Add comments to clarify the purpose of some member variables.

gclient.py

 #!/usr/bin/python
 # Copyright (c) 2010 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Meta checkout manager supporting both Subversion and GIT.
 
 Files
   .gclient      : Current client configuration, written by 'config' command.
                   Format is a Python script defining 'solutions', a list whose
@@ skipping 136 matching lines @@
     # These 2 are only set in .gclient and not in DEPS files.
     self.safesync_url = safesync_url
     self.custom_vars = custom_vars or {}
     self.custom_deps = custom_deps or {}
     self.deps_hooks = []
     self.dependencies = []
     self.deps_file = deps_file or self.DEPS_FILE
     # A cache of the files affected by the current operation, necessary for
     # hooks.
     self.file_list = []
+    # If it is not set to True, the dependency wasn't processed for its child
+    # dependency, i.e. its DEPS wasn't read.
     self.deps_parsed = False
+    # A direct reference is dependency that is referenced by a deps, deps_os or
+    # solution. A indirect one is one that was loaded with From() or that
+    # exceeded recursion limit.
     self.direct_reference = False
 
     # Sanity checks
     if not self.name and self.parent:
       raise gclient_utils.Error('Dependency without name')
     tree = dict((d.name, d) for d in self.tree(False))
     if self.name in tree:
       raise gclient_utils.Error(
           'Dependency %s specified more than once:\n  %s\nvs\n  %s' %
           (self.name, tree[self.name].hierarchy(), self.hierarchy()))
@@ skipping 116 matching lines @@
         # normpath is required to allow DEPS to use .. in their
         # dependency local path.
         rel_deps[os.path.normpath(os.path.join(self.name, d))] = url
       deps = rel_deps
 
     # Convert the deps into real Dependency.
     for name, url in deps.iteritems():
       if name in [s.name for s in self.dependencies]:
         raise
       self.dependencies.append(Dependency(self, name, url))
+    # Note: do not sort by name, the dependencies must be specified in the
+    # logical order.
     logging.info('Loaded: %s' % str(self))
 
   def RunCommandRecursively(self, options, revision_overrides,
                             command, args, pm):
     """Runs 'command' before parsing the DEPS in case it's a initial checkout
     or a revert."""
     assert self.file_list == []
     # When running runhooks, there's no need to consult the SCM.
     # All known hooks are expected to run unconditionally regardless of working
     # copy state, so skip the SCM status check.
@@ skipping 839 matching lines @@
     return CMDhelp(parser, argv)
   except gclient_utils.Error, e:
     print >> sys.stderr, 'Error: %s' % str(e)
     return 1
 
 
 if '__main__' == __name__:
   sys.exit(Main(sys.argv[1:]))
 
 # vim: ts=2:sw=2:tw=80:et: