.inserted.highlight|    ][diff.inserted|this is the ][diff.inserted.highlight|second][diff.inserted| line]
  [diff.inserted|+third line starts with space]
  [diff.inserted|+][diff.inserted.highlight|-][diff.inserted| starts with a ][diff.inserted.highlight|minus][diff.inserted| sign]
  [diff.inserted|+][diff.tab|	][diff.inserted|this one with ][diff.inserted.highlight|two][diff.inserted| tab]
  [diff.inserted|+][diff.tab|			][diff.inserted|now with full ][diff.inserted.highlight|three][diff.inserted| tabs]
  [diff.inserted|+][diff.tab|	][diff.inserted|now][diff.inserted.highlight| there are][diff.inserted| tabs][diff.tab|		][diff.inserted|everywhere, much fun]
   
   this line won't change
   
   two lines are going to
  [diff.deleted|-be changed into ][diff.deleted.highlight|three][diff.deleted|!]
  [diff.inserted|+(entirely magically,]
  [diff.inserted|+ assuming this works)]
  [diff.inserted|+be changed into ][diff.inserted.highlight|four][diff.inserted|!]
   
  [diff.deleted|-three of those lines ][diff.deleted.highlight|will]
  [diff.deleted|-][diff.deleted.highlight|collapse][diff.deleted| onto one]
  [diff.deleted|-(to see if it works)]
  [diff.inserted|+three of those lines ][diff.inserted.highlight|have]
  [diff.inserted|+][diff.inserted.highlight|collapsed][diff.inserted| onto one]

multibyte character shouldn't be broken up in word diff:

  $ $PYTHON <<'EOF'
  > with open("utf8", "wb") as f:
  >     f.write(b"blah \xe3\x82\xa2 blah\n")
  > EOF
  $ hg ci -Am 'add utf8 char' utf8
  $ $PYTHON <<'EOF'
  > with open("utf8", "wb") as f:
  >     f.write(b"blah \xe3\x82\xa4 blah\n")
  > EOF
  $ hg ci -m 'slightly change utf8 char' utf8
  $ hg diff --config experimental.worddiff=True --color=debug -c.
  [diff.diffline|diff --git a/utf8 b/utf8]
  [diff.file_a|--- a/utf8]
  [diff.file_b|+++ b/utf8]
  [diff.hunk|@@ -1,1 +1,1 @@]
  [diff.deleted|-blah ][diff.deleted.highlight|\xe3\x82\xa2][diff.deleted| blah] (esc)
  [diff.inserted|+blah ][diff.inserted.highlight|\xe3\x82\xa4][diff.inserted| blah] (esc)