[core] Port rjsf-team/react-jsonschema-form#4889 (#253)

Author: x0k

.changeset/humble-spoons-smell.md

@@ -0,0 +1,5 @@
+---
+"@sjsf/form": patch
+---
+
+Port https://github.com/rjsf-team/react-jsonschema-form/pull/4889

packages/form/src/core/default-state.test.ts

@@ -2535,6 +2535,154 @@ describe("getDefaultFormState()", () => {
         ).toEqual(expected);
       });
     });
+
+    describe("an nested object with if/then condition", () => {
+      const schema: Schema = {
+        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",
+        },
+      };
+
+      beforeEach(() => {
+        testValidator = createValidator({
+          cases: [
+            {
+              schema: {
+                properties: { checkbox: { const: true } },
+                required: ["checkbox"],
+              },
+              value: { checkbox: true },
+              result: true,
+            },
+            {
+              schema: {
+                properties: { checkbox: { const: true } },
+                required: ["checkbox"],
+              },
+              value: {},
+              result: false
+            },
+          ],
+        });
+        defaultMerger = createMerger({
+          merges: [
+            {
+              left: {
+                type: "object",
+                properties: { checkbox: { type: "boolean" } },
+              },
+              right: {
+                properties: {
+                  foo: { type: "string", default: "foo value" },
+                },
+                required: ["foo"],
+              },
+              result: {
+                type: "object",
+                properties: {
+                  checkbox: { type: "boolean" },
+                  foo: { type: "string", default: "foo value" },
+                },
+                required: ["foo"],
+              },
+            },
+          ],
+        });
+      });
+
+      test("getDefaultFormState", () => {
+        expect(
+          getDefaultFormState(
+            testValidator,
+            defaultMerger,
+            schema,
+            rawFormData,
+            schema
+          )
+        ).toEqual(expected);
+      });
+
+      test("computeDefaults", () => {
+        expect(
+          computeDefaults(testValidator, defaultMerger, schema, {
+            ...defaults,
+            rootSchema: schema,
+            rawFormData,
+            shouldMergeDefaultsIntoFormData: true,
+          })
+        ).toEqual(expected);
+      });
+
+      test("getDefaultBasedOnSchemaType", () => {
+        expect(
+          getDefaultBasedOnSchemaType(
+            testValidator,
+            defaultMerger,
+            schema,
+            {
+              ...defaults,
+              rootSchema: schema,
+              rawFormData,
+              shouldMergeDefaultsIntoFormData: true,
+            },
+            undefined
+          )
+        ).toEqual(expected);
+      });
+
+      test("getObjectDefaults", () => {
+        expect(
+          getObjectDefaults(
+            testValidator,
+            defaultMerger,
+            schema,
+            {
+              ...defaults,
+              rootSchema: schema,
+              rawFormData,
+              shouldMergeDefaultsIntoFormData: true,
+            },
+            undefined
+          )
+        ).toEqual(expected);
+      });
+    });
   });
 
   describe("array schemas", () => {

packages/form/src/core/default-state.ts

@@ -9,6 +9,7 @@ import { resolveDependencies, retrieveSchema } from "./resolve.js";
 import {
   ALL_OF_KEY,
   DEPENDENCIES_KEY,
+  IF_KEY,
   type Schema,
   type SchemaArrayValue,
   type SchemaObjectValue,
@@ -682,13 +683,19 @@ export function getObjectDefaults(
   }: ComputeDefaultsProps<SchemaObjectValue>,
   defaults: SchemaValue | undefined
 ): SchemaObjectValue | null {
-  // 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(validator, merger, schema, rootSchema, formData)
-      : 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(validator, merger, schema, rootSchema, formData)
+    : schema;
   const retrievedSchemaRequired = new Set(retrievedSchema.required);
   const parentConstObject = isSchemaObjectValue(retrievedSchema.const)
     ? retrievedSchema.const