Improve lookahead for new-style virtuals:

* Substitute the graph tree for the vartree in dep_check() since we
  want atom selections to be consistent with package selections
  that have already been made.
* Add the selected package to the graph as soon as possible
  so that later dep_check() calls can use it as feedback
  for making more consistent atom selections.
* Expand all slots of new-style virtuals inside _dep_check_composite_db
  so that lookahead examines all matched slots.

This solves some cases of bug #1343, and extends the fix for bug
#141118 to work in cases when a virtual is not yet installed but
it has been pulled into the graph.

(trunk r9873)

svn path=/main/branches/2.1.2/; revision=9877

diff --git a/bin/emerge b/bin/emerge
index 69a65cf075a0e92677ec6cf77ffd62f4dfa283d5..a2a27850a8c46fdefbad631adbd770500ca51c7b 100755 (executable)
--- a/bin/emerge
+++ b/bin/emerge
@@ -1742,7 +1742,11 @@ class depgraph(object):
                        self._graph_trees[myroot]["vartree"] = self.trees[myroot]["vartree"]
                        del vardb, fakedb
                        self._filtered_trees[myroot] = {}
-                       self._filtered_trees[myroot]["vartree"] = self.trees[myroot]["vartree"]
+                       # Substitute the graph tree for the vartree in dep_check() since we
+                       # want atom selections to be consistent with package selections
+                       # have already been made.
+                       self._filtered_trees[myroot]["vartree"] = \
+                               self._graph_trees[myroot]["porttree"]
                        def filtered_tree():
                                pass
                        filtered_tree.dbapi = self._dep_check_composite_db(self, myroot)
@@ -2579,8 +2583,17 @@ class depgraph(object):
                                                        arg.name in ("system", "world")):
                                                        return 0, myfavorites
 
-                                       self._dep_stack.append(
-                                               Dependency(atom=atom, onlydeps=onlydeps, root=myroot, parent=arg))
+                                       dep = Dependency(atom=atom, onlydeps=onlydeps,
+                                               root=myroot, parent=arg)
+                                       self._dep_stack.append(dep)
+
+                                       # Add the selected package to the graph as soon as possible
+                                       # so that later dep_check() calls can use it as feedback
+                                       # for making more consistent atom selections.
+                                       if not self._add_pkg(pkg, dep.parent,
+                                               priority=dep.priority, depth=dep.depth):
+                                               return 0, myfavorites
+
                                        if not self._create_graph():
                                                if isinstance(arg, SetArg):
                                                        sys.stderr.write(("\n\n!!! Problem resolving " + \
@@ -4513,12 +4526,20 @@ class depgraph(object):
                                slots = set()
                                slots.add(pkg.metadata["SLOT"])
                                atom_cp = portage.dep_getkey(atom)
-                               if atom_cp == pkg.cp:
-                                       graph_db = self._depgraph.mydbapi[self._root]
-                                       for cpv in graph_db.match(atom):
-                                               if portage.cpv_getkey(cpv) != pkg.cp:
-                                                       continue
-                                               slots.add(graph_db.aux_get(cpv, ["SLOT"])[0])
+                               if pkg.cp.startswith("virtual/"):
+                                       # For new-style virtual lookahead that occurs inside
+                                       # dep_check(), examine all slots. This is needed
+                                       # so that newer slots will not unnecessarily be pulled in
+                                       # when a satisfying lower slot is already installed. For
+                                       # example, if virtual/jdk-1.4 is satisfied via kaffe then
+                                       # there's no need to pull in a newer slot to satisfy a
+                                       # virtual/jdk dependency.
+                                       for db, pkg_type, built, installed, db_keys in \
+                                               self._depgraph._filtered_trees[self._root]["dbs"]:
+                                               for cpv in db.match(atom):
+                                                       if portage.cpv_getkey(cpv) != pkg.cp:
+                                                               continue
+                                                       slots.add(db.aux_get(cpv, ["SLOT"])[0])
                                ret = []
                                if self._visible(pkg):
                                        self._cpv_pkg_map[pkg.cpv] = pkg