Mercurial > hg
view mercurial/fancyopts.py @ 29375:fcaf20175b1b
demandimport: delay loading for "from a import b" with absolute_import
Before this patch, "from a import b" doesn't delay loading module "b",
if absolute_import is enabled, even though "from . import b" does.
For example:
- it is assumed that extension X has "from P import M" for module M
under package P with absolute_import feature
- if importing module M is already delayed before loading extension
X, loading module M in extension X is delayed until actually
referring
util, cmdutil, scmutil or so of Mercurial itself should be
imported by "from . import M" style before loading extension X
- otherwise, module M is loaded immediately at loading extension X,
even if extension X itself isn't used at that "hg" command invocation
Some minor modules (e.g. filemerge or so) of Mercurial itself
aren't imported by "from . import M" style before loading
extension X. And of course, external libraries aren't, too.
This might cause startup performance problem of hg command, because
many bundled extensions already enable absolute_import feature.
To delay loading module for "from a import b" with absolute_import
feature, this patch does below in "from a (or .a) import b" with
absolute_import case:
1. import root module of "name" by system built-in __import__
(referred as _origimport)
2. recurse down the module chain for hierarchical "name"
This logic can be shared with non absolute_import
case. Therefore, this patch also centralizes it into chainmodules().
3. and fall through to process elements in "fromlist" for the leaf
module of "name"
Processing elements in "fromlist" is executed in the code path
after "if _pypy: .... else: ..." clause. Therefore, this patch
replaces "if _pypy:" with "elif _pypy:" to share it.
At 4f1144c3c72b introducing original "work around" for "from a import
b" case, elements in "fromlist" were imported with "level=level". But
"level" might be grater than 1 (e.g. level=2 in "from .. import b"
case) at demandimport() invocation, and importing direct sub-module in
"fromlist" with level grater than 1 causes unexpected result.
IMHO, this seems main reason of "errors for unknown reason" described
in 4f1144c3c72b, and we don't have to worry about it, because this
issue was already fixed by 78d05778907b.
This is reason why this patch removes "errors for unknown reasons"
comment.
author | FUJIWARA Katsunori <foozy@lares.dti.ne.jp> |
---|---|
date | Sun, 19 Jun 2016 02:17:33 +0900 |
parents | 56b2bcea2529 |
children | e1f0ec0b7d2d |
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# fancyopts.py - better command line parsing # # Copyright 2005-2009 Matt Mackall <mpm@selenic.com> and others # # 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 getopt from .i18n import _ from . import error def gnugetopt(args, options, longoptions): """Parse options mostly like getopt.gnu_getopt. This is different from getopt.gnu_getopt in that an argument of - will become an argument of - instead of vanishing completely. """ extraargs = [] if '--' in args: stopindex = args.index('--') extraargs = args[stopindex + 1:] args = args[:stopindex] opts, parseargs = getopt.getopt(args, options, longoptions) args = [] while parseargs: arg = parseargs.pop(0) if arg and arg[0] == '-' and len(arg) > 1: parseargs.insert(0, arg) topts, newparseargs = getopt.getopt(parseargs, options, longoptions) opts = opts + topts parseargs = newparseargs else: args.append(arg) args.extend(extraargs) return opts, args def fancyopts(args, options, state, gnu=False): """ read args, parse options, and store options in state each option is a tuple of: short option or '' long option default value description option value label(optional) option types include: boolean or none - option sets variable in state to true string - parameter string is stored in state list - parameter string is added to a list integer - parameter strings is stored as int function - call function with parameter non-option args are returned """ namelist = [] shortlist = '' argmap = {} defmap = {} for option in options: if len(option) == 5: short, name, default, comment, dummy = option else: short, name, default, comment = option # convert opts to getopt format oname = name name = name.replace('-', '_') argmap['-' + short] = argmap['--' + oname] = name defmap[name] = default # copy defaults to state if isinstance(default, list): state[name] = default[:] elif callable(default): state[name] = None else: state[name] = default # does it take a parameter? if not (default is None or default is True or default is False): if short: short += ':' if oname: oname += '=' if short: shortlist += short if name: namelist.append(oname) # parse arguments if gnu: parse = gnugetopt else: parse = getopt.getopt opts, args = parse(args, shortlist, namelist) # transfer result to state for opt, val in opts: name = argmap[opt] obj = defmap[name] t = type(obj) if callable(obj): state[name] = defmap[name](val) elif t is type(1): try: state[name] = int(val) except ValueError: raise error.Abort(_('invalid value %r for option %s, ' 'expected int') % (val, opt)) elif t is type(''): state[name] = val elif t is type([]): state[name].append(val) elif t is type(None) or t is type(False): state[name] = True # return unparsed args return args