Allow ImmutableList (and any type that extends List) to be the type o…

…f an option with allowMultiple = true.

PiperOrigin-RevId: 436517607

src/main/java/com/google/devtools/common/options/processor/OptionProcessor.java

@@ -190,12 +190,11 @@ private ImmutableList<TypeMirror> getAcceptedConverterReturnTypes(VariableElemen
             optionType);
       }
       DeclaredType optionDeclaredType = (DeclaredType) optionType;
-      // optionDeclaredType.asElement().asType() gets us from List<actualType> to List<E>, so this
-      // is unfortunately necessary.
-      if (!typeUtils.isAssignable(optionDeclaredType.asElement().asType(), listType)) {
+      if (!typeUtils.isAssignable(typeUtils.erasure(optionDeclaredType), listType)) {
         throw new OptionProcessorException(
             optionField,
-            "Option that allows multiple occurrences must be of type %s, but is of type %s",
+            "Option that allows multiple occurrences must be assignable to type %s, but is of type"
+                + " %s",
             listType,
             optionType);
       }

src/test/java/com/google/devtools/common/options/processor/OptionProcessorTest.java

@@ -236,8 +236,8 @@ public void allowMultipleOptionWithCollectionTypeIsRejected() {
         .processedWith(new OptionProcessor())
         .failsToCompile()
         .withErrorContaining(
-            "Option that allows multiple occurrences must be of type java.util.List<E>, "
-                + "but is of type java.util.Collection<java.lang.String>");
+            "Option that allows multiple occurrences must be assignable to type java.util.List<E>,"
+                + " but is of type java.util.Collection<java.lang.String>");
   }
 
   @Test
@@ -247,8 +247,16 @@ public void allowMultipleOptionWithNonListTypeIsRejected() {
         .processedWith(new OptionProcessor())
         .failsToCompile()
         .withErrorContaining(
-            "Option that allows multiple occurrences must be of type java.util.List<E>, "
-                + "but is of type java.lang.String");
+            "Option that allows multiple occurrences must be assignable to type java.util.List<E>,"
+                + " but is of type java.lang.String");
+  }
+
+  @Test
+  public void allowMultipleOptionWithImmutableListTypeIsAllowed() {
+    assertAbout(javaSource())
+        .that(getFile("ImmutableListTypeForAllowMultipleOption.java"))
+        .processedWith(new OptionProcessor())
+        .compilesWithoutError();
   }
 
   @Test

src/test/java/com/google/devtools/common/options/processor/optiontestsources/ImmutableListTypeForAllowMultipleOption.java

@@ -0,0 +1,31 @@
+// Copyright 2017 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.common.options.processor.optiontestsources;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.common.options.Option;
+import com.google.devtools.common.options.OptionDocumentationCategory;
+import com.google.devtools.common.options.OptionEffectTag;
+import com.google.devtools.common.options.OptionsBase;
+
+/** This example options class should compile. */
+public class ImmutableListTypeForAllowMultipleOption extends OptionsBase {
+  @Option(
+      name = "option",
+      defaultValue = "null",
+      documentationCategory = OptionDocumentationCategory.UNCATEGORIZED,
+      effectTags = {OptionEffectTag.NO_OP},
+      allowMultiple = true)
+  public ImmutableList<String> badOption;
+}