diff options
| -rw-r--r-- | pym/_emerge/depgraph.py | 97 |
1 files changed, 61 insertions, 36 deletions
diff --git a/pym/_emerge/depgraph.py b/pym/_emerge/depgraph.py index b086fe824..4095bbbba 100644 --- a/pym/_emerge/depgraph.py +++ b/pym/_emerge/depgraph.py @@ -891,47 +891,71 @@ class depgraph(object): self._add_parent_atom(pkg, parent_atom) self._process_slot_conflicts() + backtrack_data = [] + fallback_data = [] all_parents = set() - for node in (existing_node, pkg): + # The ordering of backtrack_data can make + # a difference here, because both mask actions may lead + # to valid, but different, solutions and the one with + # 'existing_node' masked is usually the better one. Because + # of that, we choose an order such that + # the backtracker will first explore the choice with + # existing_node masked. The backtracker reverses the + # order, so the order it uses is the reverse of the + # order shown here. See bug #339606. + for to_be_selected, to_be_masked in (existing_node, pkg), (pkg, existing_node): + # For missed update messages, find out which + # atoms matched to_be_selected that did not + # match to_be_masked. parent_atoms = \ - self._dynamic_config._parent_atoms.get(node, set()) + self._dynamic_config._parent_atoms.get(to_be_selected, set()) if parent_atoms: conflict_atoms = self._dynamic_config._slot_conflict_parent_atoms.intersection(parent_atoms) if conflict_atoms: parent_atoms = conflict_atoms + all_parents.update(parent_atoms) - # NOTE: Generally, we mask the higher version since - # this solves common cases in which a lower version - # is needed so that all dependencies will be - # satisfied (bug #337178). However, if existing_node - # happens to be installed then we mask that since - # this is a common case that is triggered when - # --update is not enabled. - if existing_node.installed: - to_be_masked = existing_node - to_be_selected = pkg - elif pkg > existing_node: - to_be_masked = pkg - to_be_selected = existing_node - else: - to_be_masked = existing_node - to_be_selected = pkg - - # For missed update messages, find out which - # atoms matched to_be_selected that did not - # match to_be_masked. - parent_atoms = \ - self._dynamic_config._parent_atoms.get(to_be_selected, set()) - if parent_atoms: - conflict_atoms = self._dynamic_config._slot_conflict_parent_atoms.intersection(parent_atoms) - if conflict_atoms: - parent_atoms = conflict_atoms - - if to_be_selected >= to_be_masked: - # We only care about the parent atoms - # when they trigger a downgrade. - parent_atoms = set() + all_match = True + for parent, atom in parent_atoms: + i = InternalPackageSet(initial_atoms=(atom,)) + if not i.findAtomForPackage(to_be_masked): + all_match = False + break + + if to_be_selected >= to_be_masked: + # We only care about the parent atoms + # when they trigger a downgrade. + parent_atoms = set() + + fallback_data.append((to_be_masked, parent_atoms)) + + if all_match: + # 'to_be_masked' does not violate any parent atom, which means + # there is no point in masking it. + pass + else: + backtrack_data.append((to_be_masked, parent_atoms)) + + if not backtrack_data: + # This shouldn't happen, but fall back to the old + # behavior if this gets triggered somehow. + backtrack_data = fallback_data + + if len(backtrack_data) > 1: + # NOTE: Generally, we prefer to mask the higher + # version since this solves common cases in which a + # lower version is needed so that all dependencies + # will be satisfied (bug #337178). However, if + # existing_node happens to be installed then we + # mask that since this is a common case that is + # triggered when --update is not enabled. + if existing_node.installed: + pass + elif pkg > existing_node: + backtrack_data.reverse() + + to_be_masked, parent_atoms = backtrack_data[-1] self._dynamic_config._runtime_pkg_mask.setdefault( to_be_masked, {})["slot conflict"] = parent_atoms @@ -941,13 +965,14 @@ class depgraph(object): msg.append("") msg.append("") msg.append("backtracking due to slot conflict:") + if backtrack_data is fallback_data: + msg.append("!!! backtrack_data fallback") msg.append(" first package: %s" % existing_node) msg.append(" second package: %s" % pkg) msg.append(" package to mask: %s" % to_be_masked) msg.append(" slot: %s" % pkg.slot_atom) - msg.append(" parents: %s" % \ - [(str(parent), atom) \ - for parent, atom in all_parents]) + msg.append(" parents: %s" % ", ".join( \ + "(%s, '%s')" % (ppkg, atom) for ppkg, atom in all_parents)) msg.append("") writemsg_level("".join("%s\n" % l for l in msg), noiselevel=-1, level=logging.DEBUG) |