Make immutability explicit for things exposed to Skylark.

RELNOTES: None.
PiperOrigin-RevId: 152800780

2 files changed, 8 insertions, 6 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java b/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
index 58a37331b4..4a7c7262c2 100644
--- a/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
+++ b/src/test/java/com/google/devtools/build/lib/bazel/repository/skylark/SkylarkRepositoryContextTest.java
@@ -32,7 +32,6 @@ import com.google.devtools.build.lib.syntax.Argument.Passed;
 import com.google.devtools.build.lib.syntax.BuiltinFunction;
 import com.google.devtools.build.lib.syntax.FuncallExpression;
 import com.google.devtools.build.lib.syntax.Identifier;
-import com.google.devtools.build.lib.syntax.Runtime;
 import com.google.devtools.build.lib.syntax.Type;
 import com.google.devtools.build.lib.testutil.Scratch;
 import com.google.devtools.build.lib.vfs.Path;
@@ -124,9 +123,9 @@ public class SkylarkRepositoryContextTest {
     scratch.file("/path/bin/def").setExecutable(true);
     scratch.file("/bin/undef");
 
-    assertThat(context.which("anything")).isEqualTo(Runtime.NONE);
-    assertThat(context.which("def")).isEqualTo(Runtime.NONE);
-    assertThat(context.which("undef")).isEqualTo(Runtime.NONE);
+    assertThat(context.which("anything")).isNull();
+    assertThat(context.which("def")).isNull();
+    assertThat(context.which("undef")).isNull();
     assertThat(context.which("true").toString()).isEqualTo("/bin/true");
     assertThat(context.which("false").toString()).isEqualTo("/path/sbin/false");
   }
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java b/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
index 32932b6a73..848498b229 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/SkylarkEvaluationTest.java
@@ -26,12 +26,14 @@ import com.google.devtools.build.lib.analysis.FileConfiguredTarget;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTarget;
 import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
+import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import com.google.devtools.build.lib.packages.NativeClassObjectConstructor;
 import com.google.devtools.build.lib.packages.SkylarkClassObject;
 import com.google.devtools.build.lib.skylarkinterface.Param;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkCallable;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkModule;
 import com.google.devtools.build.lib.skylarkinterface.SkylarkSignature;
+import com.google.devtools.build.lib.skylarkinterface.SkylarkValue;
 import com.google.devtools.build.lib.syntax.SkylarkList.MutableList;
 import com.google.devtools.build.lib.testutil.TestMode;
 import org.junit.Before;
@@ -59,6 +61,7 @@ public class SkylarkEvaluationTest extends EvaluationTest {
     return new SkylarkTest();
   }
 
+  @Immutable
   static class Bad {
     Bad () {
     }
@@ -100,11 +103,11 @@ public class SkylarkEvaluationTest extends EvaluationTest {
     }
     @SuppressWarnings("unused")
     @SkylarkCallable(name = "nullfunc_failing", doc = "", allowReturnNones = false)
-    public Object nullfuncFailing(String p1, Integer p2) {
+    public SkylarkValue nullfuncFailing(String p1, Integer p2) {
       return null;
     }
     @SkylarkCallable(name = "nullfunc_working", doc = "", allowReturnNones = true)
-    public Object nullfuncWorking() {
+    public SkylarkValue nullfuncWorking() {
       return null;
     }
     @SkylarkCallable(name = "voidfunc", doc = "")