Mercurial > hg
view mercurial/extensions.py @ 23702:c48924787eaa
filectx.parents: enforce changeid of parent to be in own changectx ancestors
Because of the way filenodes are computed, you can have multiple changesets
"introducing" the same file revision. For example, in the changeset graph
below, changeset 2 and 3 both change a file -to- and -from- the same content.
o 3: content = new
|
| o 2: content = new
|/
o 1: content = old
In such cases, the file revision is create once, when 2 is added, and just reused
for 3. So the file change in '3' (from "old" to "new)" has no linkrev pointing
to it). We'll call this situation "linkrev-shadowing". As the linkrev is used for
optimization purposes when walking a file history, the linkrev-shadowing
results in an unexpected jump to another branch during such a walk.. This leads to
multiple bugs with log, annotate and rename detection.
One element to fix such bugs is to ensure that walking the file history sticks on
the same topology as the changeset's history. For this purpose, we extend the
logic in 'basefilectx.parents' so that it always defines the proper changeset
to associate the parent file revision with. This "proper" changeset has to be an
ancestor of the changeset associated with the child file revision.
This logic is performed in the '_adjustlinkrev' function. This function is
given the starting changeset and all the information regarding the parent file
revision. If the linkrev for the file revision is an ancestor of the starting
changeset, the linkrev is valid and will be used. If it is not, we detected a
topological jump caused by linkrev shadowing, we are going to walk the
ancestors of the starting changeset until we find one setting the file to the
revision we are trying to create.
The performance impact appears acceptable:
- We are walking the changelog once for each filelog traversal (as there should
be no overlap between searches),
- changelog traversal itself is fairly cheap, compared to what is likely going
to be perform on the result on the filelog traversal,
- We only touch the manifest for ancestors touching the file, And such
changesets are likely to be the one introducing the file. (except in
pathological cases involving merge),
- We use manifest diff instead of full manifest unpacking to check manifest
content, so it does not involve applying multiple diffs in most case.
- linkrev shadowing is not the common case.
Tests for fixed issues in log, annotate and rename detection have been
added.
But this changeset does not solve all problems. It fixes -ancestry-
computation, but if the linkrev-shadowed changesets is the starting one, we'll
still get things wrong. We'll have to fix the bootstrapping of such operations
in a later changeset. Also, the usage of `hg log FILE` without --follow still
has issues with linkrev pointing to hidden changesets, because it relies on the
`filelog` revset which implement its own traversal logic that is still to be
fixed.
Thanks goes to:
- Matt Mackall: for nudging me in the right direction
- Julien Cristau and RĂ©mi Cardona: for keep telling me linkrev bug were an
evolution show stopper for 3 years.
- Durham Goode: for finding a new linkrev issue every few weeks
- Mads Kiilerich: for that last rename bug who raise this topic over my
anoyance limit.
author | Pierre-Yves David <pierre-yves.david@fb.com> |
---|---|
date | Tue, 23 Dec 2014 15:30:38 -0800 |
parents | ecdbbb6e5d06 |
children | af73c05e735a |
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# extensions.py - extension handling for mercurial # # Copyright 2005-2007 Matt Mackall <mpm@selenic.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. import imp, os import util, cmdutil, error from i18n import _, gettext _extensions = {} _order = [] _ignore = ['hbisect', 'bookmarks', 'parentrevspec', 'interhg', 'inotify'] def extensions(ui=None): if ui: def enabled(name): for format in ['%s', 'hgext.%s']: conf = ui.config('extensions', format % name) if conf is not None and not conf.startswith('!'): return True else: enabled = lambda name: True for name in _order: module = _extensions[name] if module and enabled(name): yield name, module def find(name): '''return module with given extension name''' mod = None try: mod = _extensions[name] except KeyError: for k, v in _extensions.iteritems(): if k.endswith('.' + name) or k.endswith('/' + name): mod = v break if not mod: raise KeyError(name) return mod def loadpath(path, module_name): module_name = module_name.replace('.', '_') path = util.normpath(util.expandpath(path)) if os.path.isdir(path): # module/__init__.py style d, f = os.path.split(path) fd, fpath, desc = imp.find_module(f, [d]) return imp.load_module(module_name, fd, fpath, desc) else: try: return imp.load_source(module_name, path) except IOError, exc: if not exc.filename: exc.filename = path # python does not fill this raise def load(ui, name, path): if name.startswith('hgext.') or name.startswith('hgext/'): shortname = name[6:] else: shortname = name if shortname in _ignore: return None if shortname in _extensions: return _extensions[shortname] _extensions[shortname] = None if path: # the module will be loaded in sys.modules # choose an unique name so that it doesn't # conflicts with other modules mod = loadpath(path, 'hgext.%s' % name) else: def importh(name): mod = __import__(name) components = name.split('.') for comp in components[1:]: mod = getattr(mod, comp) return mod try: mod = importh("hgext.%s" % name) except ImportError, err: ui.debug('could not import hgext.%s (%s): trying %s\n' % (name, err, name)) mod = importh(name) _extensions[shortname] = mod _order.append(shortname) return mod def loadall(ui): result = ui.configitems("extensions") newindex = len(_order) for (name, path) in result: if path: if path[0] == '!': continue try: load(ui, name, path) except KeyboardInterrupt: raise except Exception, inst: if path: ui.warn(_("*** failed to import extension %s from %s: %s\n") % (name, path, inst)) else: ui.warn(_("*** failed to import extension %s: %s\n") % (name, inst)) if ui.traceback(): return 1 for name in _order[newindex:]: uisetup = getattr(_extensions[name], 'uisetup', None) if uisetup: uisetup(ui) for name in _order[newindex:]: extsetup = getattr(_extensions[name], 'extsetup', None) if extsetup: try: extsetup(ui) except TypeError: if extsetup.func_code.co_argcount != 0: raise extsetup() # old extsetup with no ui argument def wrapcommand(table, command, wrapper): '''Wrap the command named `command' in table Replace command in the command table with wrapper. The wrapped command will be inserted into the command table specified by the table argument. The wrapper will be called like wrapper(orig, *args, **kwargs) where orig is the original (wrapped) function, and *args, **kwargs are the arguments passed to it. ''' assert callable(wrapper) aliases, entry = cmdutil.findcmd(command, table) for alias, e in table.iteritems(): if e is entry: key = alias break origfn = entry[0] def wrap(*args, **kwargs): return util.checksignature(wrapper)( util.checksignature(origfn), *args, **kwargs) wrap.__doc__ = getattr(origfn, '__doc__') wrap.__module__ = getattr(origfn, '__module__') newentry = list(entry) newentry[0] = wrap table[key] = tuple(newentry) return entry def wrapfunction(container, funcname, wrapper): '''Wrap the function named funcname in container Replace the funcname member in the given container with the specified wrapper. The container is typically a module, class, or instance. The wrapper will be called like wrapper(orig, *args, **kwargs) where orig is the original (wrapped) function, and *args, **kwargs are the arguments passed to it. Wrapping methods of the repository object is not recommended since it conflicts with extensions that extend the repository by subclassing. All extensions that need to extend methods of localrepository should use this subclassing trick: namely, reposetup() should look like def reposetup(ui, repo): class myrepo(repo.__class__): def whatever(self, *args, **kwargs): [...extension stuff...] super(myrepo, self).whatever(*args, **kwargs) [...extension stuff...] repo.__class__ = myrepo In general, combining wrapfunction() with subclassing does not work. Since you cannot control what other extensions are loaded by your end users, you should play nicely with others by using the subclass trick. ''' assert callable(wrapper) def wrap(*args, **kwargs): return wrapper(origfn, *args, **kwargs) origfn = getattr(container, funcname) assert callable(origfn) setattr(container, funcname, wrap) return origfn def _disabledpaths(strip_init=False): '''find paths of disabled extensions. returns a dict of {name: path} removes /__init__.py from packages if strip_init is True''' import hgext extpath = os.path.dirname(os.path.abspath(hgext.__file__)) try: # might not be a filesystem path files = os.listdir(extpath) except OSError: return {} exts = {} for e in files: if e.endswith('.py'): name = e.rsplit('.', 1)[0] path = os.path.join(extpath, e) else: name = e path = os.path.join(extpath, e, '__init__.py') if not os.path.exists(path): continue if strip_init: path = os.path.dirname(path) if name in exts or name in _order or name == '__init__': continue exts[name] = path return exts def _moduledoc(file): '''return the top-level python documentation for the given file Loosely inspired by pydoc.source_synopsis(), but rewritten to handle triple quotes and to return the whole text instead of just the synopsis''' result = [] line = file.readline() while line[:1] == '#' or not line.strip(): line = file.readline() if not line: break start = line[:3] if start == '"""' or start == "'''": line = line[3:] while line: if line.rstrip().endswith(start): line = line.split(start)[0] if line: result.append(line) break elif not line: return None # unmatched delimiter result.append(line) line = file.readline() else: return None return ''.join(result) def _disabledhelp(path): '''retrieve help synopsis of a disabled extension (without importing)''' try: file = open(path) except IOError: return else: doc = _moduledoc(file) file.close() if doc: # extracting localized synopsis return gettext(doc).splitlines()[0] else: return _('(no help text available)') def disabled(): '''find disabled extensions from hgext. returns a dict of {name: desc}''' try: from hgext import __index__ return dict((name, gettext(desc)) for name, desc in __index__.docs.iteritems() if name not in _order) except (ImportError, AttributeError): pass paths = _disabledpaths() if not paths: return {} exts = {} for name, path in paths.iteritems(): doc = _disabledhelp(path) if doc: exts[name] = doc return exts def disabledext(name): '''find a specific disabled extension from hgext. returns desc''' try: from hgext import __index__ if name in _order: # enabled return else: return gettext(__index__.docs.get(name)) except (ImportError, AttributeError): pass paths = _disabledpaths() if name in paths: return _disabledhelp(paths[name]) def disabledcmd(ui, cmd, strict=False): '''import disabled extensions until cmd is found. returns (cmdname, extname, module)''' paths = _disabledpaths(strip_init=True) if not paths: raise error.UnknownCommand(cmd) def findcmd(cmd, name, path): 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] return (cmd, name, mod) ext = None # first, search for an extension with the same name as the command path = paths.pop(cmd, None) if path: ext = findcmd(cmd, cmd, path) if not ext: # otherwise, interrogate each extension until there's a match for name, path in paths.iteritems(): ext = findcmd(cmd, name, path) if ext: break if ext and 'DEPRECATED' not in ext.__doc__: return ext raise error.UnknownCommand(cmd) def enabled(shortname=True): '''return a dict of {name: desc} of extensions''' exts = {} for ename, ext in extensions(): doc = (gettext(ext.__doc__) or _('(no help text available)')) if shortname: ename = ename.split('.')[-1] exts[ename] = doc.splitlines()[0].strip() return exts def moduleversion(module): '''return version information from given module as a string''' if (util.safehasattr(module, 'getversion') and callable(module.getversion)): version = module.getversion() elif util.safehasattr(module, '__version__'): version = module.__version__ else: version = '' if isinstance(version, (list, tuple)): version = '.'.join(str(o) for o in version) return version