cel-expr · copybara-service · Feb 13, 2025 · Feb 13, 2025
diff --git a/runtime/src/main/java/dev/cel/runtime/Activation.java b/runtime/src/main/java/dev/cel/runtime/Activation.java
@@ -50,12 +50,12 @@ public abstract class Activation implements GlobalResolver {
 
         @Override
         public @Nullable Object resolve(String name) {
-          return null;
+          return GlobalResolver.EMPTY.resolve(name);
         }
 
         @Override
         public String toString() {
-          return "{}";
+          return GlobalResolver.EMPTY.toString();
         }
       };
 

diff --git a/runtime/src/main/java/dev/cel/runtime/GlobalResolver.java b/runtime/src/main/java/dev/cel/runtime/GlobalResolver.java
@@ -23,10 +23,25 @@
  *
  * <p>CEL Library Internals. Do Not Use.
  */
+@SuppressWarnings("AndroidJdkLibsChecker") // FunctionalInterface added in 24
 @FunctionalInterface
 @Internal
 public interface GlobalResolver {
 
+  /** An empty binder which resolves everything to null. */
+  GlobalResolver EMPTY =
+      new GlobalResolver() {
+        @Override
+        public @Nullable Object resolve(String name) {
+          return null;
+        }
+
+        @Override
+        public String toString() {
+          return "{}";
+        }
+      };
+
   /** Resolves the given name to its value. Returns null if resolution fails. */
   @Nullable Object resolve(String name);
 }
diff --git a/runtime/src/main/java/dev/cel/runtime/RuntimeUnknownResolver.java b/runtime/src/main/java/dev/cel/runtime/RuntimeUnknownResolver.java
@@ -66,7 +66,7 @@ public static class Builder {
     private GlobalResolver resolver;
 
     private Builder() {
-      resolver = Activation.EMPTY;
+      resolver = GlobalResolver.EMPTY;
       attributeResolver = DEFAULT_RESOLVER;
     }