Make SkylarkValue instances mutable by default

Simplify the code by providing the default implementation of
`SkylarkValue$isImmutable` that always returns false. All objects are
considered mutable unless their `isImmutable` method is overridden.

This change doesn't affect the current behavior.

PiperOrigin-RevId: 161422029

9 files changed, 3 insertions, 46 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/actions/AbstractAction.java b/src/main/java/com/google/devtools/build/lib/actions/AbstractAction.java
index a7e1033a22..9399384c30 100644
--- a/src/main/java/com/google/devtools/build/lib/actions/AbstractAction.java
+++ b/src/main/java/com/google/devtools/build/lib/actions/AbstractAction.java
@@ -361,11 +361,6 @@ public abstract class AbstractAction implements Action, SkylarkValue {
   }
 
   @Override
-  public boolean isImmutable() {
-    return false;
-  }
-
-  @Override
   public void repr(SkylarkPrinter printer) {
     printer.append(prettyPrint()); // TODO(bazel-team): implement a readable representation
   }
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/AbstractConfiguredTarget.java b/src/main/java/com/google/devtools/build/lib/analysis/AbstractConfiguredTarget.java
index 0096575da0..8464ded1a9 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/AbstractConfiguredTarget.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/AbstractConfiguredTarget.java
@@ -211,11 +211,6 @@ public abstract class AbstractConfiguredTarget
   /** Implement in subclasses to get a skylark provider for a given {@code providerKey}. */
   protected abstract Object rawGetSkylarkProvider(String providerKey);
 
-  @Override
-  public boolean isImmutable() {
-    return false;
-  }
-
   // All main target classes must override this method to provide more descriptive strings.
   // Exceptions are currently EnvironmentGroupConfiguredTarget and PackageGroupConfiguredTarget.
   @Override
diff --git a/src/main/java/com/google/devtools/build/lib/packages/BuildType.java b/src/main/java/com/google/devtools/build/lib/packages/BuildType.java
index 70f6ba49ac..4d21b53525 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/BuildType.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/BuildType.java
@@ -531,11 +531,6 @@ public final class BuildType {
     }
 
     @Override
-    public boolean isImmutable() {
-      return false;
-    }
-
-    @Override
     public void repr(SkylarkPrinter printer) {
       // Convert to a lib.syntax.SelectorList to guarantee consistency with callers that serialize
       // directly on that type.
diff --git a/src/main/java/com/google/devtools/build/lib/rules/AliasConfiguredTarget.java b/src/main/java/com/google/devtools/build/lib/rules/AliasConfiguredTarget.java
index 42224f6d21..1dc878f38c 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/AliasConfiguredTarget.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/AliasConfiguredTarget.java
@@ -140,11 +140,6 @@ public final class AliasConfiguredTarget implements ConfiguredTarget, ClassObjec
   }
 
   @Override
-  public boolean isImmutable() {
-    return false;
-  }
-
-  @Override
   public void repr(SkylarkPrinter printer) {
     printer.append("<alias target " + label + " of " + actual.getLabel() + ">");
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java b/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java
index 6793119eaf..06974be42e 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/SkylarkAttr.java
@@ -442,11 +442,6 @@ public final class SkylarkAttr implements SkylarkValue {
   }
 
   @Override
-  public boolean isImmutable() {
-    return false;
-  }
-
-  @Override
   public void repr(SkylarkPrinter printer) {
     printer.append("<attr>");
   }
@@ -1667,11 +1662,6 @@ public final class SkylarkAttr implements SkylarkValue {
     }
 
     @Override
-    public boolean isImmutable() {
-      return false;
-    }
-
-    @Override
     public void repr(SkylarkPrinter printer) {
       printer.append("<attr." + name + ">");
     }
diff --git a/src/main/java/com/google/devtools/build/lib/skylarkinterface/SkylarkValue.java b/src/main/java/com/google/devtools/build/lib/skylarkinterface/SkylarkValue.java
index bf6a5c5586..6e316b7b32 100644
--- a/src/main/java/com/google/devtools/build/lib/skylarkinterface/SkylarkValue.java
+++ b/src/main/java/com/google/devtools/build/lib/skylarkinterface/SkylarkValue.java
@@ -27,7 +27,9 @@ public interface SkylarkValue {
    * <p>Immutability is deep, i.e. in order for a value to be immutable, all values it is composed
    * of must be immutable, too.
    */
-  boolean isImmutable();
+  default boolean isImmutable() {
+      return false;
+  }
 
   /**
    * Print an official representation of object x.
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/GlobList.java b/src/main/java/com/google/devtools/build/lib/syntax/GlobList.java
index 260c318f1f..a21b523422 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/GlobList.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/GlobList.java
@@ -127,11 +127,6 @@ public final class GlobList<E> extends ForwardingList<E> implements SkylarkValue
   }
 
   @Override
-  public boolean isImmutable() {
-    return false;
-  }
-
-  @Override
   public void repr(SkylarkPrinter printer) {
     printer.printList(this, false);
   }
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SelectorList.java b/src/main/java/com/google/devtools/build/lib/syntax/SelectorList.java
index c06089b417..57a2dc4e5d 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SelectorList.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SelectorList.java
@@ -155,9 +155,4 @@ public final class SelectorList implements SkylarkValue {
   public void repr(SkylarkPrinter printer) {
     printer.printList(elements, "", " + ", "", null);
   }
-
-  @Override
-  public boolean isImmutable() {
-    return false;
-  }
 }
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SelectorValue.java b/src/main/java/com/google/devtools/build/lib/syntax/SelectorValue.java
index 77210a5042..703cb2c66c 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SelectorValue.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SelectorValue.java
@@ -86,9 +86,4 @@ public final class SelectorValue implements SkylarkValue {
   public void reprLegacy(SkylarkPrinter printer) {
     printer.format("selector(%r)", dictionary);
   }
-
-  @Override
-  public boolean isImmutable() {
-    return false;
-  }
 }