Download directory output for test actions (#18846)

This is a dedicated fix for #17884 for 6.3.0.

Fixes #18845.

src/main/java/com/google/devtools/build/lib/remote/ToplevelArtifactsDownloader.java

@@ -47,8 +47,10 @@
 import com.google.devtools.build.lib.skyframe.TreeArtifactValue;
 import com.google.devtools.build.lib.util.Pair;
 import com.google.devtools.build.lib.vfs.Path;
+import com.google.devtools.build.lib.vfs.Symlinks;
 import com.google.devtools.build.skyframe.MemoizingEvaluator;
 import com.google.devtools.build.skyframe.SkyValue;
+import java.io.IOException;
 import java.util.HashMap;
 import javax.annotation.Nullable;
 
@@ -117,6 +119,18 @@ public interface PathToMetadataConverter {
   }
 
   private void downloadTestOutput(Path path) {
+    if (path.isDirectory()) {
+      try {
+        var entries = path.readdir(Symlinks.FOLLOW);
+        for (var entry : entries) {
+          downloadTestOutput(path.getRelative(entry.getName()));
+          return;
+        }
+      } catch (IOException e) {
+        logger.atWarning().withCause(e).log("Failed to read dir %s.", path);
+      }
+    }
+
     // Since the event is fired within action execution, the skyframe doesn't know the outputs of
     // test actions yet, so we can't get their metadata through skyframe. However, the fileSystem
     // of the path is an ActionFileSystem, we use it to get the metadata for this file.

src/test/shell/bazel/remote/build_without_the_bytes_test.sh

@@ -685,6 +685,31 @@ EOF
   expect_log "test.outputs_manifest__MANIFEST"
 }
 
+function test_nozip_undeclared_test_outputs() {
+  mkdir -p a
+  cat > a/test.sh << 'EOF'
+#!/bin/sh
+echo foo > "$TEST_UNDECLARED_OUTPUTS_DIR/text.txt"
+EOF
+  chmod +x a/test.sh
+
+  cat > a/BUILD <<'EOF'
+sh_test(
+  name = "foo",
+  srcs = ["test.sh"],
+)
+EOF
+
+  bazel test \
+    --remote_executor=grpc://localhost:${worker_port} \
+    --remote_download_toplevel \
+    --nozip_undeclared_test_outputs \
+    //a:foo || fail "Failed to test //a:foo"
+
+  [[ -e "bazel-testlogs/a/foo/test.outputs/text.txt" ]] || fail "bazel-testlogs/a/foo/test.outputs/text.txt does not exist"
+  assert_contains "foo" "bazel-testlogs/a/foo/test.outputs/text.txt"
+}
+
 function test_multiple_test_attempts() {
   # Test that test logs of multiple test attempts can be renamed and reported by
   # BEP.