Use default values when switching anyOf option

CHANGELOG.md

@@ -25,6 +25,7 @@ should change the heading of the (upcoming) version to include a major version b
 ## @rjsf/core
 
 - Updated `NumberField` to properly pass through the `errorSchema` and `id` in the onChange handler, fixing [#4382](https://github.com/rjsf-team/react-jsonschema-form/issues/4382)
+- Fix default value population when switching between options in `MultiSchemaField` [#4375](https://github.com/rjsf-team/react-jsonschema-form/pull/4375). Fixes [#4367](https://github.com/rjsf-team/react-jsonschema-form/issues/4367)
 
 ## Dev / docs / playground
 
@@ -61,7 +62,7 @@ should change the heading of the (upcoming) version to include a major version b
 
 - Fix issue 'Maximum call stack size exceeded' with playground share with large content.
 
-# 5.22.3 
+# 5.22.3
 
 ## @rjsf/utils
 
@@ -137,7 +138,7 @@ should change the heading of the (upcoming) version to include a major version b
 
 ## @rjsf/core
 
-- Updated `Form` to fix `focusOnError()` to support the ids that include dots, fixing [#4279](https://github.com/rjsf-team/react-jsonschema-form/issues/4279) 
+- Updated `Form` to fix `focusOnError()` to support the ids that include dots, fixing [#4279](https://github.com/rjsf-team/react-jsonschema-form/issues/4279)
 
 ## @rjsf/mui
 
@@ -165,7 +166,7 @@ should change the heading of the (upcoming) version to include a major version b
 
 # 5.20.0
 
-## @rjsf/core 
+## @rjsf/core
 
 - Support allowing raising errors from within a custom Widget [#2718](https://github.com/rjsf-team/react-jsonschema-form/issues/2718)
 - Updated `ArrayField`, `BooleanField` and `StringField` to call `optionsList()` with the additional `UiSchema` parameter, fixing [#4215](https://github.com/rjsf-team/react-jsonschema-form/issues/4215) and  [#4260](https://github.com/rjsf-team/react-jsonschema-form/issues/4260)
@@ -183,7 +184,7 @@ should change the heading of the (upcoming) version to include a major version b
 
 # 5.19.4
 
-## @rjsf/core 
+## @rjsf/core
 
 - Fix XSS when rendering schema validation errors [#4254](https://github.com/rjsf-team/react-jsonschema-form/issues/2718)
   - NOTE: This will have potential consequences if you are using the [translateString](https://rjsf-team.github.io/react-jsonschema-form/docs/api-reference/form-props/#translatestring) feature and are trying to render HTML. Switching to [Markdown](https://www.markdownguide.org/) will solve your problems.
@@ -200,7 +201,7 @@ should change the heading of the (upcoming) version to include a major version b
 
 ## Dev / docs / playground
 
-- Updated the `Validator` dropdown to add `AJV8 (discriminator)` which sets the AJV validator [discriminator](https://ajv.js.org/json-schema.html#discriminator) option to `true` to support testing schemas with that option in them 
+- Updated the `Validator` dropdown to add `AJV8 (discriminator)` which sets the AJV validator [discriminator](https://ajv.js.org/json-schema.html#discriminator) option to `true` to support testing schemas with that option in them
 
 # 5.19.3
 

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

@@ -123,7 +123,7 @@ class AnyOfField<T = any, S extends StrictRJSFSchema = RJSFSchema, F extends For
     const oldOption = selectedOption >= 0 ? retrievedOptions[selectedOption] : undefined;
 
     let newFormData = schemaUtils.sanitizeDataForNewSchema(newOption, oldOption, formData);
-    if (newFormData && newOption) {
+    if (newOption) {
       // Call getDefaultFormState to make sure defaults are populated on change. Pass "excludeObjectChildren"
       // so that only the root objects themselves are created without adding undefined children properties
       newFormData = schemaUtils.getDefaultFormState(newOption, newFormData, 'excludeObjectChildren') as T;

packages/core/test/anyOf.test.jsx

@@ -165,6 +165,37 @@ describe('anyOf', () => {
     );
   });
 
+  it('should assign a default value and set defaults on option change for scalar types schemas', () => {
+    const { node, onChange } = createFormComponent({
+      schema: {
+        type: 'object',
+        properties: {
+          foo: {
+            anyOf: [
+              { type: 'string', default: 'defaultfoo' },
+              { type: 'boolean', default: true },
+            ],
+          },
+        },
+      },
+    });
+    sinon.assert.calledWithMatch(onChange.lastCall, {
+      formData: { foo: 'defaultfoo' },
+    });
+
+    const $select = node.querySelector('select');
+
+    act(() => {
+      fireEvent.change($select, {
+        target: { value: $select.options[1].value },
+      });
+    });
+
+    sinon.assert.calledWithMatch(onChange.lastCall, {
+      formData: { foo: true },
+    });
+  });
+
   it('should assign a default value and set defaults on option change when using references', () => {
     const { node, onChange } = createFormComponent({
       schema: {

packages/core/test/oneOf.test.jsx

@@ -222,6 +222,37 @@ describe('oneOf', () => {
     );
   });
 
+  it('should assign a default value and set defaults on option change for scalar types schemas', () => {
+    const { node, onChange } = createFormComponent({
+      schema: {
+        type: 'object',
+        properties: {
+          foo: {
+            oneOf: [
+              { type: 'string', default: 'defaultfoo' },
+              { type: 'boolean', default: true },
+            ],
+          },
+        },
+      },
+    });
+    sinon.assert.calledWithMatch(onChange.lastCall, {
+      formData: { foo: 'defaultfoo' },
+    });
+
+    const $select = node.querySelector('select');
+
+    act(() => {
+      fireEvent.change($select, {
+        target: { value: $select.options[1].value },
+      });
+    });
+
+    sinon.assert.calledWithMatch(onChange.lastCall, {
+      formData: { foo: true },
+    });
+  });
+
   it('should render a custom widget', () => {
     const schema = {
       type: 'object',
@@ -573,6 +604,7 @@ describe('oneOf', () => {
       },
     };
     const formContext = { root: 'root-id', root_userId: 'userId-id' };
+
     function CustomSchemaField(props) {
       const { formContext, idSchema } = props;
       return (
@@ -582,6 +614,7 @@ describe('oneOf', () => {
         </>
       );
     }
+
     const { node } = createFormComponent({
       schema,
       formData: { userId: 'foobarbaz' },
@@ -1598,6 +1631,7 @@ describe('oneOf', () => {
         },
       },
     };
+
     function customValidate(formData, errors) {
       errors.userId.addError('test');
       return errors;