From d09f791e47bb6cfabf5235b87199b14e5ed74b40 Mon Sep 17 00:00:00 2001
From: daiwei <daiwei521@126.com>
Date: Fri, 4 Oct 2024 20:24:57 +0800
Subject: [PATCH 1/2] fix(types): retain union type narrowing in
 PropsWithDefaults with defaults applied

---
 .../dts-test/setupHelpers.test-d.ts           | 10 ++++++
 packages/runtime-core/src/apiSetupHelpers.ts  | 32 ++++++++++---------
 2 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/packages-private/dts-test/setupHelpers.test-d.ts b/packages-private/dts-test/setupHelpers.test-d.ts
index 4074176ff98..aeab4f9b997 100644
--- a/packages-private/dts-test/setupHelpers.test-d.ts
+++ b/packages-private/dts-test/setupHelpers.test-d.ts
@@ -58,6 +58,9 @@ describe('defineProps w/ type declaration + withDefaults', <T extends
       bool?: boolean
       boolAndUndefined: boolean | undefined
       foo?: T
+      u:
+        | { type: 'button'; buttonType?: 'submit' }
+        | { type: 'link'; href: string }
     }>(),
     {
       number: 123,
@@ -88,6 +91,13 @@ describe('defineProps w/ type declaration + withDefaults', <T extends
 
   expectType<boolean>(res.bool)
   expectType<boolean>(res.boolAndUndefined)
+
+  if (res.u.type === 'button') {
+    expectType<'submit' | undefined>(res.u.buttonType)
+  }
+  if (res.u.type === 'link') {
+    expectType<string>(res.u.href)
+  }
 })
 
 describe('defineProps w/ union type declaration + withDefaults', () => {
diff --git a/packages/runtime-core/src/apiSetupHelpers.ts b/packages/runtime-core/src/apiSetupHelpers.ts
index 33817818a93..54712c6807a 100644
--- a/packages/runtime-core/src/apiSetupHelpers.ts
+++ b/packages/runtime-core/src/apiSetupHelpers.ts
@@ -331,21 +331,23 @@ type PropsWithDefaults<
   T,
   Defaults extends InferDefaults<T>,
   BKeys extends keyof T,
-> = Readonly<MappedOmit<T, keyof Defaults>> & {
-  readonly [K in keyof Defaults as K extends keyof T
-    ? K
-    : never]-?: K extends keyof T
-    ? Defaults[K] extends undefined
-      ? IfAny<Defaults[K], NotUndefined<T[K]>, T[K]>
-      : NotUndefined<T[K]>
-    : never
-} & {
-  readonly [K in BKeys]-?: K extends keyof Defaults
-    ? Defaults[K] extends undefined
-      ? boolean | undefined
-      : boolean
-    : boolean
-}
+> = T extends unknown
+  ? Readonly<MappedOmit<T, keyof Defaults>> & {
+      readonly [K in keyof Defaults as K extends keyof T
+        ? K
+        : never]-?: K extends keyof T
+        ? Defaults[K] extends undefined
+          ? IfAny<Defaults[K], NotUndefined<T[K]>, T[K]>
+          : NotUndefined<T[K]>
+        : never
+    } & {
+      readonly [K in BKeys]-?: K extends keyof Defaults
+        ? Defaults[K] extends undefined
+          ? boolean | undefined
+          : boolean
+        : boolean
+    }
+  : never
 
 /**
  * Vue `<script setup>` compiler macro for providing props default values when

From e88722ac0612dd1fe1461a61038b2f2d81d0a25b Mon Sep 17 00:00:00 2001
From: daiwei <daiwei521@126.com>
Date: Fri, 4 Oct 2024 22:33:51 +0800
Subject: [PATCH 2/2] test: update test case

---
 .../dts-test/setupHelpers.test-d.ts           | 27 ++++++++++++-------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/packages-private/dts-test/setupHelpers.test-d.ts b/packages-private/dts-test/setupHelpers.test-d.ts
index aeab4f9b997..7b5d6f147f0 100644
--- a/packages-private/dts-test/setupHelpers.test-d.ts
+++ b/packages-private/dts-test/setupHelpers.test-d.ts
@@ -58,9 +58,6 @@ describe('defineProps w/ type declaration + withDefaults', <T extends
       bool?: boolean
       boolAndUndefined: boolean | undefined
       foo?: T
-      u:
-        | { type: 'button'; buttonType?: 'submit' }
-        | { type: 'link'; href: string }
     }>(),
     {
       number: 123,
@@ -91,13 +88,6 @@ describe('defineProps w/ type declaration + withDefaults', <T extends
 
   expectType<boolean>(res.bool)
   expectType<boolean>(res.boolAndUndefined)
-
-  if (res.u.type === 'button') {
-    expectType<'submit' | undefined>(res.u.buttonType)
-  }
-  if (res.u.type === 'link') {
-    expectType<string>(res.u.href)
-  }
 })
 
 describe('defineProps w/ union type declaration + withDefaults', () => {
@@ -250,6 +240,23 @@ describe('withDefaults w/ defineProp type is different from the defaults type',
   res1.value
 })
 
+describe('withDefaults w/ defineProp discriminate union type', () => {
+  const props = withDefaults(
+    defineProps<
+      { type: 'button'; buttonType?: 'submit' } | { type: 'link'; href: string }
+    >(),
+    {
+      type: 'button',
+    },
+  )
+  if (props.type === 'button') {
+    expectType<'submit' | undefined>(props.buttonType)
+  }
+  if (props.type === 'link') {
+    expectType<string>(props.href)
+  }
+})
+
 describe('defineProps w/ runtime declaration', () => {
   // runtime declaration
   const props = defineProps({