Fix NoSuchElementException when BuildEventArtifactUploaderMap has no elements.

When there are no uploaders in BuildEventArtifactUploaderMap then we should use the BuildEventArtifactUploader.LOCAL_FILES_UPLOADER as a fallback. Added some unit tests as regression tests for the underlying issue.

PiperOrigin-RevId: 201529578

3 files changed, 66 insertions, 1 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/buildeventstream/BuildEventArtifactUploaderMap.java b/src/main/java/com/google/devtools/build/lib/buildeventstream/BuildEventArtifactUploaderMap.java
index 8987def882..e9f611ab9a 100644
--- a/src/main/java/com/google/devtools/build/lib/buildeventstream/BuildEventArtifactUploaderMap.java
+++ b/src/main/java/com/google/devtools/build/lib/buildeventstream/BuildEventArtifactUploaderMap.java
@@ -30,7 +30,7 @@ public class BuildEventArtifactUploaderMap {
   }
 
   public BuildEventArtifactUploader select(@Nullable String name) {
-    if (name == null) {
+    if (name == null && !uploaders.values().isEmpty()) {
       // TODO(b/110235226): We currently choose the strategy with alphabetically first strategy,
       // which happens to be backwards-compatible; we need to set
       // experimental_build_event_upload_strategy to appropriate default values instead, and then
diff --git a/src/test/java/com/google/devtools/build/lib/buildeventstream/BUILD b/src/test/java/com/google/devtools/build/lib/buildeventstream/BUILD
index 586bdff2c0..a23d3dd3ff 100644
--- a/src/test/java/com/google/devtools/build/lib/buildeventstream/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/buildeventstream/BUILD
@@ -17,6 +17,7 @@ java_test(
     runtime_deps = ["//src/test/java/com/google/devtools/build/lib:test_runner"],
     deps = [
         "//src/main/java/com/google/devtools/build/lib/buildeventstream",
+        "//src/main/java/com/google/devtools/build/lib/vfs",
         "//third_party:guava",
         "//third_party:junit4",
         "//third_party:mockito",
diff --git a/src/test/java/com/google/devtools/build/lib/buildeventstream/BuildEventArtifactUploaderMapTest.java b/src/test/java/com/google/devtools/build/lib/buildeventstream/BuildEventArtifactUploaderMapTest.java
new file mode 100644
index 0000000000..095c42dbda
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/buildeventstream/BuildEventArtifactUploaderMapTest.java
@@ -0,0 +1,64 @@
+// Copyright 2018 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.buildeventstream;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.devtools.build.lib.vfs.Path;
+import java.util.Set;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link BuildEventArtifactUploaderMap}. */
+@RunWith(JUnit4.class)
+public final class BuildEventArtifactUploaderMapTest {
+  private BuildEventArtifactUploaderMap uploader;
+  private BuildEventArtifactUploader noConversionUploader;
+
+  @Before
+  public void setUp() {
+    noConversionUploader =
+        new BuildEventArtifactUploader() {
+          @Override
+          public PathConverter upload(Set<Path> files) {
+            return PathConverter.NO_CONVERSION;
+          }
+        };
+    uploader =
+        new BuildEventArtifactUploaderMap.Builder()
+            .add("a", BuildEventArtifactUploader.LOCAL_FILES_UPLOADER)
+            .add("b", noConversionUploader)
+            .build();
+  }
+
+  @Test
+  public void testEmptyUploaders() throws Exception {
+    BuildEventArtifactUploaderMap emptyUploader =
+        new BuildEventArtifactUploaderMap.Builder().build();
+    assertThat(emptyUploader.select(null))
+        .isEqualTo(BuildEventArtifactUploader.LOCAL_FILES_UPLOADER);
+  }
+
+  @Test
+  public void testAlphabeticalOrder() throws Exception {
+    assertThat(uploader.select(null)).isEqualTo(BuildEventArtifactUploader.LOCAL_FILES_UPLOADER);
+  }
+
+  @Test
+  public void testSelectByName() throws Exception {
+    assertThat(uploader.select("b")).isEqualTo(noConversionUploader);
+  }
+}