Fix JSON conversions involving FieldMask and Empty

PiperOrigin-RevId: 738109734

Author: l46kok

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

@@ -14,18 +14,24 @@
 
 package dev.cel.common;
 
+import com.google.common.base.CaseFormat;
+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;
 import com.google.protobuf.ListValue;
 import com.google.protobuf.NullValue;
 import com.google.protobuf.Struct;
 import com.google.protobuf.Timestamp;
 import com.google.protobuf.Value;
 import com.google.protobuf.util.Durations;
 import com.google.protobuf.util.Timestamps;
+import java.util.ArrayList;
 import java.util.Base64;
+import java.util.List;
 import java.util.Map;
 
 /**
@@ -113,11 +119,36 @@ public static Value adaptValueToJsonValue(Object value) {
       String duration = Durations.toString((Duration) value);
       return json.setStringValue(duration).build();
     }
+    if (value instanceof FieldMask) {
+      String fieldMaskStr = toJsonString((FieldMask) value);
+      return json.setStringValue(fieldMaskStr).build();
+    }
+    if (value instanceof Empty) {
+      // google.protobuf.Empty is just an empty json map {}
+      return json.setStructValue(Struct.getDefaultInstance()).build();
+    }
 
     throw new IllegalArgumentException(
         String.format("Value %s cannot be adapted to a JSON Value.", value));
   }
 
+  /**
+   * Joins the field mask's paths into a single string with commas. This logic is copied from
+   * Protobuf's FieldMaskUtil.java, which we cannot directly use here due to its dependency to
+   * descriptors.
+   */
+  private static String toJsonString(FieldMask fieldMask) {
+    List<String> paths = new ArrayList<>(fieldMask.getPathsCount());
+
+    for (String path : fieldMask.getPathsList()) {
+      if (!path.isEmpty()) {
+        paths.add(CaseFormat.LOWER_UNDERSCORE.to(CaseFormat.LOWER_CAMEL, path));
+      }
+    }
+
+    return Joiner.on(",").join(paths);
+  }
+
   /**
    * Adapts an iterable to a JSON list value.
    *

common/src/main/java/dev/cel/common/internal/ProtoAdapter.java

@@ -290,11 +290,6 @@ public Message adaptValueToProto(Object value, String protoTypeName) {
     }
 
     switch (wellKnownProto) {
-      // TODO: These should be converted properly to their primitive types. This is
-      // here to retain compatibility for time being.
-      case FIELD_MASK:
-      case EMPTY:
-        return (Message) value;
       case ANY_VALUE:
         if (value instanceof Message) {
           protoTypeName = ((Message) value).getDescriptorForType().getFullName();

common/src/main/java/dev/cel/common/internal/ProtoJavaQualifiedNames.java

@@ -91,7 +91,7 @@ public static String getJavaPackageName(FileDescriptor fileDescriptor) {
     FileOptions options = fileDescriptor.getFile().getOptions();
     StringBuilder javaPackageName = new StringBuilder();
     if (options.hasJavaPackage()) {
-      javaPackageName.append(fileDescriptor.getFile().getOptions().getJavaPackage());
+      javaPackageName.append(options.getJavaPackage());
     } else {
       javaPackageName
           // CEL-Internal-1

common/src/main/java/dev/cel/common/internal/ProtoLiteAdapter.java

@@ -95,8 +95,15 @@ public MessageLite adaptValueToWellKnownProto(Object value, WellKnownProto wellK
         return (Duration) value;
       case TIMESTAMP:
         return (Timestamp) value;
+      case EMPTY:
+      case FIELD_MASK:
+        // These two WKTs are typically used in context of JSON conversions, in which they are
+        // automatically unwrapped into equivalent primitive types.
+        // In other cases, just return the original message itself.
+        return (MessageLite) value;
       default:
-        throw new IllegalArgumentException("Unexpceted wellKnownProto kind: " + wellKnownProto);
+        throw new IllegalArgumentException(
+            "Unexpected wellKnownProto kind: " + wellKnownProto + " for value: " + value);
     }
   }
 

common/src/test/java/dev/cel/common/internal/ProtoAdapterTest.java

@@ -26,6 +26,8 @@
 import com.google.protobuf.BytesValue;
 import com.google.protobuf.DoubleValue;
 import com.google.protobuf.Duration;
+import com.google.protobuf.Empty;
+import com.google.protobuf.FieldMask;
 import com.google.protobuf.FloatValue;
 import com.google.protobuf.Int64Value;
 import com.google.protobuf.ListValue;
@@ -134,9 +136,13 @@ public static List<Object[]> data() {
               Timestamp.newBuilder().setSeconds(123).build(),
               Any.pack(Timestamp.newBuilder().setSeconds(123).build()),
             },
-            // Adaption support for the most current CelOptions.
             {UnsignedLong.valueOf(1L), UInt64Value.of(1L)},
             {UnsignedLong.valueOf(1L), Any.pack(UInt64Value.of(1L))},
+            {Empty.getDefaultInstance(), Empty.getDefaultInstance()},
+            {
+              FieldMask.newBuilder().addPaths("foo").build(),
+              FieldMask.newBuilder().addPaths("foo").build()
+            }
           });
     }
 

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

@@ -91,10 +91,6 @@ _TESTS_TO_SKIP = [
     "timestamps/timestamp_arithmetic/add_time_to_duration_nanos_negative",
 
     # Skip until fixed.
-    "wrappers/field_mask/to_json",
-    "wrappers/empty/to_json",
-    "wrappers/duration/to_json",
-    "wrappers/timestamp/to_json",
     "fields/qualified_identifier_resolution/map_value_repeat_key_heterogeneous",
     # TODO: Add strings.format and strings.quote.
     "string_ext/quote",