mirror of
https://github.com/facebook/sapling.git
synced 2024-10-10 08:47:12 +03:00
2afb6aff3e
As the author of several 3rd party extensions, I frequently see bug reports from users attempting to run my extension with an old version of Mercurial that I no longer support in my extension. Oftentimes, the extension will import just fine. But as soon as we run extsetup(), reposetup(), or get into the guts of a wrapped function, we encounter an exception and abort. Today, Mercurial will print a message about extensions that don't have a "testedwith" declaring explicit compatibility with the current version. The existing mechanism is a good start. But it isn't as robust as I would like. Specifically, Mercurial assumes compatibility by default. This means extension authors must perform compatibility checking in their extsetup() or we wait and see if we encounter an abort at runtime. And, compatibility checking can involve a lot of code and lots of error checking. It's a lot of effort for extension authors. Oftentimes, extension authors know which versions of Mercurial there extension works on and more importantly where it is broken. This patch introduces a magic "minimumhgversion" attribute in extensions. When found, the extension loading mechanism will compare the declared version against the current Mercurial version. If the extension explicitly states we require a newer Mercurial version, a warning is printed and the extension isn't loaded beyond importing the Python module. This causes a graceful failure while alerting the user of the compatibility issue. I would be receptive to the idea of making the failure more fatal. However, care would need to be taken to not criple every hg command. e.g. the user may use `hg config` to fix the hgrc and if we aborted trying to run that, the user would effectively be locked out of `hg`! A potential future improvement to this functionality would be to catch ImportError for the extension/module and parse the source code for "minimumhgversion = 'XXX'" and do similar checking. This way we could give more information about why the extension failed to load.
471 lines
14 KiB
Python
471 lines
14 KiB
Python
# extensions.py - extension handling for mercurial
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#
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# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>
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#
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# This software may be used and distributed according to the terms of the
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# GNU General Public License version 2 or any later version.
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from __future__ import absolute_import
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import imp
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import os
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from .i18n import (
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_,
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gettext,
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)
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from . import (
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cmdutil,
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error,
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util,
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)
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_extensions = {}
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_aftercallbacks = {}
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_order = []
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_builtin = set(['hbisect', 'bookmarks', 'parentrevspec', 'progress', 'interhg',
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'inotify'])
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def extensions(ui=None):
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if ui:
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def enabled(name):
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for format in ['%s', 'hgext.%s']:
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conf = ui.config('extensions', format % name)
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if conf is not None and not conf.startswith('!'):
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return True
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else:
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enabled = lambda name: True
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for name in _order:
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module = _extensions[name]
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if module and enabled(name):
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yield name, module
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def find(name):
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'''return module with given extension name'''
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mod = None
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try:
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mod = _extensions[name]
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except KeyError:
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for k, v in _extensions.iteritems():
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if k.endswith('.' + name) or k.endswith('/' + name):
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mod = v
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break
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if not mod:
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raise KeyError(name)
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return mod
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def loadpath(path, module_name):
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module_name = module_name.replace('.', '_')
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path = util.normpath(util.expandpath(path))
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if os.path.isdir(path):
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# module/__init__.py style
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d, f = os.path.split(path)
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fd, fpath, desc = imp.find_module(f, [d])
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return imp.load_module(module_name, fd, fpath, desc)
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else:
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try:
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return imp.load_source(module_name, path)
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except IOError as exc:
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if not exc.filename:
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exc.filename = path # python does not fill this
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raise
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def load(ui, name, path):
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if name.startswith('hgext.') or name.startswith('hgext/'):
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shortname = name[6:]
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else:
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shortname = name
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if shortname in _builtin:
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return None
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if shortname in _extensions:
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return _extensions[shortname]
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_extensions[shortname] = None
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if path:
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# the module will be loaded in sys.modules
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# choose an unique name so that it doesn't
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# conflicts with other modules
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mod = loadpath(path, 'hgext.%s' % name)
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else:
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def importh(name):
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mod = __import__(name)
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components = name.split('.')
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for comp in components[1:]:
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mod = getattr(mod, comp)
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return mod
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try:
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mod = importh("hgext.%s" % name)
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except ImportError as err:
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ui.debug('could not import hgext.%s (%s): trying %s\n'
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% (name, err, name))
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if ui.debugflag:
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ui.traceback()
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mod = importh(name)
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# Before we do anything with the extension, check against minimum stated
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# compatibility. This gives extension authors a mechanism to have their
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# extensions short circuit when loaded with a known incompatible version
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# of Mercurial.
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minver = getattr(mod, 'minimumhgversion', None)
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if minver and util.versiontuple(minver, 2) > util.versiontuple(n=2):
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ui.warn(_('(third party extension %s requires version %s or newer '
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'of Mercurial; disabling)\n') % (shortname, minver))
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return
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_extensions[shortname] = mod
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_order.append(shortname)
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for fn in _aftercallbacks.get(shortname, []):
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fn(loaded=True)
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return mod
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def loadall(ui):
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result = ui.configitems("extensions")
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newindex = len(_order)
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for (name, path) in result:
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if path:
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if path[0] == '!':
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continue
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try:
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load(ui, name, path)
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except KeyboardInterrupt:
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raise
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except Exception as inst:
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if path:
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ui.warn(_("*** failed to import extension %s from %s: %s\n")
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% (name, path, inst))
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else:
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ui.warn(_("*** failed to import extension %s: %s\n")
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% (name, inst))
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ui.traceback()
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for name in _order[newindex:]:
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uisetup = getattr(_extensions[name], 'uisetup', None)
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if uisetup:
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uisetup(ui)
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for name in _order[newindex:]:
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extsetup = getattr(_extensions[name], 'extsetup', None)
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if extsetup:
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try:
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extsetup(ui)
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except TypeError:
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if extsetup.func_code.co_argcount != 0:
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raise
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extsetup() # old extsetup with no ui argument
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# Call aftercallbacks that were never met.
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for shortname in _aftercallbacks:
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if shortname in _extensions:
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continue
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for fn in _aftercallbacks[shortname]:
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fn(loaded=False)
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# loadall() is called multiple times and lingering _aftercallbacks
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# entries could result in double execution. See issue4646.
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_aftercallbacks.clear()
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def afterloaded(extension, callback):
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'''Run the specified function after a named extension is loaded.
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If the named extension is already loaded, the callback will be called
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immediately.
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If the named extension never loads, the callback will be called after
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all extensions have been loaded.
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The callback receives the named argument ``loaded``, which is a boolean
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indicating whether the dependent extension actually loaded.
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'''
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if extension in _extensions:
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callback(loaded=True)
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else:
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_aftercallbacks.setdefault(extension, []).append(callback)
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def bind(func, *args):
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'''Partial function application
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Returns a new function that is the partial application of args and kwargs
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to func. For example,
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f(1, 2, bar=3) === bind(f, 1)(2, bar=3)'''
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assert callable(func)
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def closure(*a, **kw):
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return func(*(args + a), **kw)
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return closure
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def wrapcommand(table, command, wrapper, synopsis=None, docstring=None):
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'''Wrap the command named `command' in table
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Replace command in the command table with wrapper. The wrapped command will
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be inserted into the command table specified by the table argument.
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The wrapper will be called like
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wrapper(orig, *args, **kwargs)
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where orig is the original (wrapped) function, and *args, **kwargs
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are the arguments passed to it.
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Optionally append to the command synopsis and docstring, used for help.
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For example, if your extension wraps the ``bookmarks`` command to add the
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flags ``--remote`` and ``--all`` you might call this function like so:
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synopsis = ' [-a] [--remote]'
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docstring = """
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The ``remotenames`` extension adds the ``--remote`` and ``--all`` (``-a``)
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flags to the bookmarks command. Either flag will show the remote bookmarks
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known to the repository; ``--remote`` will also suppress the output of the
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local bookmarks.
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"""
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extensions.wrapcommand(commands.table, 'bookmarks', exbookmarks,
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synopsis, docstring)
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'''
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assert callable(wrapper)
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aliases, entry = cmdutil.findcmd(command, table)
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for alias, e in table.iteritems():
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if e is entry:
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key = alias
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break
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origfn = entry[0]
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wrap = bind(util.checksignature(wrapper), util.checksignature(origfn))
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wrap.__module__ = getattr(origfn, '__module__')
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doc = getattr(origfn, '__doc__')
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if docstring is not None:
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doc += docstring
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wrap.__doc__ = doc
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newentry = list(entry)
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newentry[0] = wrap
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if synopsis is not None:
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newentry[2] += synopsis
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table[key] = tuple(newentry)
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return entry
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def wrapfunction(container, funcname, wrapper):
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'''Wrap the function named funcname in container
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Replace the funcname member in the given container with the specified
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wrapper. The container is typically a module, class, or instance.
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The wrapper will be called like
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wrapper(orig, *args, **kwargs)
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where orig is the original (wrapped) function, and *args, **kwargs
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are the arguments passed to it.
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Wrapping methods of the repository object is not recommended since
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it conflicts with extensions that extend the repository by
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subclassing. All extensions that need to extend methods of
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localrepository should use this subclassing trick: namely,
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reposetup() should look like
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def reposetup(ui, repo):
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class myrepo(repo.__class__):
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def whatever(self, *args, **kwargs):
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[...extension stuff...]
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super(myrepo, self).whatever(*args, **kwargs)
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[...extension stuff...]
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repo.__class__ = myrepo
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In general, combining wrapfunction() with subclassing does not
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work. Since you cannot control what other extensions are loaded by
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your end users, you should play nicely with others by using the
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subclass trick.
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'''
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assert callable(wrapper)
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origfn = getattr(container, funcname)
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assert callable(origfn)
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setattr(container, funcname, bind(wrapper, origfn))
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return origfn
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def _disabledpaths(strip_init=False):
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'''find paths of disabled extensions. returns a dict of {name: path}
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removes /__init__.py from packages if strip_init is True'''
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import hgext
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extpath = os.path.dirname(os.path.abspath(hgext.__file__))
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try: # might not be a filesystem path
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files = os.listdir(extpath)
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except OSError:
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return {}
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exts = {}
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for e in files:
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if e.endswith('.py'):
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name = e.rsplit('.', 1)[0]
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path = os.path.join(extpath, e)
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else:
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name = e
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path = os.path.join(extpath, e, '__init__.py')
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if not os.path.exists(path):
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continue
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if strip_init:
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path = os.path.dirname(path)
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if name in exts or name in _order or name == '__init__':
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continue
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exts[name] = path
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return exts
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def _moduledoc(file):
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'''return the top-level python documentation for the given file
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Loosely inspired by pydoc.source_synopsis(), but rewritten to
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handle triple quotes and to return the whole text instead of just
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the synopsis'''
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result = []
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line = file.readline()
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while line[:1] == '#' or not line.strip():
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line = file.readline()
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if not line:
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break
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start = line[:3]
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if start == '"""' or start == "'''":
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line = line[3:]
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while line:
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if line.rstrip().endswith(start):
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line = line.split(start)[0]
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if line:
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result.append(line)
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break
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elif not line:
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return None # unmatched delimiter
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result.append(line)
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line = file.readline()
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else:
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return None
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return ''.join(result)
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def _disabledhelp(path):
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'''retrieve help synopsis of a disabled extension (without importing)'''
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try:
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file = open(path)
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except IOError:
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return
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else:
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doc = _moduledoc(file)
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file.close()
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if doc: # extracting localized synopsis
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return gettext(doc).splitlines()[0]
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else:
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return _('(no help text available)')
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def disabled():
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'''find disabled extensions from hgext. returns a dict of {name: desc}'''
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try:
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from hgext import __index__
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return dict((name, gettext(desc))
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for name, desc in __index__.docs.iteritems()
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if name not in _order)
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except (ImportError, AttributeError):
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pass
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paths = _disabledpaths()
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if not paths:
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return {}
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exts = {}
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for name, path in paths.iteritems():
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doc = _disabledhelp(path)
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if doc:
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exts[name] = doc
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return exts
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def disabledext(name):
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'''find a specific disabled extension from hgext. returns desc'''
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try:
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from hgext import __index__
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if name in _order: # enabled
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return
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else:
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return gettext(__index__.docs.get(name))
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except (ImportError, AttributeError):
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pass
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paths = _disabledpaths()
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if name in paths:
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return _disabledhelp(paths[name])
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def disabledcmd(ui, cmd, strict=False):
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'''import disabled extensions until cmd is found.
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returns (cmdname, extname, module)'''
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paths = _disabledpaths(strip_init=True)
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if not paths:
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raise error.UnknownCommand(cmd)
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def findcmd(cmd, name, path):
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try:
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mod = loadpath(path, 'hgext.%s' % name)
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except Exception:
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return
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try:
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aliases, entry = cmdutil.findcmd(cmd,
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getattr(mod, 'cmdtable', {}), strict)
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except (error.AmbiguousCommand, error.UnknownCommand):
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return
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except Exception:
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ui.warn(_('warning: error finding commands in %s\n') % path)
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ui.traceback()
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return
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for c in aliases:
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if c.startswith(cmd):
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cmd = c
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break
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else:
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cmd = aliases[0]
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return (cmd, name, mod)
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ext = None
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# first, search for an extension with the same name as the command
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path = paths.pop(cmd, None)
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if path:
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ext = findcmd(cmd, cmd, path)
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if not ext:
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# otherwise, interrogate each extension until there's a match
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for name, path in paths.iteritems():
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ext = findcmd(cmd, name, path)
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if ext:
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break
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if ext and 'DEPRECATED' not in ext.__doc__:
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return ext
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raise error.UnknownCommand(cmd)
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def enabled(shortname=True):
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'''return a dict of {name: desc} of extensions'''
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exts = {}
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for ename, ext in extensions():
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doc = (gettext(ext.__doc__) or _('(no help text available)'))
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if shortname:
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ename = ename.split('.')[-1]
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exts[ename] = doc.splitlines()[0].strip()
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return exts
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def moduleversion(module):
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'''return version information from given module as a string'''
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if (util.safehasattr(module, 'getversion')
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and callable(module.getversion)):
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version = module.getversion()
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elif util.safehasattr(module, '__version__'):
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version = module.__version__
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else:
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version = ''
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if isinstance(version, (list, tuple)):
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version = '.'.join(str(o) for o in version)
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return version
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