Merge 278b0ab into 85fd6a4

src/python/pants/backend/core/tasks/prepare_resources.py

@@ -42,8 +42,8 @@ def execute(self):
       self.context.products.safe_create_data('resources_by_target',
                                              lambda: defaultdict(MultipleRootedProducts))
 
-    # `targets` contains the transitive subgraph in pre-order, which is approximately how
-    # we want them ordered on the classpath. Thus, we preserve ordering here.
+    # NB: Ordering isn't relevant here, because it is applied during the dep walk to
+    # consume from the compile_classpath.
     targets = self.context.targets()
     if len(targets) == 0:
       return
@@ -82,7 +82,7 @@ def compute_target_dir(tgt):
         for conf in self.confs:
           # TODO(John Sirois): Introduce the notion of RuntimeClasspath and populate that product
           # instead of mutating the compile_classpath.
-          compile_classpath.add_for_targets(targets, [(conf, target_dir)])
+          compile_classpath.add_for_target(resources_tgt, [(conf, target_dir)])
         if resources_by_target is not None:
           resources_by_target[resources_tgt].add_rel_paths(
             target_dir, resources_tgt.sources_relative_to_source_root())

src/python/pants/base/build_graph.py

@@ -7,7 +7,7 @@
 
 import logging
 import traceback
-from collections import OrderedDict, defaultdict
+from collections import OrderedDict, defaultdict, deque
 
 from twitter.common.collections import OrderedSet
 
@@ -183,7 +183,7 @@ def sorted_targets(self):
     return sort_targets(self._target_by_address.values())
 
   def walk_transitive_dependency_graph(self, addresses, work, predicate=None, postorder=False):
-    """Given a work function, walks the transitive dependency closure of `addresses`.
+    """Given a work function, walks the transitive dependency closure of `addresses` using DFS.
 
     :param list<Address> addresses: The closure of `addresses` will be walked.
     :param function work: The function that will be called on every target in the closure using
@@ -263,6 +263,26 @@ def transitive_subgraph_of_addresses(self, addresses, predicate=None, postorder=
                                           postorder=postorder)
     return ret
 
+  def transitive_subgraph_of_addresses_bfs(self, addresses, predicate=None):
+    """Returns the transitive dependency closure of `addresses` using BFS.
+
+    :param list<Address> addresses: The closure of `addresses` will be walked.
+    :param function predicate: If this parameter is not given, no Targets will be filtered
+      out of the closure.  If it is given, any Target which fails the predicate will not be
+      walked, nor will its dependencies.  Thus predicate effectively trims out any subgraph
+      that would only be reachable through Targets that fail the predicate.
+    """
+    walked = OrderedSet()
+    to_walk = deque(addresses)
+    while len(to_walk) > 0:
+      address = to_walk.popleft()
+      target = self._target_by_address[address]
+      if target not in walked:
+        walked.add(target)
+        if not predicate or predicate(target):
+          to_walk.extend(self._target_dependencies_by_address[address])
+    return walked
+
   def inject_synthetic_target(self,
                               address,
                               target_type,

src/python/pants/base/target.py

@@ -418,9 +418,15 @@ def walk(self, work, predicate=None):
       raise ValueError('predicate must be callable but was {}'.format(predicate))
     self._build_graph.walk_transitive_dependency_graph([self.address], work, predicate)
 
-  def closure(self):
-    """Returns this target's transitive dependencies, in DFS preorder traversal."""
-    return self._build_graph.transitive_subgraph_of_addresses([self.address])
+  def closure(self, bfs=False):
+    """Returns this target's transitive dependencies.
+
+    The walk will be depth-first in preorder, or breadth first if bfs=True is specified.
+    """
+    if bfs:
+      return self._build_graph.transitive_subgraph_of_addresses_bfs([self.address])
+    else:
+      return self._build_graph.transitive_subgraph_of_addresses([self.address])
 
   # TODO(Eric Ayers) As of 2/5/2015 this call is DEPRECATED and should be removed soon
   def add_labels(self, *label):

src/python/pants/goal/products.py

@@ -35,9 +35,9 @@ def get_for_targets(self, targets):
     """Gets the transitive product deps for the given targets, in order."""
     products = OrderedSet()
     visited = set()
-    # Walk the targets transitively to aggregate their products.
+    # Walk the targets transitively to aggregate their products. We do a breadth-first
     for target in targets:
-      for dep in target.closure():
+      for dep in target.closure(bfs=True):
         if dep not in visited:
           products.update(self._products_by_target[dep])
           visited.add(dep)