Remote: Fix file counting in merkletree.DirectoryTreeBuilder

The DirectoryTreeBuilder did not check if files already existed in the resulting map, so the file counter got wrong and an assertion failed.

The error was visible when adding a file and the directory containing that file as inputs for an action.

Fixes #14286.

Closes #14299.

PiperOrigin-RevId: 412051374

src/main/java/com/google/devtools/build/lib/remote/merkletree/DirectoryTree.java

@@ -147,8 +147,8 @@ static class DirectoryNode extends Node {
       super(pathSegment);
     }
 
-    void addChild(Node child) {
-      children.add(Preconditions.checkNotNull(child, "child"));
+    boolean addChild(Node child) {
+      return children.add(Preconditions.checkNotNull(child, "child"));
     }
 
     @Override

src/main/java/com/google/devtools/build/lib/remote/merkletree/DirectoryTreeBuilder.java

@@ -101,8 +101,9 @@ private static int buildFromPaths(
             throw new IOException(String.format("Input '%s' is not a file.", input));
           }
           Digest d = digestUtil.compute(input);
-          currDir.addChild(FileNode.createExecutable(path.getBaseName(), input, d));
-          return 1;
+          boolean childAdded =
+              currDir.addChild(FileNode.createExecutable(path.getBaseName(), input, d));
+          return childAdded ? 1 : 0;
         });
   }
 
@@ -127,9 +128,11 @@ private static int buildFromActionInputs(
           if (input instanceof VirtualActionInput) {
             VirtualActionInput virtualActionInput = (VirtualActionInput) input;
             Digest d = digestUtil.compute(virtualActionInput);
-            currDir.addChild(
-                FileNode.createExecutable(path.getBaseName(), virtualActionInput.getBytes(), d));
-            return 1;
+            boolean childAdded =
+                currDir.addChild(
+                    FileNode.createExecutable(
+                        path.getBaseName(), virtualActionInput.getBytes(), d));
+            return childAdded ? 1 : 0;
           }
 
           FileArtifactValue metadata =
@@ -141,8 +144,9 @@ private static int buildFromActionInputs(
             case REGULAR_FILE:
               Digest d = DigestUtil.buildDigest(metadata.getDigest(), metadata.getSize());
               Path inputPath = ActionInputHelper.toInputPath(input, execRoot);
-              currDir.addChild(FileNode.createExecutable(path.getBaseName(), inputPath, d));
-              return 1;
+              boolean childAdded =
+                  currDir.addChild(FileNode.createExecutable(path.getBaseName(), inputPath, d));
+              return childAdded ? 1 : 0;
 
             case DIRECTORY:
               SortedMap<PathFragment, ActionInput> directoryInputs =

src/test/java/com/google/devtools/build/lib/remote/merkletree/ActionInputDirectoryTreeTest.java

@@ -130,6 +130,43 @@ public void directoryInputShouldBeExpanded() throws Exception {
     assertThat(fileNodesAtDepth(tree, 3)).containsExactly(expectedBuzzNode);
   }
 
+  @Test
+  public void filesShouldBeDeduplicated() throws Exception {
+    // Test that a file specified as part of a directory and as an individual file is not counted
+    // twice.
+
+    SortedMap<PathFragment, ActionInput> sortedInputs = new TreeMap<>();
+    Map<ActionInput, FileArtifactValue> metadata = new HashMap<>();
+
+    Path dirPath = execRoot.getRelative("srcs");
+    dirPath.createDirectoryAndParents();
+    Artifact dir = ActionsTestUtil.createArtifact(artifactRoot, dirPath);
+    sortedInputs.put(dirPath.relativeTo(execRoot), dir);
+    metadata.put(dir, FileArtifactValue.createForTesting(dirPath));
+
+    Path fooPath = dirPath.getRelative("foo.cc");
+    FileSystemUtils.writeContentAsLatin1(fooPath, "foo");
+    ActionInput foo = ActionInputHelper.fromPath(fooPath.relativeTo(execRoot));
+    sortedInputs.put(fooPath.relativeTo(execRoot), foo);
+    metadata.put(foo, FileArtifactValue.createForTesting(fooPath));
+
+    DirectoryTree tree =
+        DirectoryTreeBuilder.fromActionInputs(
+            sortedInputs, new StaticMetadataProvider(metadata), execRoot, digestUtil);
+    assertLexicographicalOrder(tree);
+
+    assertThat(directoriesAtDepth(0, tree)).containsExactly("srcs");
+    assertThat(directoriesAtDepth(1, tree)).isEmpty();
+
+    FileNode expectedFooNode =
+        FileNode.createExecutable(
+            "foo.cc", execRoot.getRelative(foo.getExecPath()), digestUtil.computeAsUtf8("foo"));
+    assertThat(fileNodesAtDepth(tree, 0)).isEmpty();
+    assertThat(fileNodesAtDepth(tree, 1)).containsExactly(expectedFooNode);
+
+    assertThat(tree.numFiles()).isEqualTo(1);
+  }
+
   private static VirtualActionInput addVirtualFile(
       String path, String content, SortedMap<PathFragment, ActionInput> sortedInputs) {
     PathFragment pathFragment = PathFragment.create(path);