fix: oneOf anyOf default value always using first option

packages/core/src/utils.js

@@ -3,6 +3,7 @@ import * as ReactIs from "react-is";
 import mergeAllOf from "json-schema-merge-allof";
 import fill from "core-js-pure/features/array/fill";
 import union from "lodash/union";
+import isEmpty from "lodash/isEmpty";
 import jsonpointer from "jsonpointer";
 import fields from "./components/fields";
 import widgets from "./components/widgets";
@@ -220,10 +221,22 @@ function computeDefaults(
     );
   } else if ("oneOf" in schema) {
     schema =
-      schema.oneOf[getMatchingOption(undefined, schema.oneOf, rootSchema)];
+      schema.oneOf[
+        getMatchingOption(
+          isEmpty(formData) ? undefined : formData,
+          schema.oneOf,
+          rootSchema
+        )
+      ];
   } else if ("anyOf" in schema) {
     schema =
-      schema.anyOf[getMatchingOption(undefined, schema.anyOf, rootSchema)];
+      schema.anyOf[
+        getMatchingOption(
+          isEmpty(formData) ? undefined : formData,
+          schema.anyOf,
+          rootSchema
+        )
+      ];
   }
 
   // Not defaults defined for this node, fallback to generic typed ones.

packages/core/test/oneOf_test.js

@@ -541,6 +541,43 @@ describe("oneOf", () => {
     expect(node.querySelector("input#root").value).eql("");
   });
 
+  it("should use only the selected option when generating default values", () => {
+    const schema = {
+      type: "object",
+      oneOf: [
+        {
+          additionalProperties: false,
+          properties: { lorem: { type: "object" } },
+        },
+        {
+          additionalProperties: false,
+          properties: { ipsum: { type: "object" } },
+        },
+        {
+          additionalProperties: false,
+          properties: { pyot: { type: "object" } },
+        },
+      ],
+    };
+
+    const { node, onChange } = createFormComponent({
+      schema,
+      formData: { lorem: {} },
+    });
+
+    const $select = node.querySelector("select");
+
+    Simulate.change($select, {
+      target: { value: $select.options[1].value },
+    });
+
+    expect($select.value).eql("1");
+
+    sinon.assert.calledWithMatch(onChange.lastCall, {
+      formData: { lorem: undefined, ipsum: {} },
+    });
+  });
+
   describe("Arrays", () => {
     it("should correctly render mixed types for oneOf inside array items", () => {
       const schema = {

packages/core/test/utils_test.js

@@ -657,6 +657,23 @@ describe("utils", () => {
         });
       });
 
+      it("should populate defaults for oneOf second option", () => {
+        const schema = {
+          type: "object",
+          properties: {
+            test: {
+              oneOf: [
+                { properties: { a: { type: "string", default: "a" } } },
+                { properties: { b: { type: "string", default: "b" } } },
+              ],
+            },
+          },
+        };
+        expect(getDefaultFormState(schema, { test: { b: "b" } })).eql({
+          test: { b: "b" },
+        });
+      });
+
       it("should populate defaults for oneOf when 'type': 'object' is missing", () => {
         const schema = {
           type: "object",
@@ -754,6 +771,23 @@ describe("utils", () => {
         });
       });
 
+      it("should populate defaults for anyOf second option", () => {
+        const schema = {
+          type: "object",
+          properties: {
+            test: {
+              anyOf: [
+                { properties: { a: { type: "string", default: "a" } } },
+                { properties: { b: { type: "string", default: "b" } } },
+              ],
+            },
+          },
+        };
+        expect(getDefaultFormState(schema, { test: { b: "b" } })).eql({
+          test: { b: "b" },
+        });
+      });
+
       it("should populate nested default values for anyOf", () => {
         const schema = {
           type: "object",