From a2884da5f80cc865fdc5aeb298fb30fd90887f1f Mon Sep 17 00:00:00 2001
From: Zhong <cszhjh@gmail.com>
Date: Sat, 16 Aug 2025 01:18:31 +0800
Subject: [PATCH] fix(components): [splitter] collapse works with two-way size
 and min & max (#21738)

* fix(components): [splitter] collapse works with two-way size and min

* test: fix case

* chore: rerun ci
---
 .../splitter/__tests__/splitter.test.tsx      | 54 ++++++++++++++++++-
 .../components/splitter/src/split-panel.vue   |  8 +--
 2 files changed, 57 insertions(+), 5 deletions(-)

diff --git a/packages/components/splitter/__tests__/splitter.test.tsx b/packages/components/splitter/__tests__/splitter.test.tsx
index 87f24661e4..15b58d30cd 100644
--- a/packages/components/splitter/__tests__/splitter.test.tsx
+++ b/packages/components/splitter/__tests__/splitter.test.tsx
@@ -1,4 +1,4 @@
-import { nextTick } from 'vue'
+import { nextTick, ref } from 'vue'
 import { mount } from '@vue/test-utils'
 import { afterAll, beforeAll, describe, expect, it, vi } from 'vitest'
 import { ElSplitter, ElSplitterPanel } from '../index'
@@ -217,4 +217,56 @@ describe('Splitter', () => {
     await nextTick()
     expect(onCollapse).toHaveBeenCalledWith(0, 'end', [200, 200])
   })
+
+  it('should collapse normally when size is two-way bound and min & max is set', async () => {
+    const size = ref(150)
+    const wrapper = mount(() => (
+      <div style={{ width: '400px', height: '400px' }}>
+        <ElSplitter>
+          <ElSplitterPanel
+            v-model:size={size.value}
+            collapsible
+            min={50}
+            max={200}
+          >
+            Left Panel
+          </ElSplitterPanel>
+          <ElSplitterPanel collapsible>Right Panel</ElSplitterPanel>
+        </ElSplitter>
+      </div>
+    ))
+    await nextTick()
+
+    const panels = wrapper.findAll('.el-splitter-panel')
+    const startCollapseButton = wrapper.find(
+      '.el-splitter-bar__horizontal-collapse-icon-start'
+    )
+    const endCollapseButton = wrapper.find(
+      '.el-splitter-bar__horizontal-collapse-icon-end'
+    )
+
+    // default size
+    expect(panels[0].attributes('style')).toContain('flex-basis: 150px;')
+
+    // Click collapse button
+    await startCollapseButton.trigger('click')
+    await nextTick()
+
+    // Panel should be collapsed (size = 0)
+    expect(panels[0].attributes('style')).toContain('flex-basis: 0px;')
+
+    // Click collapse button to expand
+    await endCollapseButton.trigger('click')
+    await nextTick()
+
+    // Panel should be restored to original size
+    expect(panels[0].attributes('style')).toContain('flex-basis: 150px;')
+
+    // Click collapse button  to expand
+    await endCollapseButton.trigger('click')
+    await nextTick()
+
+    // Panel should be collapsed (size = 400)
+    expect(panels[0].attributes('style')).toContain('flex-basis: 400px;')
+  })
 })
diff --git a/packages/components/splitter/src/split-panel.vue b/packages/components/splitter/src/split-panel.vue
index 96a39334af..9d71c879f9 100644
--- a/packages/components/splitter/src/split-panel.vue
+++ b/packages/components/splitter/src/split-panel.vue
@@ -115,7 +115,7 @@ let isSizeUpdating = false
 watch(
   () => props.size,
   () => {
-    if (panel.value) {
+    if (!isSizeUpdating && panel.value) {
       const size = sizeToPx(props.size)
       const maxSize = sizeToPx(props.max)
       const minSize = sizeToPx(props.min)
@@ -124,12 +124,10 @@ watch(
       const finalSize = Math.min(Math.max(size, minSize || 0), maxSize || size)
 
       if (finalSize !== size) {
-        isSizeUpdating = true
         emits('update:size', finalSize)
       }
 
       panel.value.size = finalSize
-      nextTick(() => (isSizeUpdating = false))
     }
   }
 )
@@ -137,8 +135,10 @@ watch(
 watch(
   () => panel.value?.size,
   (val) => {
-    if (!isSizeUpdating && val !== props.size) {
+    if (val !== props.size) {
+      isSizeUpdating = true
       emits('update:size', val as number)
+      nextTick(() => (isSizeUpdating = false))
     }
   }
 )