From 163565be123fddc047346d121007bad6f54616e3 Mon Sep 17 00:00:00 2001
From: Sokwhan Huh <sokwhan@google.com>
Date: Sat, 28 Feb 2026 00:33:23 -0800
Subject: [PATCH] Null assignability fix for repeated and map fields

PiperOrigin-RevId: 876590274
---
 .../dev/cel/common/internal/ProtoAdapter.java | 31 ++++++++++++++++---
 .../test/resources/nullAssignability.baseline | 29 +++++++++++++++++
 .../dev/cel/testing/BaseInterpreterTest.java  | 27 ++++++++++++++++
 3 files changed, 83 insertions(+), 4 deletions(-)

diff --git a/common/src/main/java/dev/cel/common/internal/ProtoAdapter.java b/common/src/main/java/dev/cel/common/internal/ProtoAdapter.java
index b6648a5b8..c37c2a2a7 100644
--- a/common/src/main/java/dev/cel/common/internal/ProtoAdapter.java
+++ b/common/src/main/java/dev/cel/common/internal/ProtoAdapter.java
@@ -222,9 +222,7 @@ public Optional<Object> adaptValueToFieldType(
         throw new IllegalArgumentException("Unsupported field type");
       }
 
-      String typeFullName = fieldDescriptor.getMessageType().getFullName();
-      if (!WellKnownProto.ANY_VALUE.typeName().equals(typeFullName)
-          && !WellKnownProto.JSON_VALUE.typeName().equals(typeFullName)) {
+      if (!isAnyOrJsonValue(fieldDescriptor)) {
         return Optional.empty();
       }
     }
@@ -242,7 +240,11 @@ public Optional<Object> adaptValueToFieldType(
               getDefaultValueForMaybeMessage(keyDescriptor),
               valueDescriptor.getLiteType(),
               getDefaultValueForMaybeMessage(valueDescriptor));
+      boolean isValueAnyOrJson = isAnyOrJsonValue(valueDescriptor);
       for (Map.Entry entry : ((Map<?, ?>) fieldValue).entrySet()) {
+        if (!isValueAnyOrJson && entry.getValue() instanceof NullValue) {
+          continue;
+        }
         mapEntries.add(
             protoMapEntry.toBuilder()
                 .setKey(keyConverter.backwardConverter().convert(entry.getKey()))
@@ -252,15 +254,36 @@ public Optional<Object> adaptValueToFieldType(
       return Optional.of(mapEntries);
     }
     if (fieldDescriptor.isRepeated()) {
+      List<?> listValue = (List<?>) fieldValue;
+      if (listValue.contains(NullValue.NULL_VALUE)) {
+        if (!isAnyOrJsonValue(fieldDescriptor)) {
+          List<Object> filteredList = new ArrayList<>(listValue.size());
+          for (Object elem : listValue) {
+            if (!(elem instanceof NullValue)) {
+              filteredList.add(elem);
+            }
+          }
+          listValue = filteredList;
+        }
+      }
       return Optional.of(
           AdaptingTypes.adaptingList(
-              (List<?>) fieldValue, fieldToValueConverter(fieldDescriptor).reverse()));
+              listValue, fieldToValueConverter(fieldDescriptor).reverse()));
     }
 
     return Optional.of(
         fieldToValueConverter(fieldDescriptor).backwardConverter().convert(fieldValue));
   }
 
+  private boolean isAnyOrJsonValue(FieldDescriptor fieldDescriptor) {
+    String typeFullName =
+        fieldDescriptor.getJavaType() == FieldDescriptor.JavaType.MESSAGE
+            ? fieldDescriptor.getMessageType().getFullName()
+            : "";
+    return WellKnownProto.ANY_VALUE.typeName().equals(typeFullName)
+        || WellKnownProto.JSON_VALUE.typeName().equals(typeFullName);
+  }
+
   @SuppressWarnings("rawtypes")
   private BidiConverter fieldToValueConverter(FieldDescriptor fieldDescriptor) {
     switch (fieldDescriptor.getType()) {
diff --git a/runtime/src/test/resources/nullAssignability.baseline b/runtime/src/test/resources/nullAssignability.baseline
index 47b9c7a0d..b60f434ea 100644
--- a/runtime/src/test/resources/nullAssignability.baseline
+++ b/runtime/src/test/resources/nullAssignability.baseline
@@ -33,3 +33,32 @@ Source: has(TestAllTypes{single_timestamp: null}.single_timestamp)
 bindings: {}
 result:   false
 
+Source: TestAllTypes{repeated_timestamp: [timestamp(1), null]}.repeated_timestamp == [timestamp(1)]
+=====>
+bindings: {}
+result:   true
+
+Source: TestAllTypes{map_bool_timestamp: {true: null, false: timestamp(1)}}.map_bool_timestamp == {false: timestamp(1)}
+=====>
+bindings: {}
+result:   true
+
+Source: TestAllTypes{repeated_any: [1, null]}.repeated_any == [1, null]
+=====>
+bindings: {}
+result:   true
+
+Source: TestAllTypes{map_bool_any: {true: null, false: 1}}.map_bool_any == {true: null, false: 1}
+=====>
+bindings: {}
+result:   true
+
+Source: TestAllTypes{repeated_value: [google.protobuf.Value{bool_value: true}, null]}.repeated_value == [true, null]
+=====>
+bindings: {}
+result:   true
+
+Source: TestAllTypes{map_bool_value: {true: null, false: google.protobuf.Value{bool_value: true}}}.map_bool_value == {true: null, false: true}
+=====>
+bindings: {}
+result:   true
\ No newline at end of file
diff --git a/testing/src/main/java/dev/cel/testing/BaseInterpreterTest.java b/testing/src/main/java/dev/cel/testing/BaseInterpreterTest.java
index 144ada5a8..ce88f90fc 100644
--- a/testing/src/main/java/dev/cel/testing/BaseInterpreterTest.java
+++ b/testing/src/main/java/dev/cel/testing/BaseInterpreterTest.java
@@ -2145,6 +2145,33 @@ public void nullAssignability() throws Exception {
 
     source = "has(TestAllTypes{single_timestamp: null}.single_timestamp)";
     runTest();
+
+    source =
+        "TestAllTypes{repeated_timestamp: [timestamp(1), null]}.repeated_timestamp =="
+            + " [timestamp(1)]";
+    runTest();
+
+    source =
+        "TestAllTypes{map_bool_timestamp: {true: null, false: timestamp(1)}}.map_bool_timestamp =="
+            + " {false: timestamp(1)}";
+    runTest();
+
+    source = "TestAllTypes{repeated_any: [1, null]}.repeated_any == [1, null]";
+    runTest();
+
+    source =
+        "TestAllTypes{map_bool_any: {true: null, false: 1}}.map_bool_any == {true: null, false: 1}";
+    runTest();
+
+    source =
+        "TestAllTypes{repeated_value: [google.protobuf.Value{bool_value: true},"
+            + " null]}.repeated_value == [true, null]";
+    runTest();
+
+    source =
+        "TestAllTypes{map_bool_value: {true: null, false: google.protobuf.Value{bool_value:"
+            + " true}}}.map_bool_value == {true: null, false: true}";
+    runTest();
   }
 
   @Test