Bug #253904 - Add a lookahead mechanism inside

depgraph._dep_check_composite_db._visible() which masks package choices
that are likely to trigger slot conflicts. Thanks to Vlastimil Babka
<caster@g.o> for the suggestion.
(trunk r12622:12624)

svn path=/main/branches/2.1.6/; revision=12898

diff --git a/pym/_emerge/__init__.py b/pym/_emerge/__init__.py
index dc848fc9db1f942a5334c6fee879ba1bb1ed2336..16da537d0fdb8e2736e1bd1a60090c7b4d31a33b 100644 (file)
--- a/pym/_emerge/__init__.py
+++ b/pym/_emerge/__init__.py
@@ -5051,9 +5051,10 @@ class depgraph(object):
                                # dependencies so that things like --fetchonly can still
                                # function despite collisions.
                                pass
-                       else:
+                       elif not previously_added:
                                self._slot_pkg_map[pkg.root][pkg.slot_atom] = pkg
                                self.mydbapi[pkg.root].cpv_inject(pkg)
+                               self._filtered_trees[pkg.root]["porttree"].dbapi._clear_cache()
 
                        if not pkg.installed:
                                # Allow this package to satisfy old-style virtuals in case it
@@ -8881,6 +8882,20 @@ class depgraph(object):
                                                return False
                                except portage.exception.InvalidDependString:
                                        pass
+                       in_graph = self._depgraph._slot_pkg_map[
+                               self._root].get(pkg.slot_atom)
+                       if in_graph is None:
+                               # Mask choices for packages which are not the highest visible
+                               # version within their slot (since they usually trigger slot
+                               # conflicts).
+                               highest_visible, in_graph = self._depgraph._select_package(
+                                       self._root, pkg.slot_atom)
+                               if pkg != highest_visible:
+                                       return False
+                       elif in_graph != pkg:
+                               # Mask choices for packages that would trigger a slot
+                               # conflict with a previously selected package.
+                               return False
                        return True
 
                def _dep_expand(self, atom):