view tests/test-hgweb-annotate-whitespace.t @ 46667:93e9f448273c

rhg: Add support for automatic fallback to Python

`rhg` is a command-line application that can do a small subset of what
`hg` can. It is written entirely in Rust, which avoids the cost of starting
a Python interpreter and importing many Python modules.
In a script that runs many `hg` commands, this cost can add up.

However making users decide when to use `rhg` instead of `hg` is
not practical as we want the subset of supported functionality
to grow over time.

Instead we introduce "fallback" behavior where, when `rhg` encounters
something (a sub-command, a repository format, …) that is not implemented
in Rust-only, it does nothing but silently start a subprocess of
Python-based `hg` running the same command.
That way `rhg` becomes a drop-in replacement for `hg` that sometimes
goes faster. Whether Python is used should be an implementation detail
not apparent to users (other than through speed).

A new `fallback` value is added to the previously introduced
`rhg.on-unsupported` configuration key. When in this mode, the new
`rhg.fallback-executable` config is determine what command to use
to run a Python-based `hg`.

The previous `rhg.on-unsupported = abort-silent` configuration was designed
to let a wrapper script call `rhg` and then fall back to `hg` based on the
exit code. This is still available, but having fallback behavior built-in
in rhg might be easier for users instead of leaving that script "as an
exercise for the reader".

Using a subprocess like this is not idea, especially when `rhg` is to be
installed in `$PATH` as `hg`, since the other `hg.py` executable needs
to still be available… somewhere. Eventually this could be replaced
by using PyOxidizer to a have a single executable that embeds a Python
interpreter, but only starts it when needed.

Differential Revision: https://phab.mercurial-scm.org/D10093

#require serve

Create a repo with whitespace only changes

  $ hg init repo-with-whitespace
  $ cd repo-with-whitespace
  $ cat > foo << EOF
  > line 0
  > line 1
  > line 2
  > line 3
  > EOF
  $ hg -q commit -A -m 'commit 0'
  $ cat > foo << EOF
  > line 0
  > line 1 modified by 1
  > line 2
  > line 3
  > EOF
  $ hg commit -m 'commit 1'
  $ cat > foo << EOF
  > line 0
  > line 1 modified by 1
  >     line 2
  > line 3
  > EOF
  $ hg commit -m 'commit 2 (leading whitespace on line 2)'
  $ cat > foo << EOF
  > line 0
  > line 1 modified by 1
  >     line 2
  > EOF
Need to use printf to avoid check-code complaining about trailing whitespace.
  $ printf 'line 3    \n' >> foo
  $ hg commit -m 'commit 3 (trailing whitespace on line 3)'
  $ cat > foo << EOF
  > line  0
  > line 1 modified by 1
  >     line 2
  > EOF
  $ printf 'line 3    \n' >> foo
  $ hg commit -m 'commit 4 (intra whitespace on line 0)'
  $ cat > foo << EOF
  > line  0
  > 
  > line 1 modified by 1
  >     line 2
  > EOF
  $ printf 'line 3    \n' >> foo
  $ hg commit -m 'commit 5 (add blank line between line 0 and 1)'
  $ cat > foo << EOF
  > line  0
  > 
  > 
  > line 1 modified by 1
  >     line 2
  > EOF
  $ printf 'line 3    \n' >> foo
  $ hg commit -m 'commit 6 (add another blank line between line 0 and 1)'

  $ hg log -G -T '{rev}:{node|short} {desc}'
  @  6:9d1b2c7db017 commit 6 (add another blank line between line 0 and 1)
  |
  o  5:400ef1d40470 commit 5 (add blank line between line 0 and 1)
  |
  o  4:08adbe269f24 commit 4 (intra whitespace on line 0)
  |
  o  3:dcb62cfbfc9b commit 3 (trailing whitespace on line 3)
  |
  o  2:6bdb694e7b8c commit 2 (leading whitespace on line 2)
  |
  o  1:23e1e37387dc commit 1
  |
  o  0:b9c578134d72 commit 0
  

  $ hg serve -p $HGPORT -d --pid-file hg.pid
  $ cat hg.pid >> $DAEMON_PIDS
  $ hg serve --config annotate.ignorews=true -p $HGPORT1 -d --pid-file hg.pid
  $ cat hg.pid >> $DAEMON_PIDS
  $ cd ..

Annotate works

  $ get-with-headers.py --json $LOCALIP:$HGPORT 'json-annotate/9d1b2c7db017/foo'
  200 Script output follows
  
  {
    "abspath": "foo",
    "annotate": [
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 4 (intra whitespace on line 0)",
        "line": "line  0\n",
        "lineno": 1,
        "node": "08adbe269f24cf22d975eadeec16790c5b22f558",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 1
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 5 (add blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 2,
        "node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 6 (add another blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 3,
        "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 1",
        "line": "line 1 modified by 1\n",
        "lineno": 4,
        "node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 2 (leading whitespace on line 2)",
        "line": "    line 2\n",
        "lineno": 5,
        "node": "6bdb694e7b8cebb68d5b6b27b4bcc2a49d62c602",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 3 (trailing whitespace on line 3)",
        "line": "line 3    \n",
        "lineno": 6,
        "node": "dcb62cfbfc9b3ab995a5cbbaff6e1971c3e4f865",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 4
      }
    ],
    "author": "test",
    "children": [],
    "date": [
      0.0,
      0
    ],
    "desc": "commit 6 (add another blank line between line 0 and 1)",
    "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
    "parents": [
      "400ef1d404706cfb48afd2b78ce6addf641ced25"
    ],
    "permissions": ""
  }

annotate.ignorews=1 config option is honored

  $ get-with-headers.py --json $LOCALIP:$HGPORT1 'json-annotate/9d1b2c7db017/foo'
  200 Script output follows
  
  {
    "abspath": "foo",
    "annotate": [
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 0",
        "line": "line  0\n",
        "lineno": 1,
        "node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 1
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 5 (add blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 2,
        "node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 6 (add another blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 3,
        "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 1",
        "line": "line 1 modified by 1\n",
        "lineno": 4,
        "node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 0",
        "line": "    line 2\n",
        "lineno": 5,
        "node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 0",
        "line": "line 3    \n",
        "lineno": 6,
        "node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 4
      }
    ],
    "author": "test",
    "children": [],
    "date": [
      0.0,
      0
    ],
    "desc": "commit 6 (add another blank line between line 0 and 1)",
    "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
    "parents": [
      "400ef1d404706cfb48afd2b78ce6addf641ced25"
    ],
    "permissions": ""
  }

ignorews=1 query string argument enables whitespace skipping

  $ get-with-headers.py --json $LOCALIP:$HGPORT 'json-annotate/9d1b2c7db017/foo?ignorews=1'
  200 Script output follows
  
  {
    "abspath": "foo",
    "annotate": [
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 0",
        "line": "line  0\n",
        "lineno": 1,
        "node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 1
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 5 (add blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 2,
        "node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 6 (add another blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 3,
        "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 1",
        "line": "line 1 modified by 1\n",
        "lineno": 4,
        "node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 0",
        "line": "    line 2\n",
        "lineno": 5,
        "node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 0",
        "line": "line 3    \n",
        "lineno": 6,
        "node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 4
      }
    ],
    "author": "test",
    "children": [],
    "date": [
      0.0,
      0
    ],
    "desc": "commit 6 (add another blank line between line 0 and 1)",
    "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
    "parents": [
      "400ef1d404706cfb48afd2b78ce6addf641ced25"
    ],
    "permissions": ""
  }

ignorews=0 query string argument disables when config defaults to enabled

  $ get-with-headers.py --json $LOCALIP:$HGPORT1 'json-annotate/9d1b2c7db017/foo?ignorews=0'
  200 Script output follows
  
  {
    "abspath": "foo",
    "annotate": [
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 4 (intra whitespace on line 0)",
        "line": "line  0\n",
        "lineno": 1,
        "node": "08adbe269f24cf22d975eadeec16790c5b22f558",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 1
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 5 (add blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 2,
        "node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 6 (add another blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 3,
        "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 1",
        "line": "line 1 modified by 1\n",
        "lineno": 4,
        "node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 2 (leading whitespace on line 2)",
        "line": "    line 2\n",
        "lineno": 5,
        "node": "6bdb694e7b8cebb68d5b6b27b4bcc2a49d62c602",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 3 (trailing whitespace on line 3)",
        "line": "line 3    \n",
        "lineno": 6,
        "node": "dcb62cfbfc9b3ab995a5cbbaff6e1971c3e4f865",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 4
      }
    ],
    "author": "test",
    "children": [],
    "date": [
      0.0,
      0
    ],
    "desc": "commit 6 (add another blank line between line 0 and 1)",
    "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
    "parents": [
      "400ef1d404706cfb48afd2b78ce6addf641ced25"
    ],
    "permissions": ""
  }

ignorewsamount=1 query string enables whitespace amount skipping

  $ get-with-headers.py --json $LOCALIP:$HGPORT 'json-annotate/9d1b2c7db017/foo?ignorewsamount=1'
  200 Script output follows
  
  {
    "abspath": "foo",
    "annotate": [
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 0",
        "line": "line  0\n",
        "lineno": 1,
        "node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 1
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 5 (add blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 2,
        "node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 6 (add another blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 3,
        "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 1",
        "line": "line 1 modified by 1\n",
        "lineno": 4,
        "node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 2 (leading whitespace on line 2)",
        "line": "    line 2\n",
        "lineno": 5,
        "node": "6bdb694e7b8cebb68d5b6b27b4bcc2a49d62c602",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 0",
        "line": "line 3    \n",
        "lineno": 6,
        "node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 4
      }
    ],
    "author": "test",
    "children": [],
    "date": [
      0.0,
      0
    ],
    "desc": "commit 6 (add another blank line between line 0 and 1)",
    "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
    "parents": [
      "400ef1d404706cfb48afd2b78ce6addf641ced25"
    ],
    "permissions": ""
  }

ignorewseol=1 query string enables whitespace end of line skipping

  $ get-with-headers.py --json $LOCALIP:$HGPORT 'json-annotate/9d1b2c7db017/foo?ignorewseol=1'
  200 Script output follows
  
  {
    "abspath": "foo",
    "annotate": [
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 4 (intra whitespace on line 0)",
        "line": "line  0\n",
        "lineno": 1,
        "node": "08adbe269f24cf22d975eadeec16790c5b22f558",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 1
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 5 (add blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 2,
        "node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 6 (add another blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 3,
        "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 1",
        "line": "line 1 modified by 1\n",
        "lineno": 4,
        "node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 2 (leading whitespace on line 2)",
        "line": "    line 2\n",
        "lineno": 5,
        "node": "6bdb694e7b8cebb68d5b6b27b4bcc2a49d62c602",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 0",
        "line": "line 3    \n",
        "lineno": 6,
        "node": "b9c578134d72b3a9d26afde8ddd76c0a93c5adbc",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 4
      }
    ],
    "author": "test",
    "children": [],
    "date": [
      0.0,
      0
    ],
    "desc": "commit 6 (add another blank line between line 0 and 1)",
    "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
    "parents": [
      "400ef1d404706cfb48afd2b78ce6addf641ced25"
    ],
    "permissions": ""
  }

ignoreblanklines=1 query string enables whitespace blank line skipping

  $ get-with-headers.py --json $LOCALIP:$HGPORT 'json-annotate/9d1b2c7db017/foo?ignoreblanklines=1'
  200 Script output follows
  
  {
    "abspath": "foo",
    "annotate": [
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 4 (intra whitespace on line 0)",
        "line": "line  0\n",
        "lineno": 1,
        "node": "08adbe269f24cf22d975eadeec16790c5b22f558",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 1
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 5 (add blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 2,
        "node": "400ef1d404706cfb48afd2b78ce6addf641ced25",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 6 (add another blank line between line 0 and 1)",
        "line": "\n",
        "lineno": 3,
        "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 1",
        "line": "line 1 modified by 1\n",
        "lineno": 4,
        "node": "23e1e37387dcfca4c0ed0cc568d1e4b9bfed241a",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 2
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 2 (leading whitespace on line 2)",
        "line": "    line 2\n",
        "lineno": 5,
        "node": "6bdb694e7b8cebb68d5b6b27b4bcc2a49d62c602",
        "revdate": [
          0.0,
          0
        ],
        "targetline": 3
      },
      {
        "abspath": "foo",
        "author": "test",
        "desc": "commit 3 (trailing whitespace on line 3)",
        "line": "line 3    \n",
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        "node": "dcb62cfbfc9b3ab995a5cbbaff6e1971c3e4f865",
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        "targetline": 4
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    "author": "test",
    "children": [],
    "date": [
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    "desc": "commit 6 (add another blank line between line 0 and 1)",
    "node": "9d1b2c7db0175870a950f8c48c9c4ead1058f2c5",
    "parents": [
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    "permissions": ""
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