cel-expr · copybara-service · May 20, 2025 · May 20, 2025
diff --git a/common/src/main/java/dev/cel/common/internal/BUILD.bazel b/common/src/main/java/dev/cel/common/internal/BUILD.bazel
@@ -314,6 +314,7 @@ java_library(
    deps = [
        "//protobuf:cel_lite_descriptor",
        "@maven//:com_google_errorprone_error_prone_annotations",
+        "@maven_android//:com_google_protobuf_protobuf_javalite",
    ],
 )

@@ -325,6 +326,7 @@ cel_android_library(
    deps = [
        "//protobuf:cel_lite_descriptor",
        "@maven//:com_google_errorprone_error_prone_annotations",
+        "@maven_android//:com_google_protobuf_protobuf_javalite",
    ],
 )


diff --git a/common/src/main/java/dev/cel/common/internal/CelLiteDescriptorPool.java b/common/src/main/java/dev/cel/common/internal/CelLiteDescriptorPool.java
@@ -15,6 +15,7 @@
 package dev.cel.common.internal;

 import com.google.errorprone.annotations.Immutable;
+import com.google.protobuf.MessageLite;
 import dev.cel.protobuf.CelLiteDescriptor.MessageLiteDescriptor;
 import java.util.Optional;

@@ -25,5 +26,7 @@
 public interface CelLiteDescriptorPool {
  Optional<MessageLiteDescriptor> findDescriptor(String protoTypeName);

+  Optional<MessageLiteDescriptor> findDescriptor(MessageLite messageLite);
+
  MessageLiteDescriptor getDescriptorOrThrow(String protoTypeName);
 }
diff --git a/common/src/main/java/dev/cel/common/internal/DefaultLiteDescriptorPool.java b/common/src/main/java/dev/cel/common/internal/DefaultLiteDescriptorPool.java
@@ -50,6 +50,7 @@
 @Internal
 public final class DefaultLiteDescriptorPool implements CelLiteDescriptorPool {
  private final ImmutableMap<String, MessageLiteDescriptor> protoFqnToMessageInfo;
+  private final ImmutableMap<Class<?>, MessageLiteDescriptor> classToMessageInfo;

  public static DefaultLiteDescriptorPool newInstance(CelLiteDescriptor... descriptors) {
    return newInstance(ImmutableSet.copyOf(descriptors));
@@ -59,6 +60,11 @@ public static DefaultLiteDescriptorPool newInstance(ImmutableSet<CelLiteDescript
    return new DefaultLiteDescriptorPool(descriptors);
  }

+  @Override
+  public Optional<MessageLiteDescriptor> findDescriptor(MessageLite messageLite) {
+    return Optional.ofNullable(classToMessageInfo.get(messageLite.getClass()));
+  }
+
  @Override
  public Optional<MessageLiteDescriptor> findDescriptor(String protoTypeName) {
    return Optional.ofNullable(protoFqnToMessageInfo.get(protoTypeName));
@@ -292,15 +298,28 @@ private static FieldLiteDescriptor newPrimitiveFieldDescriptor(

  private DefaultLiteDescriptorPool(ImmutableSet<CelLiteDescriptor> descriptors) {
    ImmutableMap.Builder<String, MessageLiteDescriptor> protoFqnMapBuilder = ImmutableMap.builder();
+    ImmutableMap.Builder<Class<?>, MessageLiteDescriptor> classMapBuilder = ImmutableMap.builder();
    for (WellKnownProto wellKnownProto : WellKnownProto.values()) {
      MessageLiteDescriptor wktMessageInfo = newMessageInfo(wellKnownProto);
      protoFqnMapBuilder.put(wellKnownProto.typeName(), wktMessageInfo);
+      classMapBuilder.put(wellKnownProto.messageClass(), wktMessageInfo);
    }

    for (CelLiteDescriptor descriptor : descriptors) {
      protoFqnMapBuilder.putAll(descriptor.getProtoTypeNamesToDescriptors());
+
+      for (MessageLiteDescriptor messageLiteDescriptor :
+          descriptor.getProtoTypeNamesToDescriptors().values()) {
+        // Note: message builder is null for proto maps.
+        Optional.ofNullable(messageLiteDescriptor.newMessageBuilder())
+            .ifPresent(
+                builder ->
+                    classMapBuilder.put(
+                        builder.getDefaultInstanceForType().getClass(), messageLiteDescriptor));
+      }
    }

    this.protoFqnToMessageInfo = protoFqnMapBuilder.buildOrThrow();
+    this.classToMessageInfo = classMapBuilder.buildOrThrow();
  }
 }
diff --git a/common/src/main/java/dev/cel/common/values/ProtoLiteCelValueConverter.java b/common/src/main/java/dev/cel/common/values/ProtoLiteCelValueConverter.java
@@ -44,6 +44,7 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.NoSuchElementException;
 import java.util.TreeMap;

 /**
@@ -360,7 +361,13 @@ public CelValue fromProtoMessageToCelValue(String protoTypeName, MessageLite msg
    checkNotNull(msg);
    checkNotNull(protoTypeName);

-    MessageLiteDescriptor descriptor = descriptorPool.getDescriptorOrThrow(protoTypeName);
+    MessageLiteDescriptor descriptor =
+        descriptorPool
+            .findDescriptor(msg)
+            .orElseThrow(
+                () ->
+                    new NoSuchElementException(
+                        "Could not find a descriptor for: " + protoTypeName));
    WellKnownProto wellKnownProto =
        WellKnownProto.getByTypeName(descriptor.getProtoTypeName()).orElse(null);


diff --git a/runtime/src/test/java/dev/cel/runtime/CelLiteRuntimeTest.java b/runtime/src/test/java/dev/cel/runtime/CelLiteRuntimeTest.java
@@ -633,4 +633,31 @@ public void eval_withLateBoundFunction() throws Exception {

    assertThat(result).isEqualTo("hello world");
  }
+
+  @Test
+  public void eval_dynFunctionReturnsProto() throws Exception {
+    CelCompiler celCompiler =
+        CelCompilerFactory.standardCelCompilerBuilder()
+            .addFunctionDeclarations(
+                CelFunctionDecl.newFunctionDeclaration(
+                    "func", CelOverloadDecl.newGlobalOverload("func_identity", SimpleType.DYN)))
+            .build();
+    CelLiteRuntime celRuntime =
+        CelLiteRuntimeFactory.newLiteRuntimeBuilder()
+            .setValueProvider(
+                ProtoMessageLiteValueProvider.newInstance(
+                    TestAllTypesCelDescriptor.getDescriptor()))
+            .addFunctionBindings(
+                CelFunctionBinding.from(
+                    "func_identity",
+                    ImmutableList.of(),
+                    unused -> TestAllTypes.getDefaultInstance()))
+            .build();
+
+    CelAbstractSyntaxTree ast = celCompiler.compile("func()").getAst();
+
+    TestAllTypes result = (TestAllTypes) celRuntime.createProgram(ast).eval();
+
+    assertThat(result).isEqualToDefaultInstance();
+  }
 }