Evaluate CEL's null and bytes to their native equivalent types

bundle/src/test/java/dev/cel/bundle/BUILD.bazel

@@ -41,6 +41,8 @@ java_library(
         "//common/types:cel_proto_types",
         "//common/types:message_type_provider",
         "//common/types:type_providers",
+        "//common/values",
+        "//common/values:cel_byte_string",
         "//compiler",
         "//compiler:compiler_builder",
         "//extensions",
@@ -64,7 +66,6 @@ java_library(
         "@maven//:com_google_truth_extensions_truth_proto_extension",
         "@maven//:junit_junit",
         "@maven//:org_jspecify_jspecify",
-        "@maven_android//:com_google_protobuf_protobuf_javalite",
     ],
 )
 

bundle/src/test/java/dev/cel/bundle/CelImplTest.java

@@ -48,7 +48,6 @@
 import com.google.protobuf.Empty;
 import com.google.protobuf.FieldMask;
 import com.google.protobuf.Message;
-import com.google.protobuf.NullValue;
 import com.google.protobuf.Struct;
 import com.google.protobuf.TextFormat;
 import com.google.protobuf.Timestamp;
@@ -86,6 +85,8 @@
 import dev.cel.common.types.ProtoMessageTypeProvider;
 import dev.cel.common.types.SimpleType;
 import dev.cel.common.types.StructTypeReference;
+import dev.cel.common.values.CelByteString;
+import dev.cel.common.values.NullValue;
 import dev.cel.compiler.CelCompiler;
 import dev.cel.compiler.CelCompilerFactory;
 import dev.cel.compiler.CelCompilerImpl;
@@ -108,6 +109,7 @@
 import dev.cel.runtime.UnknownContext;
 import dev.cel.testing.testdata.proto3.StandaloneGlobalEnum;
 import java.util.ArrayList;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
@@ -1019,7 +1021,10 @@ public void program_enumTypeReferenceResolution(boolean resolveTypeDependencies)
     Cel cel =
         standardCelBuilderWithMacros()
             .setOptions(
-                CelOptions.current().resolveTypeDependencies(resolveTypeDependencies).build())
+                CelOptions.current()
+                    .evaluateCanonicalTypesToNativeValues(true)
+                    .resolveTypeDependencies(resolveTypeDependencies)
+                    .build())
             .addMessageTypes(Struct.getDescriptor())
             .setResultType(StructTypeReference.create("google.protobuf.NullValue"))
             .setContainer(CelContainer.ofName("google.protobuf"))
@@ -1037,7 +1042,11 @@ public void program_enumTypeReferenceResolution(boolean resolveTypeDependencies)
   public void program_enumTypeTransitiveResolution() throws Exception {
     Cel cel =
         standardCelBuilderWithMacros()
-            .setOptions(CelOptions.current().resolveTypeDependencies(true).build())
+            .setOptions(
+                CelOptions.current()
+                    .evaluateCanonicalTypesToNativeValues(true)
+                    .resolveTypeDependencies(true)
+                    .build())
             .addMessageTypes(Proto2ExtensionScopedMessage.getDescriptor())
             .setResultType(StructTypeReference.create("google.protobuf.NullValue"))
             .setContainer(CelContainer.ofName("google.protobuf"))
@@ -1626,7 +1635,11 @@ public void programAdvanceEvaluation_indexOnUnknownContainer() throws Exception
   public void programAdvanceEvaluation_unsupportedIndexIgnored() throws Exception {
     Cel cel =
         standardCelBuilderWithMacros()
-            .setOptions(CelOptions.current().enableUnknownTracking(true).build())
+            .setOptions(
+                CelOptions.current()
+                    .evaluateCanonicalTypesToNativeValues(true)
+                    .enableUnknownTracking(true)
+                    .build())
             .addVar("unk", MapType.create(SimpleType.STRING, SimpleType.BOOL))
             .setContainer(CelContainer.ofName(""))
             .addFunctionBindings()
@@ -1654,7 +1667,7 @@ public void programAdvanceEvaluation_unsupportedIndexIgnored() throws Exception
                 UnknownContext.create(
                     fromMap(
                         ImmutableMap.of(
-                            "unk", ImmutableMap.of(ByteString.copyFromUtf8("a"), false))),
+                            "unk", ImmutableMap.of(CelByteString.copyFromUtf8("a"), false))),
                     ImmutableList.of())))
         .isEqualTo(false);
   }
@@ -2077,6 +2090,23 @@ public void program_regexProgramSizeExceedsLimit_throws() throws Exception {
     assertThat(e.getErrorCode()).isEqualTo(CelErrorCode.INVALID_ARGUMENT);
   }
 
+  @Test
+  @SuppressWarnings("unchecked") // test only
+  public void program_evaluateCanonicalTypesToNativeTypesDisabled_producesProtoValues()
+      throws Exception {
+    Cel cel =
+        standardCelBuilderWithMacros()
+            .setOptions(CelOptions.current().evaluateCanonicalTypesToNativeValues(false).build())
+            .build();
+    CelAbstractSyntaxTree ast = cel.compile("[null, {b'abc': null}]").getAst();
+    Map<ByteString, Object> expectedNestedMap = new LinkedHashMap<>();
+    expectedNestedMap.put(ByteString.copyFromUtf8("abc"), com.google.protobuf.NullValue.NULL_VALUE);
+
+    List<Object> result = (List<Object>) cel.createProgram(ast).eval();
+
+    assertThat(result).containsExactly(com.google.protobuf.NullValue.NULL_VALUE, expectedNestedMap);
+  }
+
   @Test
   public void toBuilder_isImmutable() {
     CelBuilder celBuilder = CelFactory.standardCelBuilder();

common/src/main/java/dev/cel/common/BUILD.bazel

@@ -206,6 +206,8 @@ java_library(
     ],
     deps = [
         "//common/internal:proto_time_utils",
+        "//common/values",
+        "//common/values:cel_byte_string",
         "@maven//:com_google_errorprone_error_prone_annotations",
         "@maven//:com_google_guava_guava",
         "@maven//:com_google_protobuf_protobuf_java",

common/src/main/java/dev/cel/common/CelOptions.java

@@ -109,6 +109,8 @@ public enum ProtoUnsetFieldOptions {
 
   public abstract int comprehensionMaxIterations();
 
+  public abstract boolean evaluateCanonicalTypesToNativeValues();
+
   public abstract boolean unwrapWellKnownTypesOnFunctionDispatch();
 
   public abstract ProtoUnsetFieldOptions fromProtoUnsetFieldOption();
@@ -150,6 +152,7 @@ public static Builder newBuilder() {
         .enableNamespacedDeclarations(true)
         // Evaluation options
         .disableCelStandardEquality(true)
+        .evaluateCanonicalTypesToNativeValues(false)
         .enableShortCircuiting(true)
         .enableRegexPartialMatch(false)
         .enableUnsignedComparisonAndArithmeticIsUnsigned(false)
@@ -450,6 +453,19 @@ public abstract static class Builder {
      */
     public abstract Builder comprehensionMaxIterations(int value);
 
+    /**
+     * If set, canonical CEL types such as bytes and CEL null will return their native value
+     * equivalents instead of protobuf based values. Specifically:
+     *
+     * <ul>
+     *   <li>Bytes: {@code dev.cel.common.values.CelByteString} instead of {@code
+     *       com.google.protobuf.ByteString}.
+     *   <li>CEL null: {@code dev.cel.common.values.NullValue} instead of {@code
+     *       com.google.protobuf.NullValue}.
+     * </ul>
+     */
+    public abstract Builder evaluateCanonicalTypesToNativeValues(boolean value);
+
     /**
      * If disabled, CEL runtime will no longer adapt the function dispatch results for protobuf's
      * well known types to other types. This option is enabled by default.

common/src/main/java/dev/cel/common/CelProtoJsonAdapter.java

@@ -18,7 +18,6 @@
 import com.google.common.base.Joiner;
 import com.google.common.primitives.UnsignedLong;
 import com.google.errorprone.annotations.Immutable;
-import com.google.protobuf.ByteString;
 import com.google.protobuf.Duration;
 import com.google.protobuf.Empty;
 import com.google.protobuf.FieldMask;
@@ -28,6 +27,7 @@
 import com.google.protobuf.Timestamp;
 import com.google.protobuf.Value;
 import dev.cel.common.internal.ProtoTimeUtils;
+import dev.cel.common.values.CelByteString;
 import java.util.ArrayList;
 import java.util.Base64;
 import java.util.List;
@@ -71,7 +71,7 @@ public static <K extends String, V> Struct adaptToJsonStructValue(Map<K, V> map)
   @SuppressWarnings("unchecked")
   public static Value adaptValueToJsonValue(Object value) {
     Value.Builder json = Value.newBuilder();
-    if (value == null || value instanceof NullValue) {
+    if (value == null || value instanceof dev.cel.common.values.NullValue) {
       return json.setNullValue(NullValue.NULL_VALUE).build();
     }
     if (value instanceof Boolean) {
@@ -93,9 +93,9 @@ public static Value adaptValueToJsonValue(Object value) {
     if (value instanceof Float || value instanceof Double) {
       return json.setNumberValue(((Number) value).doubleValue()).build();
     }
-    if (value instanceof ByteString) {
+    if (value instanceof CelByteString) {
       return json.setStringValue(
-              Base64.getEncoder().encodeToString(((ByteString) value).toByteArray()))
+              Base64.getEncoder().encodeToString(((CelByteString) value).toByteArray()))
           .build();
     }
     if (value instanceof String) {

common/src/main/java/dev/cel/common/ast/BUILD.bazel

@@ -49,6 +49,8 @@ java_library(
     deps = [
         "//:auto_value",
         "//common/annotations",
+        "//common/values",
+        "//common/values:cel_byte_string",
         "@maven//:com_google_errorprone_error_prone_annotations",
         "@maven//:com_google_guava_guava",
         "@maven//:com_google_protobuf_protobuf_java",
@@ -62,9 +64,12 @@ java_library(
     ],
     deps = [
         ":ast",
+        "//common/values",
+        "//common/values:cel_byte_string",
         "@cel_spec//proto/cel/expr:checked_java_proto",
         "@cel_spec//proto/cel/expr:syntax_java_proto",
         "@maven//:com_google_guava_guava",
+        "@maven//:com_google_protobuf_protobuf_java",
     ],
 )
 
@@ -75,9 +80,12 @@ cel_android_library(
     ],
     deps = [
         ":ast_android",
+        "//common/values:cel_byte_string",
+        "//common/values:values_android",
         "@cel_spec//proto/cel/expr:checked_java_proto_lite",
         "@cel_spec//proto/cel/expr:syntax_java_proto_lite",
         "@maven_android//:com_google_guava_guava",
+        "@maven_android//:com_google_protobuf_protobuf_javalite",
     ],
 )
 
@@ -88,8 +96,11 @@ java_library(
     ],
     deps = [
         ":ast",
+        "//common/values",
+        "//common/values:cel_byte_string",
         "@com_google_googleapis//google/api/expr/v1alpha1:expr_java_proto",
         "@maven//:com_google_guava_guava",
+        "@maven//:com_google_protobuf_protobuf_java",
     ],
 )
 
@@ -112,8 +123,8 @@ java_library(
     deps = [
         ":ast",
         "//common/annotations",
+        "//common/values:cel_byte_string",
         "@maven//:com_google_guava_guava",
-        "@maven//:com_google_protobuf_protobuf_java",
     ],
 )
 
@@ -136,6 +147,8 @@ cel_android_library(
     deps = [
         "//:auto_value",
         "//common/annotations",
+        "//common/values:cel_byte_string",
+        "//common/values:values_android",
         "@maven//:com_google_errorprone_error_prone_annotations",
         "@maven_android//:com_google_guava_guava",
         "@maven_android//:com_google_protobuf_protobuf_javalite",

common/src/main/java/dev/cel/common/ast/CelConstant.java

@@ -19,11 +19,13 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.common.primitives.UnsignedLong;
 import com.google.errorprone.annotations.Immutable;
+import com.google.errorprone.annotations.InlineMe;
 import com.google.protobuf.ByteString;
 import com.google.protobuf.Duration;
-import com.google.protobuf.NullValue;
 import com.google.protobuf.Timestamp;
 import dev.cel.common.annotations.Internal;
+import dev.cel.common.values.CelByteString;
+import dev.cel.common.values.NullValue;
 
 /**
  * Represents a primitive literal.
@@ -42,7 +44,7 @@ public abstract class CelConstant {
           UnsignedLong.class,
           Double.class,
           String.class,
-          ByteString.class);
+          CelByteString.class);
 
   /** Represents the type of the Constant */
   public enum Kind {
@@ -92,7 +94,7 @@ public abstract static class CelConstantNotSet {}
 
   public abstract String stringValue();
 
-  public abstract ByteString bytesValue();
+  public abstract CelByteString bytesValue();
 
   /**
    * @deprecated Do not use. Timestamp is no longer built-in CEL type.
@@ -134,10 +136,46 @@ public static CelConstant ofValue(String value) {
     return AutoOneOf_CelConstant.stringValue(value);
   }
 
-  public static CelConstant ofValue(ByteString value) {
+  public static CelConstant ofValue(CelByteString value) {
     return AutoOneOf_CelConstant.bytesValue(value);
   }
 
+  /**
+   * @deprecated Use native type equivalent {@link #ofValue(NullValue)} instead.
+   */
+  @InlineMe(
+      replacement = "CelConstant.ofValue(NullValue.NULL_VALUE)",
+      imports = {"dev.cel.common.ast.CelConstant", "dev.cel.common.values.NullValue"})
+  @Deprecated
+  public static CelConstant ofValue(com.google.protobuf.NullValue unused) {
+    return ofValue(NullValue.NULL_VALUE);
+  }
+
+  /**
+   * @deprecated Use native type equivalent {@link #ofValue(CelByteString)} instead.
+   */
+  @Deprecated
+  public static CelConstant ofValue(ByteString value) {
+    CelByteString celByteString = CelByteString.of(value.toByteArray());
+    return ofValue(celByteString);
+  }
+
+  /**
+   * @deprecated Do not use. Duration is no longer built-in CEL type.
+   */
+  @Deprecated
+  public static CelConstant ofValue(Duration value) {
+    return AutoOneOf_CelConstant.durationValue(value);
+  }
+
+  /**
+   * @deprecated Do not use. Timestamp is no longer built-in CEL type.
+   */
+  @Deprecated
+  public static CelConstant ofValue(Timestamp value) {
+    return AutoOneOf_CelConstant.timestampValue(value);
+  }
+
   /** Checks whether the provided Java object is a valid CelConstant value. */
   public static boolean isConstantValue(Object value) {
     return CONSTANT_CLASSES.contains(value.getClass());
@@ -163,26 +201,10 @@ public static CelConstant ofObjectValue(Object value) {
       return ofValue((double) value);
     } else if (value instanceof String) {
       return ofValue((String) value);
-    } else if (value instanceof ByteString) {
-      return ofValue((ByteString) value);
+    } else if (value instanceof CelByteString) {
+      return ofValue((CelByteString) value);
     }
 
     throw new IllegalArgumentException("Value is not a CelConstant: " + value);
   }
-
-  /**
-   * @deprecated Do not use. Duration is no longer built-in CEL type.
-   */
-  @Deprecated
-  public static CelConstant ofValue(Duration value) {
-    return AutoOneOf_CelConstant.durationValue(value);
-  }
-
-  /**
-   * @deprecated Do not use. Timestamp is no longer built-in CEL type.
-   */
-  @Deprecated
-  public static CelConstant ofValue(Timestamp value) {
-    return AutoOneOf_CelConstant.timestampValue(value);
-  }
 }