Correct the order in which OutputDirectory and IntermediateDirectory are defined.

pylib/gyp/xcode_emulation.py

 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 This module contains classes that help to emulate xcodebuild behavior on top of
 other build systems, such as make and ninja.
 """
 
 import gyp.common
@@ skipping 943 matching lines @@
     str = str.replace(to_replace, '${' + variable + '}')
 
   return str
 
 
 def ExpandEnvVars(string, expansions):
   """Expands ${VARIABLES}, $(VARIABLES), and $VARIABLES in string per the
   expansions dict. If the variable expands to something that references
   another variable, this variable is expanded as well if it's in env --
   until no variables present in env are left."""
-  for k in reversed(TopologicallySortedEnvVarKeys(expansions)):
+  for k in TopologicallySortedEnvVarKeys(expansions):

[Nico, 2012/05/11 19:03:34]

You removed a reversed() here. That should probably return?

[bradn, 2012/05/11 20:10:31]

Done.
Ah yes, that's likely it.

     string = string.replace('${' + k + '}', expansions[k])
     string = string.replace('$(' + k + ')', expansions[k])
     string = string.replace('$' + k, expansions[k])
   return string
 
 
 def TopologicallySortedEnvVarKeys(env):
   """Takes a dict |env| whose values are strings that can refer to other keys,
   for example env['foo'] = '$(bar) and $(baz)'. Returns a list L of all keys of
   env such that key2 is after key1 in L if env[key2] refers to env[key1].

[Nico, 2012/05/11 19:03:34]

Undo comment change

[bradn, 2012/05/11 20:10:31]

? this has no diff now?

 
   Throws an Exception in case of dependency cycles.
   """
   # Since environment variables can refer to other variables, the evaluation
   # order is important. Below is the logic to compute the dependency graph
   # and sort it.
   regex = re.compile(r'\$\{([a-zA-Z0-9\-_]+)\}')
-
-  # First sort the list of keys.
-  key_list = sorted(env.keys())
-
-  # Phase 1: Create a set of edges of (DEPENDEE, DEPENDER) where in the graph,
-  # DEPENDEE -> DEPENDER. Also create sets of dependers and dependees.
-  edges = set()
-  dependees = set()
-  dependers = set()
-  for k in key_list:
-    matches = regex.findall(env[k])
-    if not len(matches):
-      continue
-
-    depends_on_other_var = False
+  def GetEdges(node):
+    # Use a definition of edges such that user_of_variable -> used_varible.
+    # This happens to be easier in this case, since a variable's
+    # definition contains all variables it references in a single string.
+    # We can then reverse the result of the topological sort at the end.
+    # Since: reverse(topsort(DAG)) = topsort(reverse_edges(DAG))
+    matches = set([v for v in regex.findall(env[node]) if v in env])
     for dependee in matches:
       assert '${' not in dependee, 'Nested variables not supported: ' + dependee
-      if dependee in env:
-        edges.add((dependee, k))
-        dependees.add(dependee)
-        depends_on_other_var = True
-    if depends_on_other_var:
-      dependers.add(k)
+    return matches
 
-  # Phase 2: Create a list of graph nodes with no incoming edges.
-  sorted_nodes = []
-  edgeless_nodes = dependees - dependers
-
-  # Phase 3: Perform Kahn topological sort.
-  while len(edgeless_nodes):
-    # Find a node with no incoming edges, add it to the sorted list, and
-    # remove it from the list of nodes that aren't part of the graph.
-    node = edgeless_nodes.pop()
-    sorted_nodes.append(node)
-    key_list.remove(node)
-
-    # Find all the edges between |node| and other nodes.
-    edges_to_node = [e for e in edges if e[0] == node]
-    for edge in edges_to_node:
-      edges.remove(edge)
-      # If the node connected to |node| by |edge| has no other incoming edges,
-      # add it to |edgeless_nodes|.
-      if not len([e for e in edges if e[1] == edge[1]]):
-        edgeless_nodes.add(edge[1])
-
-  # Any remaining edges indicate a cycle.
-  if len(edges):
-    raise Exception('Xcode environment variables are cyclically dependent: ' +
-        str(edges))
-
-  # Append the "nodes" not in the graph to those that were just sorted.
-  sorted_nodes.extend(key_list)
-
-  return sorted_nodes
+  try:
+    # Topologically sort, and then reverse, because we used an edge definition
+    # that's inverted from the expected result of this function (see comment
+    # above).
+    order = gyp.common.TopologicallySorted(env.keys(), GetEdges)

[Nico, 2012/05/11 19:03:34]

nit: i'd just write `return reversed(gyp.common.TopoSort...`

[bradn, 2012/05/11 20:10:31]

So I'm generally avoiding reversed() when its stuffed away because unfortunately
reversed(reversed(x)) gives an error because reversed() returns an iterator
(which itself cannot be reversed). (Also the above reintroduction of reversed
precludes this.)

+    order.reverse()
+    return order
+  except CycleError, e:
+    raise Exception(
+        'Xcode environment variables are cyclically dependent: ' + str(e.nodes))
 
 
 def GetSpecPostbuildCommands(spec, quiet=False):
   """Returns the list of postbuilds explicitly defined on |spec|, in a form
   executable by a shell."""
   postbuilds = []
   for postbuild in spec.get('postbuilds', []):
     if not quiet:
       postbuilds.append('echo POSTBUILD\\(%s\\) %s' % (
             spec['target_name'], postbuild['postbuild_name']))
     postbuilds.append(gyp.common.EncodePOSIXShellList(postbuild['action']))
   return postbuilds