remotenames: work around move of ABCs in collections

This starts warning in Python 3.7, and will break in 3.8. The import
is performed in a curious place because `import collections.abc`
explodes badly on Python 2.7, and `from collections import abc` flunks
our import checker.

Differential Revision: https://phab.mercurial-scm.org/D2847

hgext/remotenames.py

@@ -1,299 +1,305 b''
 # remotenames.py - extension to display remotenames
 #
 # Copyright 2017 Augie Fackler <[e-mail]>
 # Copyright 2017 Sean Farley <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 """ showing remotebookmarks and remotebranches in UI
 
 By default both remotebookmarks and remotebranches are turned on. Config knob to
 control the individually are as follows.
 
 Config options to tweak the default behaviour:
 
 remotenames.bookmarks
   Boolean value to enable or disable showing of remotebookmarks
 
 remotenames.branches
   Boolean value to enable or disable showing of remotebranches
 """
 
 from __future__ import absolute_import
 
-import collections
-
 from mercurial.i18n import _
 
 from mercurial.node import (
     bin,
 )
 from mercurial import (
     logexchange,
     namespaces,
+    pycompat,
     registrar,
     revsetlang,
     smartset,
     templateutil,
 )
 
+if pycompat.ispy3:
+    import collections.abc
+    mutablemapping = collections.abc.MutableMapping
+else:
+    import collections
+    mutablemapping = collections.MutableMapping
+
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'ships-with-hg-core'
 
 configtable = {}
 configitem = registrar.configitem(configtable)
 templatekeyword = registrar.templatekeyword()
 revsetpredicate = registrar.revsetpredicate()
 
 configitem('remotenames', 'bookmarks',
     default=True,
 )
 configitem('remotenames', 'branches',
     default=True,
 )
 
-class lazyremotenamedict(collections.MutableMapping):
+class lazyremotenamedict(mutablemapping):
     """
     Read-only dict-like Class to lazily resolve remotename entries
 
     We are doing that because remotenames startup was slow.
     We lazily read the remotenames file once to figure out the potential entries
     and store them in self.potentialentries. Then when asked to resolve an
     entry, if it is not in self.potentialentries, then it isn't there, if it
     is in self.potentialentries we resolve it and store the result in
     self.cache. We cannot be lazy is when asked all the entries (keys).
     """
     def __init__(self, kind, repo):
         self.cache = {}
         self.potentialentries = {}
         self._kind = kind # bookmarks or branches
         self._repo = repo
         self.loaded = False
 
     def _load(self):
         """ Read the remotenames file, store entries matching selected kind """
         self.loaded = True
         repo = self._repo
         for node, rpath, rname in logexchange.readremotenamefile(repo,
                                                                 self._kind):
             name = rpath + '/' + rname
             self.potentialentries[name] = (node, rpath, name)
 
     def _resolvedata(self, potentialentry):
         """ Check that the node for potentialentry exists and return it """
         if not potentialentry in self.potentialentries:
             return None
         node, remote, name = self.potentialentries[potentialentry]
         repo = self._repo
         binnode = bin(node)
         # if the node doesn't exist, skip it
         try:
             repo.changelog.rev(binnode)
         except LookupError:
             return None
         # Skip closed branches
         if (self._kind == 'branches' and repo[binnode].closesbranch()):
             return None
         return [binnode]
 
     def __getitem__(self, key):
         if not self.loaded:
             self._load()
         val = self._fetchandcache(key)
         if val is not None:
             return val
         else:
             raise KeyError()
 
     def __iter__(self):
         return iter(self.potentialentries)
 
     def __len__(self):
         return len(self.potentialentries)
 
     def __setitem__(self):
         raise NotImplementedError
 
     def __delitem__(self):
         raise NotImplementedError
 
     def _fetchandcache(self, key):
         if key in self.cache:
             return self.cache[key]
         val = self._resolvedata(key)
         if val is not None:
             self.cache[key] = val
             return val
         else:
             return None
 
     def keys(self):
         """ Get a list of bookmark or branch names """
         if not self.loaded:
             self._load()
         return self.potentialentries.keys()
 
     def iteritems(self):
         """ Iterate over (name, node) tuples """
 
         if not self.loaded:
             self._load()
 
         for k, vtup in self.potentialentries.iteritems():
             yield (k, [bin(vtup[0])])
 
 class remotenames(object):
     """
     This class encapsulates all the remotenames state. It also contains
     methods to access that state in convenient ways. Remotenames are lazy
     loaded. Whenever client code needs to ensure the freshest copy of
     remotenames, use the `clearnames` method to force an eventual load.
     """
 
     def __init__(self, repo, *args):
         self._repo = repo
         self.clearnames()
 
     def clearnames(self):
         """ Clear all remote names state """
         self.bookmarks = lazyremotenamedict("bookmarks", self._repo)
         self.branches = lazyremotenamedict("branches", self._repo)
         self._invalidatecache()
 
     def _invalidatecache(self):
         self._nodetobmarks = None
         self._nodetobranch = None
 
     def bmarktonodes(self):
         return self.bookmarks
 
     def nodetobmarks(self):
         if not self._nodetobmarks:
             bmarktonodes = self.bmarktonodes()
             self._nodetobmarks = {}
             for name, node in bmarktonodes.iteritems():
                 self._nodetobmarks.setdefault(node[0], []).append(name)
         return self._nodetobmarks
 
     def branchtonodes(self):
         return self.branches
 
     def nodetobranch(self):
         if not self._nodetobranch:
             branchtonodes = self.branchtonodes()
             self._nodetobranch = {}
             for name, nodes in branchtonodes.iteritems():
                 for node in nodes:
                     self._nodetobranch.setdefault(node, []).append(name)
         return self._nodetobranch
 
 def reposetup(ui, repo):
     if not repo.local():
         return
 
     repo._remotenames = remotenames(repo)
     ns = namespaces.namespace
 
     if ui.configbool('remotenames', 'bookmarks'):
         remotebookmarkns = ns(
             'remotebookmarks',
             templatename='remotebookmarks',
             colorname='remotebookmark',
             logfmt='remote bookmark:  %s\n',
             listnames=lambda repo: repo._remotenames.bmarktonodes().keys(),
             namemap=lambda repo, name:
                 repo._remotenames.bmarktonodes().get(name, []),
             nodemap=lambda repo, node:
                 repo._remotenames.nodetobmarks().get(node, []))
         repo.names.addnamespace(remotebookmarkns)
 
     if ui.configbool('remotenames', 'branches'):
         remotebranchns = ns(
             'remotebranches',
             templatename='remotebranches',
             colorname='remotebranch',
             logfmt='remote branch:  %s\n',
             listnames = lambda repo: repo._remotenames.branchtonodes().keys(),
             namemap = lambda repo, name:
                 repo._remotenames.branchtonodes().get(name, []),
             nodemap = lambda repo, node:
                 repo._remotenames.nodetobranch().get(node, []))
         repo.names.addnamespace(remotebranchns)
 
 @templatekeyword('remotenames', requires={'repo', 'ctx', 'templ'})
 def remotenameskw(context, mapping):
     """List of strings. Remote names associated with the changeset."""
     repo = context.resource(mapping, 'repo')
     ctx = context.resource(mapping, 'ctx')
 
     remotenames = []
     if 'remotebookmarks' in repo.names:
         remotenames = repo.names['remotebookmarks'].names(repo, ctx.node())
 
     if 'remotebranches' in repo.names:
         remotenames += repo.names['remotebranches'].names(repo, ctx.node())
 
     return templateutil.compatlist(context, mapping, 'remotename', remotenames,
                                    plural='remotenames')
 
 @templatekeyword('remotebookmarks', requires={'repo', 'ctx', 'templ'})
 def remotebookmarkskw(context, mapping):
     """List of strings. Remote bookmarks associated with the changeset."""
     repo = context.resource(mapping, 'repo')
     ctx = context.resource(mapping, 'ctx')
 
     remotebmarks = []
     if 'remotebookmarks' in repo.names:
         remotebmarks = repo.names['remotebookmarks'].names(repo, ctx.node())
 
     return templateutil.compatlist(context, mapping, 'remotebookmark',
                                    remotebmarks, plural='remotebookmarks')
 
 @templatekeyword('remotebranches', requires={'repo', 'ctx', 'templ'})
 def remotebrancheskw(context, mapping):
     """List of strings. Remote branches associated with the changeset."""
     repo = context.resource(mapping, 'repo')
     ctx = context.resource(mapping, 'ctx')
 
     remotebranches = []
     if 'remotebranches' in repo.names:
         remotebranches = repo.names['remotebranches'].names(repo, ctx.node())
 
     return templateutil.compatlist(context, mapping, 'remotebranch',
                                    remotebranches, plural='remotebranches')
 
 def _revsetutil(repo, subset, x, rtypes):
     """utility function to return a set of revs based on the rtypes"""
 
     revs = set()
     cl = repo.changelog
     for rtype in rtypes:
         if rtype in repo.names:
             ns = repo.names[rtype]
             for name in ns.listnames(repo):
                 revs.update(ns.nodes(repo, name))
 
     results = (cl.rev(n) for n in revs if cl.hasnode(n))
     return subset & smartset.baseset(sorted(results))
 
 @revsetpredicate('remotenames()')
 def remotenamesrevset(repo, subset, x):
     """All changesets which have a remotename on them."""
     revsetlang.getargs(x, 0, 0, _("remotenames takes no arguments"))
     return _revsetutil(repo, subset, x, ('remotebookmarks', 'remotebranches'))
 
 @revsetpredicate('remotebranches()')
 def remotebranchesrevset(repo, subset, x):
     """All changesets which are branch heads on remotes."""
     revsetlang.getargs(x, 0, 0, _("remotebranches takes no arguments"))
     return _revsetutil(repo, subset, x, ('remotebranches',))
 
 @revsetpredicate('remotebookmarks()')
 def remotebmarksrevset(repo, subset, x):
     """All changesets which have bookmarks on remotes."""
     revsetlang.getargs(x, 0, 0, _("remotebookmarks takes no arguments"))
     return _revsetutil(repo, subset, x, ('remotebookmarks',))