From fecc6af2264ea2d62121bc545fe7817c26956058 Mon Sep 17 00:00:00 2001
From: Zac Medico <zmedico@gentoo.org>
Date: Sat, 31 May 2008 02:08:25 +0000
Subject: Optimize the new --skipfirst code so that in only has to build a new
 depgraph one time when there are unsatisfied deps. This works by recursively
 traversing the digraph to remove the parent packages whose deps become
 unsatisfied when their dependencies are pruned from the mergelist. (trunk
 r10512:10514)

svn path=/main/branches/2.1.2/; revision=10515
---
 bin/emerge | 44 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 37 insertions(+), 7 deletions(-)

(limited to 'bin')

diff --git a/bin/emerge b/bin/emerge
index 72955612f..a1761e7e7 100755
--- a/bin/emerge
+++ b/bin/emerge
@@ -8314,19 +8314,49 @@ def action_build(settings, trees, mtimedb,
 				except depgraph.UnsatisfiedResumeDep, e:
 					if "--skipfirst" not in myopts:
 						raise
-					unsatisfied_parents = set(dep.parent for dep in e.value)
-					pruned_mergelist = []
-					for task in mergelist:
-						if isinstance(task, list) and \
-							tuple(task) in unsatisfied_parents:
+
+					graph = mydepgraph.digraph
+					unsatisfied_parents = dict((dep.parent, dep.parent) \
+						for dep in e.value)
+					traversed_nodes = set()
+					unsatisfied_stack = list(unsatisfied_parents)
+					while unsatisfied_stack:
+						pkg = unsatisfied_stack.pop()
+						if pkg in traversed_nodes:
 							continue
-						pruned_mergelist.append(task)
+						traversed_nodes.add(pkg)
+
+						# If this package was pulled in by a parent
+						# package scheduled for merge, removing this
+						# package may cause the the parent package's
+						# dependency to become unsatisfied.
+						for parent_node in graph.parent_nodes(pkg):
+							if not isinstance(parent_node, Package) \
+								or parent_node.operation != "merge":
+								continue
+							unsatisfied = \
+								graph.child_nodes(parent_node,
+								ignore_priority=DepPriority.SOFT)
+							if pkg in unsatisfied:
+								unsatisfied_parents[parent_node] = parent_node
+								unsatisfied_stack.append(parent_node)
+
+					pruned_mergelist = [x for x in mergelist \
+						if isinstance(x, list) and \
+						tuple(x) not in unsatisfied_parents]
+
+					# It shouldn't happen, but if the size of mergelist
+					# does not decrease for some reason then the loop
+					# will be infinite. Therefore, if that case ever
+					# occurs for some reason, raise the exception to
+					# break out of the loop.
 					if not pruned_mergelist or \
 						len(pruned_mergelist) == len(mergelist):
 						raise
 					mergelist[:] = pruned_mergelist
 					dropped_tasks.update(unsatisfied_parents)
-					del e, unsatisfied_parents
+					del e, graph, traversed_nodes, \
+						unsatisfied_parents, unsatisfied_stack
 					continue
 				else:
 					break
-- 
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