Mercurial > hg
diff 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.
author | Yuya Nishihara <yuya@tcha.org> |
---|---|
date | Thu, 03 May 2018 18:38:02 +0900 |
parents | 9d44c71bd892 |
children | b39958d6b81b |
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--- a/mercurial/extensions.py Thu Apr 26 23:00:19 2018 -0400 +++ b/mercurial/extensions.py Thu May 03 18:38:02 2018 +0900 @@ -7,6 +7,8 @@ from __future__ import absolute_import +import ast +import collections import functools import imp import inspect @@ -655,34 +657,67 @@ 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: - mod = loadpath(path, 'hgext.%s' % name) - except Exception: + cmdtable = _disabledcmdtable(path) + except (IOError, SyntaxError): return try: - aliases, entry = cmdutil.findcmd(cmd, - getattr(mod, 'cmdtable', {}), strict) + aliases, entry = cmdutil.findcmd(cmd, 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)) + doc = _disabledhelp(path) return (cmd, name, doc) def disabledcmd(ui, cmd, strict=False): - '''import disabled extensions until cmd is found. + '''find cmd from disabled extensions without importing. returns (cmdname, extname, doc)''' - paths = _disabledpaths(strip_init=True) + paths = _disabledpaths() if not paths: raise error.UnknownCommand(cmd)