Bug: Default value not being prefilled when object with if/then is nested inside another object.

CHANGELOG.md

@@ -20,6 +20,7 @@ should change the heading of the (upcoming) version to include a major version b
 
 ## @rjsf/utils
 
+- Fixed issue with default value not being prefilled when object with if/then is nested inside another object, fixing [#4222](https://github.com/rjsf-team/react-jsonschema-form/issues/4222)
 - Fixed issue with schema array with nested dependent fixed-length, fixing [#3754](https://github.com/rjsf-team/react-jsonschema-form/issues/3754)
 
 

packages/utils/src/schema/getDefaultFormState.ts

@@ -8,6 +8,7 @@ import {
   CONST_KEY,
   DEFAULT_KEY,
   DEPENDENCIES_KEY,
+  IF_KEY,
   ONE_OF_KEY,
   PROPERTIES_KEY,
   REF_KEY,
@@ -478,12 +479,16 @@ export function getObjectDefaults<T = any, S extends StrictRJSFSchema = RJSFSche
   {
     const formData: T = (isObject(rawFormData) ? rawFormData : {}) as T;
     const schema: S = rawSchema;
-    // This is a custom addition that fixes this issue:
-    // https://github.com/rjsf-team/react-jsonschema-form/issues/3832
-    const retrievedSchema =
-      experimental_defaultFormStateBehavior?.allOf === 'populateDefaults' && ALL_OF_KEY in schema
-        ? retrieveSchema<T, S, F>(validator, schema, rootSchema, formData, experimental_customMergeAllOf)
-        : schema;
+    // Retrieve the schema:
+    // - If schema contains `allOf` AND `experimental_defaultFormStateBehavior.allOf` is set to `populateDefaults`
+    // - OR if schema contains an 'if' AND `emptyObjectFields` is not set to `skipEmptyDefaults`
+    // This ensures we compute defaults correctly for schemas with these keywords.
+    const shouldRetrieveSchema =
+      (experimental_defaultFormStateBehavior?.allOf === 'populateDefaults' && ALL_OF_KEY in schema) ||
+      (experimental_defaultFormStateBehavior?.emptyObjectFields !== 'skipEmptyDefaults' && IF_KEY in schema);
+    const retrievedSchema = shouldRetrieveSchema
+      ? retrieveSchema<T, S, F>(validator, schema, rootSchema, formData, experimental_customMergeAllOf)
+      : schema;
     const parentConst = retrievedSchema[CONST_KEY];
     const objectDefaults = Object.keys(retrievedSchema.properties || {}).reduce(
       (acc: GenericObjectType, key: string) => {

packages/utils/test/schema/getDefaultFormStateTest.ts

@@ -1641,6 +1641,83 @@ export default function getDefaultFormStateTest(testValidator: TestValidatorType
           ).toEqual(expected);
         });
       });
+
+      describe('an nested object with if/then condition', () => {
+        const schema: RJSFSchema = {
+          type: 'object',
+          properties: {
+            wrappingObject: {
+              type: 'object',
+              properties: {
+                checkbox: {
+                  type: 'boolean',
+                },
+              },
+              if: {
+                properties: {
+                  checkbox: {
+                    const: true,
+                  },
+                },
+                required: ['checkbox'],
+              },
+              then: {
+                properties: {
+                  foo: {
+                    type: 'string',
+                    default: 'foo value',
+                  },
+                },
+                required: ['foo'],
+              },
+            },
+          },
+        };
+        const rawFormData = {
+          wrappingObject: {
+            checkbox: true,
+          },
+        };
+        const expected = {
+          wrappingObject: {
+            checkbox: true,
+            foo: 'foo value',
+          },
+        };
+        test('getDefaultFormState', () => {
+          expect(getDefaultFormState(testValidator, schema, rawFormData, schema)).toEqual(expected);
+        });
+
+        test('computeDefaults', () => {
+          expect(
+            computeDefaults(testValidator, schema, {
+              rootSchema: schema,
+              rawFormData,
+              shouldMergeDefaultsIntoFormData: true,
+            }),
+          ).toEqual(expected);
+        });
+
+        test('getDefaultBasedOnSchemaType', () => {
+          expect(
+            getDefaultBasedOnSchemaType(testValidator, schema, {
+              rootSchema: schema,
+              rawFormData,
+              shouldMergeDefaultsIntoFormData: true,
+            }),
+          ).toEqual(expected);
+        });
+
+        test('getObjectDefaults', () => {
+          expect(
+            getObjectDefaults(testValidator, schema, {
+              rootSchema: schema,
+              rawFormData,
+              shouldMergeDefaultsIntoFormData: true,
+            }),
+          ).toEqual(expected);
+        });
+      });
     });
 
     describe('array schemas', () => {