diff options
| -rw-r--r-- | pym/emerge/__init__.py | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/pym/emerge/__init__.py b/pym/emerge/__init__.py index 8354da39f..2550da4c4 100644 --- a/pym/emerge/__init__.py +++ b/pym/emerge/__init__.py @@ -2246,6 +2246,26 @@ class depgraph(object): # failed to select any nodes. It is reset whenever nodes are # successfully selected. prefer_asap = True + + # By default, try to avoid selecting root nodes whenever possible. This + # helps ensure that the maximimum possible number of soft dependencies + # have been removed from the graph before their parent nodes have + # selected. This is especially important when those dependencies are + # going to be rebuilt by revdep-rebuild or `emerge -e system` after the + # CHOST has been changed (like when building a stage3 from a stage2). + accept_root_node = False + + # State of prefer_asap and accept_root_node flags for successive + # iterations that loosen the criteria for node selection. + # + # iteration prefer_asap accept_root_node + # 1 True False + # 2 False False + # 3 False True + # + # If no nodes are selected on the 4th iteration, it is due to + # unresolved blockers or circular dependencies. + while not mygraph.empty(): selected_nodes = None if prefer_asap and asap_nodes: @@ -2280,7 +2300,8 @@ class depgraph(object): # found a non-root node selected_nodes = [node] break - if not selected_nodes: + if not selected_nodes and \ + (accept_root_node or ignore_priority is None): # settle for a root node selected_nodes = [nodes[0]] if not selected_nodes: @@ -2313,6 +2334,9 @@ class depgraph(object): for ignore_priority in xrange(DepPriority.SOFT, DepPriority.MEDIUM_SOFT + 1): for node in nodes: + if not accept_root_node and \ + not mygraph.parent_nodes(node): + continue selected_nodes = set() if gather_deps(ignore_priority, mergeable_nodes, selected_nodes, node): @@ -2328,6 +2352,12 @@ class depgraph(object): prefer_asap = False continue + if not selected_nodes and not accept_root_node: + # Maybe there are only root nodes left, so accept them + # for the next iteration. + accept_root_node = True + continue + if selected_nodes and ignore_priority > DepPriority.SOFT: # Try to merge ignored medium deps as soon as possible. for node in selected_nodes: @@ -2408,8 +2438,10 @@ class depgraph(object): sys.exit(1) # At this point, we've succeeded in selecting one or more nodes, so - # it's now safe to reset the prefer_asap to it's default state. + # it's now safe to reset the prefer_asap and accept_root_node flags + # to their default states. prefer_asap = True + accept_root_node = False for node in selected_nodes: if node[-1] != "nomerge": |