Remove ActionTemplate.getOutputTreeArtifact() and bubble it up to the subclasses that implement ActionTemplate where needed. #getOutputTreeArtifact() is mainly a convenience method to access one of the underlying output tree artifacts in tests, and has no contractual significance in the expansion of the ActionTemplate.

OTOH, `#getOutputs` is the main method that drives the logic (validation of the `ActionTemplate`) within `ActionTemplateExpansionFunction` and holds contractual significance whereby outputs of expanded actions need to be children `TreeFileArtifacts` of `#getOutputs()`.

RELNOTES: None.
PiperOrigin-RevId: 808640815
Change-Id: Ied5e577a0c8a674cd6910d091b284830ff6e500c

Author: zhengwei143

src/main/java/com/google/devtools/build/lib/actions/ActionTemplate.java

@@ -18,7 +18,6 @@
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.actions.Artifact.SpecialArtifact;
 import com.google.devtools.build.lib.actions.Artifact.TreeFileArtifact;
 import com.google.devtools.build.lib.analysis.platform.PlatformInfo;
@@ -92,26 +91,14 @@ ImmutableList<T> generateActionsForInputArtifacts(
         .collect(toImmutableListMultimap(TreeFileArtifact::getParent, x -> x));
   }
 
-  /** Returns the output TreeArtifact. */
-  SpecialArtifact getOutputTreeArtifact();
-
   @Override
   default SpecialArtifact getPrimaryInput() {
     return getInputTreeArtifacts().get(0);
   }
 
-  /**
-   * By default, returns just {@link #getOutputTreeArtifact}, but may be overridden with additional
-   * tree artifacts.
-   */
-  @Override
-  default ImmutableSet<Artifact> getOutputs() {
-    return ImmutableSet.of(getOutputTreeArtifact());
-  }
-
   @Override
-  default SpecialArtifact getPrimaryOutput() {
-    return getOutputTreeArtifact();
+  default Artifact getPrimaryOutput() {
+    return getOutputs().iterator().next();
   }
 
   @Override

src/main/java/com/google/devtools/build/lib/analysis/actions/SpawnActionTemplate.java

@@ -176,8 +176,8 @@ public ImmutableList<SpecialArtifact> getInputTreeArtifacts() {
   }
 
   @Override
-  public SpecialArtifact getOutputTreeArtifact() {
-    return outputTreeArtifact;
+  public ImmutableSet<Artifact> getOutputs() {
+    return ImmutableSet.of(outputTreeArtifact);
   }
 
   @Override

src/main/java/com/google/devtools/build/lib/analysis/actions/StarlarkActionTemplate.java

@@ -165,11 +165,6 @@ public ImmutableList<SpecialArtifact> getInputTreeArtifacts() {
     return ImmutableList.of(inputTreeArtifact);
   }
 
-  @Override
-  public SpecialArtifact getOutputTreeArtifact() {
-    return outputTreeArtifact;
-  }
-
   @Override
   public ImmutableSet<Artifact> getOutputs() {
     return ImmutableSet.copyOf(allOutputs);

src/main/java/com/google/devtools/build/lib/rules/cpp/CppCompileActionTemplate.java

@@ -302,11 +302,6 @@ public ImmutableList<SpecialArtifact> getInputTreeArtifacts() {
     return ImmutableList.of(sourceTreeArtifact);
   }
 
-  @Override
-  public SpecialArtifact getOutputTreeArtifact() {
-    return outputTreeArtifact;
-  }
-
   @Override
   public ActionOwner getOwner() {
     return actionOwner;

src/main/java/com/google/devtools/build/lib/rules/cpp/LtoBackendActionTemplate.java

@@ -363,11 +363,6 @@ public ImmutableList<SpecialArtifact> getInputTreeArtifacts() {
     return ImmutableList.of(firstNonNull(indexAndImportsTreeArtifact, fullBitcodeTreeArtifact));
   }
 
-  @Override
-  public SpecialArtifact getOutputTreeArtifact() {
-    return objectFileTreeArtifact;
-  }
-
   @Override
   public ActionOwner getOwner() {
     return actionOwner;

src/main/java/com/google/devtools/build/lib/skyframe/ActionTemplateExpansionFunction.java

@@ -39,10 +39,10 @@
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
 import com.google.devtools.build.skyframe.SkyframeLookupResult;
+import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import javax.annotation.Nullable;
 
 /**
@@ -141,7 +141,7 @@ private static ImmutableList<ActionAnalysisMetadata> generateAndValidateActionsF
       ImmutableList<TreeFileArtifact> inputTreeFileArtifacts,
       ActionTemplateExpansionKey key)
       throws ActionExecutionException, InterruptedException {
-    Set<Artifact> outputs = actionTemplate.getOutputs();
+    Collection<Artifact> outputs = actionTemplate.getOutputs();
     for (Artifact output : outputs) {
       Preconditions.checkState(
           output.isTreeArtifact(),

src/test/java/com/google/devtools/build/lib/skyframe/ActionTemplateExpansionFunctionTest.java

@@ -469,8 +469,8 @@ public ImmutableList<SpecialArtifact> getInputTreeArtifacts() {
     }
 
     @Override
-    public SpecialArtifact getOutputTreeArtifact() {
-      return outputTreeArtifact;
+    public ImmutableSet<Artifact> getOutputs() {
+      return ImmutableSet.of(outputTreeArtifact);
     }
 
     @Override

src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTest.java

@@ -56,6 +56,7 @@
 import com.google.devtools.build.skyframe.SkyFunction;
 import com.google.devtools.build.skyframe.SkyKey;
 import com.google.devtools.build.skyframe.SkyValue;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.HashMap;
@@ -177,9 +178,9 @@ public void testSpawnActionTemplate() throws Throwable {
         ActionsTestUtil.createDummySpawnActionTemplate(artifact1, artifact2);
     actions.add(actionTemplate);
     TreeFileArtifact treeFileArtifact1 =
-        createFakeExpansionTreeFileArtifact(actionTemplate, "child1", "hello1");
+        createFakeExpansionTreeFileArtifact(actionTemplate, artifact2, "child1", "hello1");
     TreeFileArtifact treeFileArtifact2 =
-        createFakeExpansionTreeFileArtifact(actionTemplate, "child2", "hello2");
+        createFakeExpansionTreeFileArtifact(actionTemplate, artifact2, "child2", "hello2");
 
     TreeArtifactValue value = (TreeArtifactValue) evaluateArtifactValue(artifact2);
     assertThat(value.getChildValues()).containsKey(treeFileArtifact1);
@@ -200,18 +201,18 @@ public void testConsecutiveSpawnActionTemplates() throws Throwable {
     SpawnActionTemplate template2 =
         ActionsTestUtil.createDummySpawnActionTemplate(artifact1, artifact2);
     actions.add(template2);
-    createFakeExpansionTreeFileArtifact(template2, "child1", "hello1");
-    createFakeExpansionTreeFileArtifact(template2, "child2", "hello2");
+    createFakeExpansionTreeFileArtifact(template2, artifact2, "child1", "hello1");
+    createFakeExpansionTreeFileArtifact(template2, artifact2, "child2", "hello2");
 
     // artifact3 is a tree artifact generated by action template.
     SpecialArtifact artifact3 = createDerivedTreeArtifactOnly("treeArtifact3");
     SpawnActionTemplate template3 =
         ActionsTestUtil.createDummySpawnActionTemplate(artifact2, artifact3);
     actions.add(template3);
     TreeFileArtifact treeFileArtifact1 =
-        createFakeExpansionTreeFileArtifact(template3, "child1", "hello1");
+        createFakeExpansionTreeFileArtifact(template3, artifact3, "child1", "hello1");
     TreeFileArtifact treeFileArtifact2 =
-        createFakeExpansionTreeFileArtifact(template3, "child2", "hello2");
+        createFakeExpansionTreeFileArtifact(template3, artifact3, "child2", "hello2");
 
     TreeArtifactValue value = (TreeArtifactValue) evaluateArtifactValue(artifact3);
     assertThat(value.getChildValues()).containsKey(treeFileArtifact1);
@@ -266,14 +267,18 @@ private static TreeFileArtifact createFakeTreeFileArtifact(
     return treeFileArtifact;
   }
 
+  @CanIgnoreReturnValue
   private TreeFileArtifact createFakeExpansionTreeFileArtifact(
-      ActionTemplate<?> actionTemplate, String parentRelativePath, String content)
+      ActionTemplate<?> actionTemplate,
+      SpecialArtifact outputTreeArtifact,
+      String parentRelativePath,
+      String content)
       throws Exception {
     int actionIndex = Iterables.indexOf(actions, actionTemplate::equals);
     Preconditions.checkState(actionIndex >= 0, "%s not registered", actionTemplate);
     TreeFileArtifact treeFileArtifact =
         TreeFileArtifact.createTemplateExpansionOutput(
-            actionTemplate.getOutputTreeArtifact(),
+            outputTreeArtifact,
             parentRelativePath,
             ActionTemplateExpansionValue.key(ALL_OWNER, actionIndex));
     Path path = treeFileArtifact.getPath();

src/test/java/com/google/devtools/build/lib/skyframe/SequencedSkyframeExecutorTest.java

@@ -1413,8 +1413,8 @@ public ImmutableList<SpecialArtifact> getInputTreeArtifacts() {
     }
 
     @Override
-    public SpecialArtifact getOutputTreeArtifact() {
-      return outputArtifact;
+    public ImmutableSet<Artifact> getOutputs() {
+      return ImmutableSet.of(outputArtifact);
     }
 
     @Override