Fix bytes(string) standard function to respect evaluateCanonicalTypesToNativeValues flag

PiperOrigin-RevId: 813993145

Author: l46kok

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

@@ -2107,6 +2107,23 @@ public void program_evaluateCanonicalTypesToNativeTypesDisabled_producesProtoVal
     assertThat(result).containsExactly(com.google.protobuf.NullValue.NULL_VALUE, expectedNestedMap);
   }
 
+  @Test
+  public void program_evaluateCanonicalTypesToNativeTypesDisabled_producesBytesProto()
+      throws Exception {
+    Cel cel =
+        standardCelBuilderWithMacros()
+            .addMessageTypes(TestAllTypes.getDescriptor())
+            .setContainer(CelContainer.ofName("cel.expr.conformance.proto3"))
+            .setOptions(CelOptions.current().evaluateCanonicalTypesToNativeValues(false).build())
+            .build();
+    CelAbstractSyntaxTree ast =
+        cel.compile("TestAllTypes{single_bytes: bytes('abc')}.single_bytes").getAst();
+
+    ByteString result = (ByteString) cel.createProgram(ast).eval();
+
+    assertThat(result).isEqualTo(ByteString.copyFromUtf8("abc"));
+  }
+
   @Test
   public void toBuilder_isImmutable() {
     CelBuilder celBuilder = CelFactory.standardCelBuilder();

runtime/src/main/java/dev/cel/runtime/standard/BytesFunction.java

@@ -50,8 +50,15 @@ public enum BytesOverload implements CelStandardOverload {
           }
         }),
     STRING_TO_BYTES(
-        (celOptions, runtimeEquality) ->
-            CelFunctionBinding.from("string_to_bytes", String.class, CelByteString::copyFromUtf8)),
+        (celOptions, runtimeEquality) -> {
+          if (celOptions.evaluateCanonicalTypesToNativeValues()) {
+            return CelFunctionBinding.from(
+                "string_to_bytes", String.class, CelByteString::copyFromUtf8);
+          } else {
+            return CelFunctionBinding.from(
+                "string_to_bytes", String.class, ByteString::copyFromUtf8);
+          }
+        }),
     ;
 
     private final FunctionBindingCreator bindingCreator;