Adding feature to support const as default bug fix seeming like a regression (#4381)

Fixes #4344, #4361 and #4377
- In `@rjsf/utils`:
  - Updated the `Experimental_DefaultFormStateBehavior` type to add new optional `constAsDefaults` prop with three choices
  - Updated `getDefaultFormState()` to respond to the new `constAsDefaults` feature to limit `const` as defaults based on the `never` or `skipOneOf` choices
  - Added tests for `getDefaultFormState()` to verify the new feature
- In `@rjsf/core`:
  - Updated `SchemaField` to remove making the field readonly when const
- In `playground`:
  - Updated `Header` to add support for `constAsDefaults`
- Updated the `CHANGELOG.md` accordingly

Author: heath-freenome

CHANGELOG.md

@@ -16,6 +16,21 @@ should change the heading of the (upcoming) version to include a major version b
 
 -->
 
+# 5.23.0
+
+## @rjsf/core
+
+- Updated `SchemaField` to no longer make schema fields with const read-only by default, partially fixing [#4344](https://github.com/rjsf-team/react-jsonschema-form/issues/4344)
+
+## @rjsf/utils
+
+- Updated `Experimental_DefaultFormStateBehavior` to add a new `constAsDefaults` option
+- Updated `getDefaultFormState()` to use the new `constAsDefaults` option to control how const is used for defaulting, fixing [#4344](https://github.com/rjsf-team/react-jsonschema-form/issues/4344), [#4361](https://github.com/rjsf-team/react-jsonschema-form/issues/4361) and [#4377](https://github.com/rjsf-team/react-jsonschema-form/issues/4377)
+
+## Dev / docs / playground
+
+- Updated the playground to add a selector for the `constAsDefaults` option
+
 # 5.22.4
 
 ## @rjsf/utils

packages/core/src/components/fields/SchemaField.tsx

@@ -151,9 +151,7 @@ function SchemaFieldRender<T = any, S extends StrictRJSFSchema = RJSFSchema, F e
 
   const FieldComponent = getFieldComponent<T, S, F>(schema, uiOptions, idSchema, registry);
   const disabled = Boolean(uiOptions.disabled ?? props.disabled);
-  const readonly = Boolean(
-    uiOptions.readonly ?? (props.readonly || props.schema.const || props.schema.readOnly || schema.readOnly)
-  );
+  const readonly = Boolean(uiOptions.readonly ?? (props.readonly || props.schema.readOnly || schema.readOnly));
   const uiSchemaHideError = uiOptions.hideError;
   // Set hideError to the value provided in the uiSchema, otherwise stick with the prop to propagate to children
   const hideError = uiSchemaHideError === undefined ? props.hideError : Boolean(uiSchemaHideError);

packages/docs/docs/api-reference/form-props.md

@@ -251,6 +251,18 @@ render(
 );
 ```
 
+### constAsDefaults
+
+Optional enumerated flag controlling how const values are merged into the form data as defaults when dealing with undefined values, defaulting to `always`.
+The defaulting behavior for this flag will always be controlled by the `emptyObjectField` flag value.
+For instance, if `populateRequiredDefaults` is set and the const value is not required, it will not be set.
+
+| Flag Value  | Description                                                                                                                                                                                                                     |
+| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `always`    | A const value will always be merged into the form as a default. If there is are const values in a `oneOf` (for instance to create an enumeration with title different from the values), the first const value will be defaulted |
+| `skipOneOf` | If const is in a `oneOf` it will NOT pick the first value as a default                                                                                                                                                          |
+| `never`     | A const value will never be used as a default                                                                                                                                                                                   |
+
 ### mergeDefaultsIntoFormData
 
 Optional enumerated flag controlling how the defaults are merged into the form data when dealing with undefined values, defaulting to `useFormDataIfPresent`.

packages/playground/src/components/Header.tsx

@@ -128,6 +128,28 @@ const liveSettingsSelectSchema: RJSFSchema = {
             },
           ],
         },
+        constAsDefaults: {
+          type: 'string',
+          title: 'const as default behavior',
+          default: 'always',
+          oneOf: [
+            {
+              type: 'string',
+              title: 'A const value will always be merged into the form as a default',
+              enum: ['always'],
+            },
+            {
+              type: 'string',
+              title: 'If const is in a `oneOf` it will NOT pick the first value as a default',
+              enum: ['skipOneOf'],
+            },
+            {
+              type: 'string',
+              title: 'A const value will never be used as a default',
+              enum: ['never'],
+            },
+          ],
+        },
         emptyObjectFields: {
           type: 'string',
           title: 'Object fields default behavior',

packages/utils/src/schema/getDefaultFormState.ts

@@ -31,9 +31,10 @@ import {
 } from '../types';
 import isMultiSelect from './isMultiSelect';
 import retrieveSchema, { resolveDependencies } from './retrieveSchema';
-import isConstant from '../isConstant';
 import { JSONSchema7Object } from 'json-schema';
 
+const PRIMITIVE_TYPES = ['string', 'number', 'integer', 'boolean', 'null'];
+
 /** Enum that indicates how `schema.additionalItems` should be handled by the `getInnerSchemaForArrayItem()` function.
  */
 export enum AdditionalItemsHandling {
@@ -199,9 +200,10 @@ export function computeDefaults<T = any, S extends StrictRJSFSchema = RJSFSchema
   let defaults: T | T[] | undefined = parentDefaults;
   // If we get a new schema, then we need to recompute defaults again for the new schema found.
   let schemaToCompute: S | null = null;
+  let experimental_dfsb_to_compute = experimental_defaultFormStateBehavior;
   let updatedRecurseList = _recurseList;
 
-  if (isConstant(schema)) {
+  if (schema[CONST_KEY] && experimental_defaultFormStateBehavior?.constAsDefaults !== 'never') {
     defaults = schema.const as unknown as T;
   } else if (isObject(defaults) && isObject(schema.default)) {
     // For object defaults, only override parent defaults that are defined in
@@ -250,6 +252,15 @@ export function computeDefaults<T = any, S extends StrictRJSFSchema = RJSFSchema
       return undefined;
     }
     const discriminator = getDiscriminatorFieldFromSchema<S>(schema);
+    const { type = 'null' } = remaining;
+    if (
+      !Array.isArray(type) &&
+      PRIMITIVE_TYPES.includes(type) &&
+      experimental_dfsb_to_compute?.constAsDefaults === 'skipOneOf'
+    ) {
+      // If we are in a oneOf of a primitive type, then we want to pass constAsDefaults as 'never' for the recursion
+      experimental_dfsb_to_compute = { ...experimental_dfsb_to_compute, constAsDefaults: 'never' };
+    }
     schemaToCompute = oneOf![
       getClosestMatchingOption<T, S, F>(
         validator,
@@ -285,7 +296,7 @@ export function computeDefaults<T = any, S extends StrictRJSFSchema = RJSFSchema
       rootSchema,
       includeUndefinedValues,
       _recurseList: updatedRecurseList,
-      experimental_defaultFormStateBehavior,
+      experimental_defaultFormStateBehavior: experimental_dfsb_to_compute,
       parentDefaults: defaults as T | undefined,
       rawFormData: formData as T,
       required,
@@ -337,9 +348,12 @@ export function getObjectDefaults<T = any, S extends StrictRJSFSchema = RJSFSche
     const objectDefaults = Object.keys(retrievedSchema.properties || {}).reduce(
       (acc: GenericObjectType, key: string) => {
         const propertySchema = get(retrievedSchema, [PROPERTIES_KEY, key]);
-        // Check if the parent schema has a const property defined, then we should always return the computedDefault since it's coming from the const.
+        // Check if the parent schema has a const property defined AND we are supporting const as defaults, then we
+        // should always return the computedDefault since it's coming from the const.
         const hasParentConst = isObject(parentConst) && (parentConst as JSONSchema7Object)[key] !== undefined;
-        const hasConst = (isObject(propertySchema) && CONST_KEY in propertySchema) || hasParentConst;
+        const hasConst =
+          ((isObject(propertySchema) && CONST_KEY in propertySchema) || hasParentConst) &&
+          experimental_defaultFormStateBehavior?.constAsDefaults !== 'never';
         // Compute the defaults for this node, with the parent defaults we might
         // have from a previous run: defaults[key].
         const computedDefault = computeDefaults<T, S, F>(validator, propertySchema, {
@@ -481,8 +495,10 @@ export function getArrayDefaults<T = any, S extends StrictRJSFSchema = RJSFSchem
     }
   }
 
-  // Check if the schema has a const property defined, then we should always return the computedDefault since it's coming from the const.
-  const hasConst = isObject(schema) && CONST_KEY in schema;
+  // Check if the schema has a const property defined AND we are supporting const as defaults, then we should always
+  // return the computedDefault since it's coming from the const.
+  const hasConst =
+    isObject(schema) && CONST_KEY in schema && experimental_defaultFormStateBehavior?.constAsDefaults !== 'never';
   if (hasConst === false) {
     if (neverPopulate) {
       return defaults ?? emptyDefault;

packages/utils/src/types.ts

@@ -96,6 +96,18 @@ export type Experimental_DefaultFormStateBehavior = {
    *        default value instead
    */
   mergeDefaultsIntoFormData?: 'useFormDataIfPresent' | 'useDefaultIfFormDataUndefined';
+  /** Optional enumerated flag controlling how const values are merged into the form data as defaults when dealing with
+   * undefined values, defaulting to `always`. The defaulting behavior for this flag will always be controlled by the
+   * `emptyObjectField` flag value. For instance, if `populateRequiredDefaults` is set and the const value is not
+   * required, it will not be set.
+   * - `always`: A const value will always be merged into the form as a default. If there is are const values in a
+   *        `oneOf` (for instance to create an enumeration with title different from the values), the first const value
+   *        will be defaulted
+   * - `skipOneOf`: If const is in a `oneOf` it will NOT pick the first value as a default
+   * - `never`: A const value will never be used as a default
+   *
+   */
+  constAsDefaults?: 'always' | 'skipOneOf' | 'never';
 };
 
 /** Optional function that allows for custom merging of `allOf` schemas