Better error output with incorrect annotations

Author: kevmoo

json_serializable/lib/src/json_key_utils.dart

@@ -41,6 +41,7 @@ KeyConfig _from(FieldElement element, ClassConfig classAnnotation) {
   /// an [InvalidGenerationSourceError] using [typeInformation] to describe
   /// the unsupported type.
   Object? literalForObject(
+    String fieldName,
     DartObject dartObject,
     Iterable<String> typeInformation,
   ) {
@@ -65,7 +66,9 @@ KeyConfig _from(FieldElement element, ClassConfig classAnnotation) {
     if (badType != null) {
       badType = typeInformation.followedBy([badType]).join(' > ');
       throwUnsupported(
-          element, '`defaultValue` is `$badType`, it must be a literal.');
+        element,
+        '`$fieldName` is `$badType`, it must be a literal.',
+      );
     }
 
     if (reader.isDouble || reader.isInt || reader.isString || reader.isBool) {
@@ -75,7 +78,7 @@ KeyConfig _from(FieldElement element, ClassConfig classAnnotation) {
     if (reader.isList) {
       return [
         for (var e in reader.listValue)
-          literalForObject(e, [
+          literalForObject(fieldName, e, [
             ...typeInformation,
             'List',
           ])
@@ -85,7 +88,7 @@ KeyConfig _from(FieldElement element, ClassConfig classAnnotation) {
     if (reader.isSet) {
       return {
         for (var e in reader.setValue)
-          literalForObject(e, [
+          literalForObject(fieldName, e, [
             ...typeInformation,
             'Set',
           ])
@@ -99,8 +102,8 @@ KeyConfig _from(FieldElement element, ClassConfig classAnnotation) {
       ];
       return reader.mapValue.map(
         (k, v) => MapEntry(
-          literalForObject(k!, mapTypeInformation),
-          literalForObject(v!, mapTypeInformation),
+          literalForObject(fieldName, k!, mapTypeInformation),
+          literalForObject(fieldName, v!, mapTypeInformation),
         ),
       );
     }
@@ -163,7 +166,7 @@ KeyConfig _from(FieldElement element, ClassConfig classAnnotation) {
     } else {
       final defaultValueLiteral = annotationValue.isNull
           ? null
-          : literalForObject(annotationValue.objectValue, []);
+          : literalForObject(fieldName, annotationValue.objectValue, []);
       if (defaultValueLiteral == null) {
         return null;
       }

json_serializable/lib/src/utils.dart

@@ -28,8 +28,9 @@ bool hasJsonKeyAnnotation(FieldElement element) =>
 
 Never throwUnsupported(FieldElement element, String message) =>
     throw InvalidGenerationSourceError(
-        'Error with `@JsonKey` on `${element.name}`. $message',
-        element: element);
+      'Error with `@JsonKey` on the `${element.name}` field. $message',
+      element: element,
+    );
 
 FieldRename? _fromDartObject(ConstantReader reader) => reader.isNull
     ? null

json_serializable/test/src/_json_serializable_test_input.dart

@@ -330,7 +330,7 @@ class PrivateFieldCtorClass {
 }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. '
+  'Error with `@JsonKey` on the `field` field. '
   'Cannot set both `disallowNullValue` and `includeIfNull` to `true`. '
   'This leads to incompatible `toJson` and `fromJson` behavior.',
   element: 'field',

json_serializable/test/src/default_value_input.dart

@@ -5,7 +5,7 @@
 part of '_json_serializable_test_input.dart';
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. '
+  'Error with `@JsonKey` on the `field` field. '
   '`defaultValue` is `Symbol`, it must be a literal.',
   element: 'field',
 )
@@ -20,7 +20,7 @@ class DefaultWithSymbol {
 int _function() => 42;
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. '
+  'Error with `@JsonKey` on the `field` field. '
   '`defaultValue` is `Function`, it must be a literal.',
   element: 'field',
 )
@@ -33,7 +33,7 @@ class DefaultWithFunction {
 }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. '
+  'Error with `@JsonKey` on the `field` field. '
   '`defaultValue` is `Type`, it must be a literal.',
   element: 'field',
 )
@@ -46,7 +46,7 @@ class DefaultWithType {
 }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. '
+  'Error with `@JsonKey` on the `field` field. '
   '`defaultValue` is `Duration`, it must be a literal.',
   element: 'field',
 )
@@ -61,7 +61,7 @@ class DefaultWithConstObject {
 enum Enum { value }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. '
+  'Error with `@JsonKey` on the `field` field. '
   '`defaultValue` is `List > Enum`, it must be a literal.',
   element: 'field',
 )

json_serializable/test/src/to_from_json_test_input.dart

@@ -15,8 +15,8 @@ Object _toObject(Object input) => throw UnimplementedError();
 String _toStringFromObject(Object? input) => throw UnimplementedError();
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. The `fromJson` function `_toInt` '
-  'return type `int` is not compatible with field type `String`.',
+  'Error with `@JsonKey` on the `field` field. The `fromJson` function '
+  '`_toInt` return type `int` is not compatible with field type `String`.',
   element: 'field',
 )
 @JsonSerializable()
@@ -26,7 +26,7 @@ class BadFromFuncReturnType {
 }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. The `fromJson` function '
+  'Error with `@JsonKey` on the `field` field. The `fromJson` function '
   '`_twoArgFunction` must have one positional parameter.',
   element: 'field',
 )
@@ -59,7 +59,7 @@ class ValidToFromFuncClassStatic {
 }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. The `toJson` function `_toInt` '
+  'Error with `@JsonKey` on the `field` field. The `toJson` function `_toInt` '
   'argument type `bool` is not compatible with field type `String`.',
   element: 'field',
 )
@@ -70,8 +70,9 @@ class BadToFuncReturnType {
 }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `values`. The `fromJson` function `_fromList` '
-  'return type `List<int>?` is not compatible with field type `List<int>`.',
+  'Error with `@JsonKey` on the `values` field. The `fromJson` function '
+  '`_fromList` return type `List<int>?` is not compatible with field type '
+  '`List<int>`.',
   element: 'values',
 )
 @JsonSerializable()
@@ -127,7 +128,7 @@ List<List>? _toList(List<int>? pairs) =>
     pairs?.map((it) => [it]).toList(growable: false);
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. The `toJson` function '
+  'Error with `@JsonKey` on the `field` field. The `toJson` function '
   '`_twoArgFunction` must have one positional parameter.',
   element: 'field',
 )
@@ -248,7 +249,7 @@ class FromNullableDynamicCollection {
 String _noArgs() => throw UnimplementedError();
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. The `fromJson` function '
+  'Error with `@JsonKey` on the `field` field. The `fromJson` function '
   '`_noArgs` must have one positional parameter.',
   element: 'field',
 )
@@ -261,7 +262,7 @@ class BadNoArgs {
 String? _twoArgs(a, b) => null;
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. The `fromJson` function '
+  'Error with `@JsonKey` on the `field` field. The `fromJson` function '
   '`_twoArgs` must have one positional parameter.',
   element: 'field',
 )
@@ -274,7 +275,7 @@ class BadTwoRequiredPositional {
 String? _oneNamed({a}) => null;
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `field`. The `fromJson` function '
+  'Error with `@JsonKey` on the `field` field. The `fromJson` function '
   '`_oneNamed` must have one positional parameter.',
   element: 'field',
 )

json_serializable/test/src/unknown_enum_value_test_input.dart

@@ -32,7 +32,7 @@ class UnknownEnumValue {
 enum UnknownEnumValueItems { v0, v1, v2, vUnknown, vNull }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `value`. `unknownEnumValue` has type '
+  'Error with `@JsonKey` on the `value` field. `unknownEnumValue` has type '
   '`int`, but the provided unknownEnumValue is of type '
   '`WrongEnumType`.',
 )
@@ -43,7 +43,7 @@ class UnknownEnumValueListWrongType {
 }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `value`. `unknownEnumValue` has type '
+  'Error with `@JsonKey` on the `value` field. `unknownEnumValue` has type '
   '`UnknownEnumValueItems`, but the provided unknownEnumValue is of type '
   '`WrongEnumType`.',
 )
@@ -56,7 +56,7 @@ class UnknownEnumValueListWrongEnumType {
 enum WrongEnumType { otherValue }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `value`. `unknownEnumValue` has type '
+  'Error with `@JsonKey` on the `value` field. `unknownEnumValue` has type '
   '`UnknownEnumValueItems`, but the provided unknownEnumValue is of type '
   '`WrongEnumType`.',
 )
@@ -67,7 +67,7 @@ class UnknownEnumValueWrongEnumType {
 }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `value`. The value provided '
+  'Error with `@JsonKey` on the `value` field. The value provided '
   'for `unknownEnumValue` must be a matching enum.',
 )
 @JsonSerializable()
@@ -77,8 +77,9 @@ class UnknownEnumValueNotEnumValue {
 }
 
 @ShouldThrow(
-  'Error with `@JsonKey` on `value`. `unknownEnumValue` can only be set on '
-  'fields of type enum or on Iterable, List, or Set instances of an enum type.',
+  'Error with `@JsonKey` on the `value` field. `unknownEnumValue` can only be '
+  'set on fields of type enum or on Iterable, List, or Set instances of an '
+  'enum type.',
 )
 @JsonSerializable()
 class UnknownEnumValueNotEnumField {