comparison mercurial/extensions.py @ 38162:bdf344aea0ee

extensions: peek command table of disabled extensions without importing

With chg where demandimport disabled, and if disk cache not warm, it took
more than 5 seconds to get "unknown command" error when you typo a command
name. This is horrible UX.

The new implementation is less accurate than the original one as Python
can do anything at import time and cmdtable may be imported from another
module, but I think it's good enough.

Note that the new implementation has to parse .py files, which is slightly
slower than executing .pyc if demandimport is enabled.

38161:aa10675c5dd6

# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import functools
import imp
import inspect
import os

    paths = _disabledpaths()
    if name in paths:
        return _disabledhelp(paths[name])

def _finddisabledcmd(ui, cmd, name, path, strict):
    try:
        mod = loadpath(path, 'hgext.%s' % name)
    except Exception:
        return
    try:
        aliases, entry = cmdutil.findcmd(cmd,
            getattr(mod, 'cmdtable', {}), strict)
    except (error.AmbiguousCommand, error.UnknownCommand):
        return
    except Exception:
        ui.warn(_('warning: error finding commands in %s\n') % path)
        ui.traceback()
        return
    for c in aliases:
        if c.startswith(cmd):
            cmd = c
            break
    else:
        cmd = aliases[0]
    doc = gettext(pycompat.getdoc(mod))
    return (cmd, name, doc)

def disabledcmd(ui, cmd, strict=False):
    '''import disabled extensions until cmd is found.
    returns (cmdname, extname, doc)'''

    paths = _disabledpaths(strip_init=True)
    if not paths:
        raise error.UnknownCommand(cmd)

    ext = None
    # first, search for an extension with the same name as the command

38162:bdf344aea0ee

# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import ast
import collections
import functools
import imp
import inspect
import os

    paths = _disabledpaths()
    if name in paths:
        return _disabledhelp(paths[name])

def _walkcommand(node):
    """Scan @command() decorators in the tree starting at node"""
    todo = collections.deque([node])
    while todo:
        node = todo.popleft()
        if not isinstance(node, ast.FunctionDef):
            todo.extend(ast.iter_child_nodes(node))
            continue
        for d in node.decorator_list:
            if not isinstance(d, ast.Call):
                continue
            if not isinstance(d.func, ast.Name):
                continue
            if d.func.id != r'command':
                continue
            yield d

def _disabledcmdtable(path):
    """Construct a dummy command table without loading the extension module

    This may raise IOError or SyntaxError.
    """
    with open(path, 'rb') as src:
        root = ast.parse(src.read(), path)
    cmdtable = {}
    for node in _walkcommand(root):
        if not node.args:
            continue
        a = node.args[0]
        if isinstance(a, ast.Str):
            name = pycompat.sysbytes(a.s)
        elif pycompat.ispy3 and isinstance(a, ast.Bytes):
            name = a.s
        else:
            continue
        cmdtable[name] = (None, [], b'')
    return cmdtable

def _finddisabledcmd(ui, cmd, name, path, strict):
    try:
        cmdtable = _disabledcmdtable(path)
    except (IOError, SyntaxError):
        return
    try:
        aliases, entry = cmdutil.findcmd(cmd, cmdtable, strict)
    except (error.AmbiguousCommand, error.UnknownCommand):
        return
    for c in aliases:
        if c.startswith(cmd):
            cmd = c
            break
    else:
        cmd = aliases[0]
    doc = _disabledhelp(path)
    return (cmd, name, doc)

def disabledcmd(ui, cmd, strict=False):
    '''find cmd from disabled extensions without importing.
    returns (cmdname, extname, doc)'''

    paths = _disabledpaths()
    if not paths:
        raise error.UnknownCommand(cmd)

    ext = None
    # first, search for an extension with the same name as the command