From a04385cd275ff6690a82a55b7f0b4d34ba7288b9 Mon Sep 17 00:00:00 2001
From: zhiyuanzmj <260480378@qq.com>
Date: Tue, 10 Mar 2026 21:53:33 +0800
Subject: [PATCH 1/8] fix(runtime-core): prevent removing undefined event
 handlers in mergeProps

Ensure event listeners that are explicitly null or undefined are
preserved during prop merging instead of being dropped.
---
 packages/runtime-core/__tests__/vnode.spec.ts | 3 +++
 packages/runtime-core/src/vnode.ts            | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/packages/runtime-core/__tests__/vnode.spec.ts b/packages/runtime-core/__tests__/vnode.spec.ts
index aa9d4ff35db..23f30cd283f 100644
--- a/packages/runtime-core/__tests__/vnode.spec.ts
+++ b/packages/runtime-core/__tests__/vnode.spec.ts
@@ -472,6 +472,9 @@ describe('vnode', () => {
       expect(mergeProps(props1, props3)).toMatchObject({
         onClick: clickHandler1,
       })
+      expect(mergeProps({ onClick: null })).toMatchObject({
+        onClick: null,
+      })
     })
 
     test('default', () => {
diff --git a/packages/runtime-core/src/vnode.ts b/packages/runtime-core/src/vnode.ts
index cd1ef948d73..35f9925d63e 100644
--- a/packages/runtime-core/src/vnode.ts
+++ b/packages/runtime-core/src/vnode.ts
@@ -891,6 +891,8 @@ export function mergeProps(...args: (Data & VNodeProps)[]): Data {
           ret[key] = existing
             ? [].concat(existing as any, incoming as any)
             : incoming
+        } else if (!incoming && !existing) {
+          ret[key] = incoming
         }
       } else if (key !== '') {
         ret[key] = toMerge[key]

From b69cf4d6d3ff0d19a7f2e8bfeb4d9bfb33b24893 Mon Sep 17 00:00:00 2001
From: zhiyuanzmj <260480378@qq.com>
Date: Tue, 7 Apr 2026 00:10:47 +0800
Subject: [PATCH 2/8] feat(types): support object Slots type for
 defineComponent

---
 .../dts-test/defineComponent.test-d.tsx       | 71 +++++++++++++++++++
 .../runtime-core/src/apiDefineComponent.ts    | 14 ++--
 packages/runtime-core/src/component.ts        |  4 +-
 .../src/componentPublicInstance.ts            |  6 +-
 4 files changed, 83 insertions(+), 12 deletions(-)

diff --git a/packages-private/dts-test/defineComponent.test-d.tsx b/packages-private/dts-test/defineComponent.test-d.tsx
index 6188b102b31..e6f42afe64b 100644
--- a/packages-private/dts-test/defineComponent.test-d.tsx
+++ b/packages-private/dts-test/defineComponent.test-d.tsx
@@ -1175,6 +1175,77 @@ describe('componentOptions setup should be `SetupContext`', () => {
   )
 })
 
+describe('infer slots from `SetupContext`', () => {
+  // options
+  const Foo = defineComponent({
+    setup(
+      _props,
+      _ctx: SetupContext<
+        EmitsOptions,
+        {
+          default: (props: { foo: number }) => any
+        }
+      >,
+    ) {},
+    render() {
+      this.$slots.default({ foo: 1 })
+    },
+  })
+  const foo = {} as InstanceType<typeof Foo>
+  expectType<IsAny<typeof foo.$slots.default>>(false)
+  foo.$slots.default({ foo: 1 })
+
+  const Bar = defineComponent({
+    setup(
+      _props,
+      _ctx: SetupContext<
+        EmitsOptions,
+        {
+          default: (props: { foo: number }) => any
+        }
+      >,
+    ) {},
+    render() {
+      this.$slots.default({ foo: 1 })
+    },
+  })
+  const bar = {} as InstanceType<typeof Bar>
+  expectType<IsAny<typeof bar.$slots.default>>(false)
+  bar.$slots.default({ foo: 1 })
+
+  // functional
+  const Baz = defineComponent(
+    <T,>(
+      _props: { foo: T },
+      _ctx: {
+        slots: {
+          default: (props: { foo: T }) => any
+        }
+      },
+    ) =>
+      () => [],
+  )
+  const baz = new Baz({ foo: 1 })
+  expectType<IsAny<typeof baz.$slots.default>>(false)
+  baz.$slots.default?.({ foo: 1 })
+
+  const Qux = defineComponent(
+    <T,>(
+      _props: { foo: T },
+      _ctx: SetupContext<
+        EmitsOptions,
+        {
+          default: (props: { foo: T }) => any
+        }
+      >,
+    ) =>
+      () => [],
+  )
+  const qux = new Qux({ foo: 1 })
+  expectType<IsAny<typeof qux.$slots.default>>(false)
+  qux.$slots.default?.({ foo: 1 })
+})
+
 describe('extract instance type', () => {
   const Base = defineComponent({
     props: {
diff --git a/packages/runtime-core/src/apiDefineComponent.ts b/packages/runtime-core/src/apiDefineComponent.ts
index 4865c3b4ea4..e17216cef28 100644
--- a/packages/runtime-core/src/apiDefineComponent.ts
+++ b/packages/runtime-core/src/apiDefineComponent.ts
@@ -33,7 +33,7 @@ import type {
   ComponentPublicInstanceConstructor,
   CreateComponentPublicInstanceWithMixins,
 } from './componentPublicInstance'
-import type { SlotsType } from './componentSlots'
+import type { Slots, SlotsType } from './componentSlots'
 import type { Directive } from './directives'
 import type { ComponentTypeEmits } from './apiSetupHelpers'
 
@@ -150,7 +150,7 @@ export function defineComponent<
   Props extends Record<string, any>,
   E extends EmitsOptions = {},
   EE extends string = string,
-  S extends SlotsType = {},
+  S extends SlotsType | Slots = {},
 >(
   setup: (
     props: Props,
@@ -166,7 +166,7 @@ export function defineComponent<
   Props extends Record<string, any>,
   E extends EmitsOptions = {},
   EE extends string = string,
-  S extends SlotsType = {},
+  S extends SlotsType | Slots = {},
 >(
   setup: (
     props: Props,
@@ -199,7 +199,7 @@ export function defineComponent<
   Extends extends ComponentOptionsMixin = ComponentOptionsMixin,
   InjectOptions extends ComponentInjectOptions = {},
   InjectKeys extends string = string,
-  Slots extends SlotsType = {},
+  TypeSlots extends SlotsType | Slots = {},
   LocalComponents extends Record<string, Component> = {},
   Directives extends Record<string, Directive> = {},
   Exposed extends string = string,
@@ -249,7 +249,7 @@ export function defineComponent<
     {}, // Defaults
     InjectOptions,
     InjectKeys,
-    Slots,
+    TypeSlots,
     LocalComponents,
     Directives,
     Exposed,
@@ -269,7 +269,7 @@ export function defineComponent<
         {},
         false,
         InjectOptions,
-        Slots,
+        TypeSlots,
         LocalComponents,
         Directives,
         string
@@ -288,7 +288,7 @@ export function defineComponent<
   PublicProps,
   ToResolvedProps<InferredProps, ResolvedEmits>,
   ExtractDefaultPropTypes<RuntimePropsOptions>,
-  Slots,
+  TypeSlots,
   LocalComponents,
   Directives,
   Exposed,
diff --git a/packages/runtime-core/src/component.ts b/packages/runtime-core/src/component.ts
index c46741bee80..ec6e399418d 100644
--- a/packages/runtime-core/src/component.ts
+++ b/packages/runtime-core/src/component.ts
@@ -287,11 +287,11 @@ export type LifecycleHook<TFn = Function> = (TFn & SchedulerJob)[] | null
 // use `E extends any` to force evaluating type to fix #2362
 export type SetupContext<
   E = EmitsOptions,
-  S extends SlotsType = {},
+  S extends SlotsType | Slots = {},
 > = E extends any
   ? {
       attrs: Attrs
-      slots: UnwrapSlotsType<S>
+      slots: S extends SlotsType ? UnwrapSlotsType<S> : Readonly<S>
       emit: EmitFn<E>
       expose: <Exposed extends Record<string, any> = Record<string, any>>(
         exposed?: Exposed,
diff --git a/packages/runtime-core/src/componentPublicInstance.ts b/packages/runtime-core/src/componentPublicInstance.ts
index 8d3fdb056a9..3add965863f 100644
--- a/packages/runtime-core/src/componentPublicInstance.ts
+++ b/packages/runtime-core/src/componentPublicInstance.ts
@@ -50,7 +50,7 @@ import {
   shouldCacheAccess,
 } from './componentOptions'
 import type { EmitFn, EmitsOptions } from './componentEmits'
-import type { SlotsType, UnwrapSlotsType } from './componentSlots'
+import type { Slots, SlotsType, UnwrapSlotsType } from './componentSlots'
 import { markAttrsAccessed } from './componentRenderUtils'
 import { currentRenderingInstance } from './componentRenderContext'
 import { warn } from './warning'
@@ -224,7 +224,7 @@ export type CreateComponentPublicInstanceWithMixins<
   Defaults = {},
   MakeDefaultsOptional extends boolean = false,
   I extends ComponentInjectOptions = {},
-  S extends SlotsType = {},
+  S extends SlotsType | Slots = {},
   LC extends Record<string, Component> = {},
   Directives extends Record<string, Directive> = {},
   Exposed extends string = string,
@@ -272,7 +272,7 @@ export type CreateComponentPublicInstanceWithMixins<
     Provide
   >,
   I,
-  S,
+  S extends SlotsType ? S : SlotsType<S>,
   Exposed,
   TypeRefs,
   TypeEl

From 16762ce011798141637997c9e154058ff0082bf4 Mon Sep 17 00:00:00 2001
From: zhiyuanzmj <260480378@qq.com>
Date: Tue, 7 Apr 2026 00:21:13 +0800
Subject: [PATCH 3/8] chore: update

---
 .../dts-test/defineComponent.test-d.tsx       | 21 +++++++++----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/packages-private/dts-test/defineComponent.test-d.tsx b/packages-private/dts-test/defineComponent.test-d.tsx
index e6f42afe64b..5c3fe71da83 100644
--- a/packages-private/dts-test/defineComponent.test-d.tsx
+++ b/packages-private/dts-test/defineComponent.test-d.tsx
@@ -1198,12 +1198,11 @@ describe('infer slots from `SetupContext`', () => {
   const Bar = defineComponent({
     setup(
       _props,
-      _ctx: SetupContext<
-        EmitsOptions,
-        {
+      _ctx: {
+        slots: {
           default: (props: { foo: number }) => any
         }
-      >,
+      },
     ) {},
     render() {
       this.$slots.default({ foo: 1 })
@@ -1217,11 +1216,12 @@ describe('infer slots from `SetupContext`', () => {
   const Baz = defineComponent(
     <T,>(
       _props: { foo: T },
-      _ctx: {
-        slots: {
+      _ctx: SetupContext<
+        EmitsOptions,
+        {
           default: (props: { foo: T }) => any
         }
-      },
+      >,
     ) =>
       () => [],
   )
@@ -1232,12 +1232,11 @@ describe('infer slots from `SetupContext`', () => {
   const Qux = defineComponent(
     <T,>(
       _props: { foo: T },
-      _ctx: SetupContext<
-        EmitsOptions,
-        {
+      _ctx: {
+        slots: {
           default: (props: { foo: T }) => any
         }
-      >,
+      },
     ) =>
       () => [],
   )

From 6dc9ed7d6cb65b3d3a02b4484a0ec6903c1186e0 Mon Sep 17 00:00:00 2001
From: zhiyuanzmj <260480378@qq.com>
Date: Tue, 7 Apr 2026 00:24:34 +0800
Subject: [PATCH 4/8] chore: update

---
 packages-private/dts-test/defineComponent.test-d.tsx | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages-private/dts-test/defineComponent.test-d.tsx b/packages-private/dts-test/defineComponent.test-d.tsx
index 5c3fe71da83..93aea41b641 100644
--- a/packages-private/dts-test/defineComponent.test-d.tsx
+++ b/packages-private/dts-test/defineComponent.test-d.tsx
@@ -1227,7 +1227,7 @@ describe('infer slots from `SetupContext`', () => {
   )
   const baz = new Baz({ foo: 1 })
   expectType<IsAny<typeof baz.$slots.default>>(false)
-  baz.$slots.default?.({ foo: 1 })
+  baz.$slots.default({ foo: 1 })
 
   const Qux = defineComponent(
     <T,>(
@@ -1242,7 +1242,7 @@ describe('infer slots from `SetupContext`', () => {
   )
   const qux = new Qux({ foo: 1 })
   expectType<IsAny<typeof qux.$slots.default>>(false)
-  qux.$slots.default?.({ foo: 1 })
+  qux.$slots.default({ foo: 1 })
 })
 
 describe('extract instance type', () => {

From b98f262653c8cd158697c2b847fad6d4ea624e26 Mon Sep 17 00:00:00 2001
From: zhiyuanzmj <260480378@qq.com>
Date: Tue, 7 Apr 2026 00:42:40 +0800
Subject: [PATCH 5/8] chore: update

---
 packages-private/dts-test/defineComponent.test-d.tsx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages-private/dts-test/defineComponent.test-d.tsx b/packages-private/dts-test/defineComponent.test-d.tsx
index 93aea41b641..9e341a5831c 100644
--- a/packages-private/dts-test/defineComponent.test-d.tsx
+++ b/packages-private/dts-test/defineComponent.test-d.tsx
@@ -2,6 +2,7 @@ import {
   type Component,
   type ComponentOptions,
   type ComponentPublicInstance,
+  type EmitsOptions,
   type PropType,
   type SetupContext,
   type Slots,
@@ -1820,7 +1821,6 @@ import type {
   ComponentOptionsMixin,
   DefineComponent,
   Directive,
-  EmitsOptions,
   ExtractPropTypes,
   KeepAliveProps,
   TransitionProps,

From 94a719b825042445fa141539363f0ca5d4d9d147 Mon Sep 17 00:00:00 2001
From: zhiyuanzmj <260480378@qq.com>
Date: Wed, 8 Apr 2026 23:20:14 +0800
Subject: [PATCH 6/8] chore: update

---
 packages-private/dts-test/defineComponent.test-d.tsx | 8 ++++----
 packages/runtime-core/src/apiDefineComponent.ts      | 8 ++++----
 packages/runtime-core/src/component.ts               | 2 +-
 packages/runtime-core/src/componentPublicInstance.ts | 4 ++--
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/packages-private/dts-test/defineComponent.test-d.tsx b/packages-private/dts-test/defineComponent.test-d.tsx
index 9e341a5831c..b5188405b30 100644
--- a/packages-private/dts-test/defineComponent.test-d.tsx
+++ b/packages-private/dts-test/defineComponent.test-d.tsx
@@ -1184,7 +1184,7 @@ describe('infer slots from `SetupContext`', () => {
       _ctx: SetupContext<
         EmitsOptions,
         {
-          default: (props: { foo: number }) => any
+          default: (props: { foo: number }) => VNode
         }
       >,
     ) {},
@@ -1201,7 +1201,7 @@ describe('infer slots from `SetupContext`', () => {
       _props,
       _ctx: {
         slots: {
-          default: (props: { foo: number }) => any
+          default: (props: { foo: number }) => VNode
         }
       },
     ) {},
@@ -1220,7 +1220,7 @@ describe('infer slots from `SetupContext`', () => {
       _ctx: SetupContext<
         EmitsOptions,
         {
-          default: (props: { foo: T }) => any
+          default: (props: { foo: T }) => VNode
         }
       >,
     ) =>
@@ -1235,7 +1235,7 @@ describe('infer slots from `SetupContext`', () => {
       _props: { foo: T },
       _ctx: {
         slots: {
-          default: (props: { foo: T }) => any
+          default: (props: { foo: T }) => VNode
         }
       },
     ) =>
diff --git a/packages/runtime-core/src/apiDefineComponent.ts b/packages/runtime-core/src/apiDefineComponent.ts
index e17216cef28..6dd1f89214e 100644
--- a/packages/runtime-core/src/apiDefineComponent.ts
+++ b/packages/runtime-core/src/apiDefineComponent.ts
@@ -33,7 +33,7 @@ import type {
   ComponentPublicInstanceConstructor,
   CreateComponentPublicInstanceWithMixins,
 } from './componentPublicInstance'
-import type { Slots, SlotsType } from './componentSlots'
+import type { SlotsType } from './componentSlots'
 import type { Directive } from './directives'
 import type { ComponentTypeEmits } from './apiSetupHelpers'
 
@@ -150,7 +150,7 @@ export function defineComponent<
   Props extends Record<string, any>,
   E extends EmitsOptions = {},
   EE extends string = string,
-  S extends SlotsType | Slots = {},
+  S extends SlotsType | Record<string, any> = {},
 >(
   setup: (
     props: Props,
@@ -166,7 +166,7 @@ export function defineComponent<
   Props extends Record<string, any>,
   E extends EmitsOptions = {},
   EE extends string = string,
-  S extends SlotsType | Slots = {},
+  S extends SlotsType | Record<string, any> = {},
 >(
   setup: (
     props: Props,
@@ -199,7 +199,7 @@ export function defineComponent<
   Extends extends ComponentOptionsMixin = ComponentOptionsMixin,
   InjectOptions extends ComponentInjectOptions = {},
   InjectKeys extends string = string,
-  TypeSlots extends SlotsType | Slots = {},
+  TypeSlots extends SlotsType | Record<string, any> = {},
   LocalComponents extends Record<string, Component> = {},
   Directives extends Record<string, Directive> = {},
   Exposed extends string = string,
diff --git a/packages/runtime-core/src/component.ts b/packages/runtime-core/src/component.ts
index ec6e399418d..93847406d8f 100644
--- a/packages/runtime-core/src/component.ts
+++ b/packages/runtime-core/src/component.ts
@@ -287,7 +287,7 @@ export type LifecycleHook<TFn = Function> = (TFn & SchedulerJob)[] | null
 // use `E extends any` to force evaluating type to fix #2362
 export type SetupContext<
   E = EmitsOptions,
-  S extends SlotsType | Slots = {},
+  S extends SlotsType | Record<string, any> = {},
 > = E extends any
   ? {
       attrs: Attrs
diff --git a/packages/runtime-core/src/componentPublicInstance.ts b/packages/runtime-core/src/componentPublicInstance.ts
index 3add965863f..68e9fd794c4 100644
--- a/packages/runtime-core/src/componentPublicInstance.ts
+++ b/packages/runtime-core/src/componentPublicInstance.ts
@@ -50,7 +50,7 @@ import {
   shouldCacheAccess,
 } from './componentOptions'
 import type { EmitFn, EmitsOptions } from './componentEmits'
-import type { Slots, SlotsType, UnwrapSlotsType } from './componentSlots'
+import type { SlotsType, UnwrapSlotsType } from './componentSlots'
 import { markAttrsAccessed } from './componentRenderUtils'
 import { currentRenderingInstance } from './componentRenderContext'
 import { warn } from './warning'
@@ -224,7 +224,7 @@ export type CreateComponentPublicInstanceWithMixins<
   Defaults = {},
   MakeDefaultsOptional extends boolean = false,
   I extends ComponentInjectOptions = {},
-  S extends SlotsType | Slots = {},
+  S extends SlotsType | Record<string, any> = {},
   LC extends Record<string, Component> = {},
   Directives extends Record<string, Directive> = {},
   Exposed extends string = string,

From 3c921991bc24a7983078aabb1489b050002defc6 Mon Sep 17 00:00:00 2001
From: zhiyuanzmj <260480378@qq.com>
Date: Wed, 8 Apr 2026 23:23:55 +0800
Subject: [PATCH 7/8] chore: update

---
 packages/runtime-core/src/apiDefineComponent.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/runtime-core/src/apiDefineComponent.ts b/packages/runtime-core/src/apiDefineComponent.ts
index 6dd1f89214e..b18daf49dde 100644
--- a/packages/runtime-core/src/apiDefineComponent.ts
+++ b/packages/runtime-core/src/apiDefineComponent.ts
@@ -199,7 +199,7 @@ export function defineComponent<
   Extends extends ComponentOptionsMixin = ComponentOptionsMixin,
   InjectOptions extends ComponentInjectOptions = {},
   InjectKeys extends string = string,
-  TypeSlots extends SlotsType | Record<string, any> = {},
+  Slots extends SlotsType | Record<string, any> = {},
   LocalComponents extends Record<string, Component> = {},
   Directives extends Record<string, Directive> = {},
   Exposed extends string = string,
@@ -249,7 +249,7 @@ export function defineComponent<
     {}, // Defaults
     InjectOptions,
     InjectKeys,
-    TypeSlots,
+    Slots,
     LocalComponents,
     Directives,
     Exposed,
@@ -269,7 +269,7 @@ export function defineComponent<
         {},
         false,
         InjectOptions,
-        TypeSlots,
+        Slots,
         LocalComponents,
         Directives,
         string
@@ -288,7 +288,7 @@ export function defineComponent<
   PublicProps,
   ToResolvedProps<InferredProps, ResolvedEmits>,
   ExtractDefaultPropTypes<RuntimePropsOptions>,
-  TypeSlots,
+  Slots,
   LocalComponents,
   Directives,
   Exposed,

From d937991803f3b90eb49b476ff13e2d4dc72749ea Mon Sep 17 00:00:00 2001
From: zhiyuanzmj <260480378@qq.com>
Date: Thu, 9 Apr 2026 08:29:59 +0800
Subject: [PATCH 8/8] chore: update test

---
 .../dts-test/defineComponent.test-d.tsx       | 25 ++++++++-----------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/packages-private/dts-test/defineComponent.test-d.tsx b/packages-private/dts-test/defineComponent.test-d.tsx
index b5188405b30..084bd44dcba 100644
--- a/packages-private/dts-test/defineComponent.test-d.tsx
+++ b/packages-private/dts-test/defineComponent.test-d.tsx
@@ -1181,12 +1181,7 @@ describe('infer slots from `SetupContext`', () => {
   const Foo = defineComponent({
     setup(
       _props,
-      _ctx: SetupContext<
-        EmitsOptions,
-        {
-          default: (props: { foo: number }) => VNode
-        }
-      >,
+      _ctx: SetupContext<EmitsOptions, { default: { foo: number } }>,
     ) {},
     render() {
       this.$slots.default({ foo: 1 })
@@ -1216,15 +1211,16 @@ describe('infer slots from `SetupContext`', () => {
   // functional
   const Baz = defineComponent(
     <T,>(
-      _props: { foo: T },
-      _ctx: SetupContext<
+      props: { foo: T },
+      ctx: SetupContext<
         EmitsOptions,
-        {
+        SlotsType<{
           default: (props: { foo: T }) => VNode
-        }
+        }>
       >,
     ) =>
-      () => [],
+      () =>
+        ctx.slots.default(props),
   )
   const baz = new Baz({ foo: 1 })
   expectType<IsAny<typeof baz.$slots.default>>(false)
@@ -1232,14 +1228,15 @@ describe('infer slots from `SetupContext`', () => {
 
   const Qux = defineComponent(
     <T,>(
-      _props: { foo: T },
-      _ctx: {
+      props: { foo: T },
+      ctx: {
         slots: {
           default: (props: { foo: T }) => VNode
         }
       },
     ) =>
-      () => [],
+      () =>
+        ctx.slots.default(props),
   )
   const qux = new Qux({ foo: 1 })
   expectType<IsAny<typeof qux.$slots.default>>(false)