From 518f53210ffe4e5ea0e5b5fcac1f7916133da11b Mon Sep 17 00:00:00 2001
From: kaipi <kaipi@google.com>
Date: Wed, 31 Jan 2018 10:22:00 -0800
Subject: [PATCH] Order the input-output map keys before processing its
 elements. This fixes non-determinism in how the protos get bundled into the
 BundledProtos_X archives.

PiperOrigin-RevId: 184009755
---
 .../build/lib/rules/objc/ProtobufSupport.java | 23 +++++++++++++++----
 1 file changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ProtobufSupport.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ProtobufSupport.java
index 4c7bb874007a26..1d046dfafbcb47 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ProtobufSupport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ProtobufSupport.java
@@ -41,6 +41,7 @@
 import com.google.devtools.build.lib.vfs.PathFragment;
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 
 /**
@@ -164,7 +165,7 @@ public ProtobufSupport(
   public ProtobufSupport registerGenerationActions() {
     int actionId = 0;
 
-    for (ImmutableSet<Artifact> inputProtos : inputsToOutputsMap.keySet()) {
+    for (ImmutableSet<Artifact> inputProtos : orderedInputOutputKeySet()) {
       Iterable<Artifact> outputProtos = inputsToOutputsMap.get(inputProtos);
       registerGenerationAction(outputProtos, inputProtos, getUniqueBundledProtosSuffix(actionId));
       actionId++;
@@ -203,7 +204,7 @@ public ProtobufSupport registerCompilationActions()
     int actionId = 0;
     Iterable<PathFragment> userHeaderSearchPaths =
         ImmutableList.of(getWorkspaceRelativeOutputDir());
-    for (ImmutableSet<Artifact> inputProtos : inputsToOutputsMap.keySet()) {
+    for (ImmutableSet<Artifact> inputProtos : orderedInputOutputKeySet()) {
       ImmutableSet<Artifact> outputProtos = inputsToOutputsMap.get(inputProtos);
 
       IntermediateArtifacts intermediateArtifacts = getUniqueIntermediateArtifacts(actionId);
@@ -243,7 +244,7 @@ public ProtobufSupport addFilesToBuild(NestedSetBuilder<Artifact> filesToBuild)
     }
 
     int actionId = 0;
-    for (ImmutableSet<Artifact> inputProtos : inputsToOutputsMap.keySet()) {
+    for (ImmutableSet<Artifact> inputProtos : orderedInputOutputKeySet()) {
       ImmutableSet<Artifact> outputProtos = inputsToOutputsMap.get(inputProtos);
       IntermediateArtifacts intermediateArtifacts = getUniqueIntermediateArtifacts(actionId);
 
@@ -275,7 +276,7 @@ public Optional<ObjcProvider> getObjcProvider() {
     }
 
     int actionId = 0;
-    for (ImmutableSet<Artifact> inputProtos : inputsToOutputsMap.keySet()) {
+    for (ImmutableSet<Artifact> inputProtos : orderedInputOutputKeySet()) {
       ImmutableSet<Artifact> outputProtos = inputsToOutputsMap.get(inputProtos);
       IntermediateArtifacts intermediateArtifacts = getUniqueIntermediateArtifacts(actionId);
 
@@ -372,6 +373,20 @@ private static ImmutableSetMultimap<ImmutableSet<Artifact>, Artifact> getInputsT
     return inputsToOutputsMapBuilder.build();
   }
 
+  /**
+   * Returns an ordered list of ImmutableSets<Artifact>s representing the keys to the inputs-outputs
+   * map. Using an ordered list ensures that for the same inputs, the keys are processed in the same
+   * order, and avoids non-determinism in the intermediate outputs.
+   */
+  private List<ImmutableSet<Artifact>> orderedInputOutputKeySet() {
+    return new Ordering<ImmutableSet<Artifact>>() {
+      @Override
+      public int compare(ImmutableSet<Artifact> o1, ImmutableSet<Artifact> o2) {
+        return o1.hashCode() - o2.hashCode();
+      }
+    }.sortedCopy(inputsToOutputsMap.keySet());
+  }
+
   private String getBundledProtosSuffix() {
     return "_" + BUNDLED_PROTOS_IDENTIFIER;
   }