Nested data traversal for correcting invalid types didn't stop at a valid value, replacing paths with default data further down the tree.

Author: ciscoheat

CHANGELOG.md

@@ -5,6 +5,12 @@ Headlines: Added, Changed, Deprecated, Removed, Fixed, Security
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Fixed
+
+- Nested data traversal for correcting invalid types didn't stop at a valid value, replacing paths with default data further down the tree.
+
 ## [2.27.1] - 2025-06-27
 
 ### Fixed

src/lib/errors.ts

@@ -249,10 +249,7 @@ export function replaceInvalidDefaults<T extends Record<string, unknown>>(
 
 	//#region Defaults
 
-	function Defaults_traverseAndReplace(
-		defaultPath: Partial<PathData>,
-		traversingErrors = false
-	): void {
+	function Defaults_traverseAndReplace(defaultPath: Partial<PathData>, traversingErrors = false) {
 		const currentPath = defaultPath.path;
 		if (!currentPath || !currentPath[0]) return;
 		if (typeof currentPath[0] === 'string' && preprocessed?.includes(currentPath[0])) return;
@@ -292,7 +289,11 @@ export function replaceInvalidDefaults<T extends Record<string, unknown>>(
 
 			const fieldType = pathTypes.value ?? defaultType;
 			if (fieldType) {
-				Data_setValue(currentPath, Types_correctValue(dataValue, defValue, fieldType));
+				const corrected = Types_correctValue(dataValue, defValue, fieldType);
+				// If same value, skip the potential nested path as it's already correct.
+				if (corrected === dataValue) return 'skip';
+
+				Data_setValue(currentPath, corrected);
 			}
 		}
 	}

src/tests/zod4Union.test.ts

@@ -259,3 +259,88 @@ test('Default value with *matching* type in nested discriminated union with supe
 	} satisfies FormSchema;
 	await validate(data, FormSchema);
 });
+
+test('Default value with *matching* type in nested discriminated union with superRefine', async () => {
+	const ZodSchema2 = z
+		.object({
+			type: z.literal('additional'),
+			additional: z
+				.discriminatedUnion('type', [
+					z.object({
+						type: z.literal('same'),
+						address: z.string().nullable()
+					}),
+					z.object({
+						type: z.literal('different'),
+						address: z.string()
+					})
+				])
+				.default({
+					type: 'same',
+					address: null
+				})
+		})
+		.superRefine((_data, ctx) => {
+			ctx.addIssue({
+				code: z.ZodIssueCode.custom,
+				path: ['addresses', 'additional', 'name'],
+				message: 'error'
+			});
+		});
+
+	const FormSchema = zod(ZodSchema2);
+	type FormSchema = (typeof FormSchema)['defaults'];
+	const data = {
+		type: 'additional',
+		additional: {
+			type: 'different',
+			address: '123 Main St'
+		}
+	} satisfies FormSchema;
+	await validate(data, FormSchema);
+});
+
+test('Keep valid value in nested discriminated union', async () => {
+	const ZodSchema2 = z.object({
+		type: z.literal('additional'),
+		value: z.string(),
+		extra: z.discriminatedUnion('type', [
+			z.object({
+				type: z.literal('num'),
+				value: z.number().default(0)
+			}),
+			z.object({
+				type: z.literal('complex'),
+				value: z
+					.discriminatedUnion('type', [
+						z.object({
+							type: z.literal('string'),
+							value: z.string()
+						}),
+						z.object({
+							type: z.literal('number'),
+							value: z.number()
+						})
+					])
+					.default({
+						type: 'string',
+						value: ''
+					})
+			})
+		])
+	});
+
+	const FormSchema = zod(ZodSchema2);
+	type FormSchema = (typeof FormSchema)['defaults'];
+	const data = {
+		type: 'additional',
+		value: 'test',
+		extra: {
+			type: 'num',
+			value: 42
+		}
+	} satisfies FormSchema;
+	const result = await validate(data, FormSchema);
+
+	expect(result.data.extra.value).toBe(42);
+});

src/tests/zodUnion.test.ts

@@ -160,3 +160,56 @@ test('Default value with *matching* type in nested discriminated union with supe
 	} satisfies FormSchema;
 	await validate(data, FormSchema);
 });
+
+test('Keep valid value in nested discriminated union with superRefine', async () => {
+	const ZodSchema2 = z
+		.object({
+			type: z.literal('additional'),
+			value: z.string(),
+			extra: z.discriminatedUnion('type', [
+				z.object({
+					type: z.literal('num'),
+					value: z.number().default(0)
+				}),
+				z.object({
+					type: z.literal('complex'),
+					value: z
+						.discriminatedUnion('type', [
+							z.object({
+								type: z.literal('string'),
+								value: z.string()
+							}),
+							z.object({
+								type: z.literal('number'),
+								value: z.number()
+							})
+						])
+						.default({
+							type: 'string',
+							value: ''
+						})
+				})
+			])
+		})
+		.superRefine((_data, ctx) => {
+			ctx.addIssue({
+				code: z.ZodIssueCode.custom,
+				path: ['value'],
+				message: 'error'
+			});
+		});
+
+	const FormSchema = zod(ZodSchema2);
+	type FormSchema = (typeof FormSchema)['defaults'];
+	const data = {
+		type: 'additional',
+		value: 'test',
+		extra: {
+			type: 'num',
+			value: 42
+		}
+	} satisfies FormSchema;
+	const result = await validate(data, FormSchema);
+
+	expect(result.data.extra.value).toBe(42);
+});