Android: Maintain original order of sibling deps within .build_configs

This reduces randomness in the build by making our dependency
sorting a stable sort.

Bug: 828528, 828508
Change-Id: Ibf0f1de0d77333cdee575560912728e47b8f292e
Reviewed-on: https://chromium-review.googlesource.com/994545
Commit-Queue: agrieve <agrieve@chromium.org>
Reviewed-by: Samuel Huang <huangs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548131}

build/android/PRESUBMIT.py

@@ -58,6 +58,7 @@ def CommonChecks(input_api, output_api):
       output_api,
       unit_tests=[
           J('.', 'emma_coverage_stats_test.py'),
+          J('gyp', 'util', 'build_utils_test.py'),
           J('gyp', 'util', 'md5_check_test.py'),
           J('play_services', 'update_test.py'),
           J('pylib', 'gtest', 'gtest_test_instance_test.py'),

build/android/gyp/util/build_utils.py

@@ -3,6 +3,7 @@
 # found in the LICENSE file.
 
 import ast
+import collections
 import contextlib
 import fnmatch
 import json
@@ -395,37 +396,28 @@ def PrintBigWarning(message):
 def GetSortedTransitiveDependencies(top, deps_func):
   """Gets the list of all transitive dependencies in sorted order.
 
-  There should be no cycles in the dependency graph.
+  There should be no cycles in the dependency graph (crashes if cycles exist).
 
   Args:
-    top: a list of the top level nodes
-    deps_func: A function that takes a node and returns its direct dependencies.
+    top: A list of the top level nodes
+    deps_func: A function that takes a node and returns a list of its direct
+        dependencies.
   Returns:
     A list of all transitive dependencies of nodes in top, in order (a node will
     appear in the list at a higher index than all of its dependencies).
   """
-  def Node(dep):
-    return (dep, deps_func(dep))
-
-  # First: find all deps
-  unchecked_deps = list(top)
-  all_deps = set(top)
-  while unchecked_deps:
-    dep = unchecked_deps.pop()
-    new_deps = deps_func(dep).difference(all_deps)
-    unchecked_deps.extend(new_deps)
-    all_deps = all_deps.union(new_deps)
-
-  # Then: simple, slow topological sort.
-  sorted_deps = []
-  unsorted_deps = dict(map(Node, all_deps))
-  while unsorted_deps:
-    for library, dependencies in unsorted_deps.items():
-      if not dependencies.intersection(unsorted_deps.keys()):
-        sorted_deps.append(library)
-        del unsorted_deps[library]
-
-  return sorted_deps
+  # Find all deps depth-first, maintaining original order in the case of ties.
+  deps_map = collections.OrderedDict()
+  def discover(nodes):
+    for node in nodes:
+      if node in deps_map:
+        continue
+      deps = deps_func(node)
+      discover(deps)
+      deps_map[node] = deps
+
+  discover(top)
+  return deps_map.keys()
 
 
 def GetPythonDependencies():

build/android/gyp/util/build_utils_test.py

+#!/usr/bin/env python
+# Copyright 2018 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import collections
+import unittest
+
+import build_utils # pylint: disable=W0403
+
+_DEPS = collections.OrderedDict()
+_DEPS['a'] = []
+_DEPS['b'] = []
+_DEPS['c'] = ['a']
+_DEPS['d'] = ['a']
+_DEPS['e'] = ['f']
+_DEPS['f'] = ['a', 'd']
+_DEPS['g'] = []
+_DEPS['h'] = ['d', 'b', 'f']
+_DEPS['i'] = ['f']
+
+
+class BuildUtilsTest(unittest.TestCase):
+  def testGetSortedTransitiveDependencies_all(self):
+    TOP = _DEPS.keys()
+    EXPECTED = ['a', 'b', 'c', 'd', 'f', 'e', 'g', 'h', 'i']
+    actual = build_utils.GetSortedTransitiveDependencies(TOP, _DEPS.get)
+    self.assertEqual(EXPECTED, actual)
+
+  def testGetSortedTransitiveDependencies_leaves(self):
+    TOP = ['c', 'e', 'g', 'h', 'i']
+    EXPECTED = ['a', 'c', 'd', 'f', 'e', 'g', 'b', 'h', 'i']
+    actual = build_utils.GetSortedTransitiveDependencies(TOP, _DEPS.get)
+    self.assertEqual(EXPECTED, actual)
+
+  def testGetSortedTransitiveDependencies_leavesReverse(self):
+    TOP = ['i', 'h', 'g', 'e', 'c']
+    EXPECTED = ['a', 'd', 'f', 'i', 'b', 'h', 'g', 'e', 'c']
+    actual = build_utils.GetSortedTransitiveDependencies(TOP, _DEPS.get)
+    self.assertEqual(EXPECTED, actual)
+
+
+if __name__ == '__main__':
+  unittest.main()

build/android/gyp/write_build_config.py

@@ -562,7 +562,7 @@ def DepsOfType(wanted_type, configs):
 
 def GetAllDepsConfigsInOrder(deps_config_paths):
   def GetDeps(path):
-    return set(GetDepConfig(path)['deps_configs'])
+    return GetDepConfig(path)['deps_configs']
   return build_utils.GetSortedTransitiveDependencies(deps_config_paths, GetDeps)
 
 

build/android/gyp/write_ordered_libraries.py

@@ -48,11 +48,11 @@ def CallReadElf(library_or_executable):
 
 def GetDependencies(library_or_executable):
   elf = CallReadElf(library_or_executable)
-  deps = set()
+  deps = []
   for l in _library_re.findall(elf):
     p = _library_path_map.get(l)
     if p is not None:
-      deps.add(p)
+      deps.append(p)
   return deps