fix: stable route ordering for group folders with same path

Group folders like (user) and (user-home) both resolve to an empty path
segment, making TreeNode.compare return 0 and fall back to non-deterministic
insertion order. Use rawSegment as tiebreaker for stable sorting.

Author: posva

packages/router/src/unplugin/codegen/generateRouteFileInfoMap.spec.ts

@@ -226,6 +226,30 @@ describe('generateRouteFileInfoMap', () => {
     `)
   })
 
+  it('produces stable output for sibling group folders with same path', () => {
+    const createTree = (insertionOrder: string[]) => {
+      const tree = new PrefixTree(DEFAULT_OPTIONS)
+      insertionOrder.forEach(route => {
+        tree.insert(route, `${route}.vue`)
+      })
+      return formatExports(generateRouteFileInfoMap(tree, { root: '' }))
+    }
+
+    const order1 = [
+      '[username]/(user)/profile',
+      '[username]/(user-home)/(user-home)',
+    ]
+    const order2 = [
+      '[username]/(user-home)/(user-home)',
+      '[username]/(user)/profile',
+    ]
+
+    const result1 = createTree(order1)
+    const result2 = createTree(order2)
+
+    expect(result1).toBe(result2)
+  })
+
   it('works with children', () => {
     const tree = new PrefixTree(DEFAULT_OPTIONS)
     tree.insert('parent', 'src/pages/parent.vue')

packages/router/src/unplugin/codegen/generateRouteMap.spec.ts

@@ -684,6 +684,34 @@ describe('generateRouteNamedMap', () => {
     `)
   })
 
+  it('produces stable output for sibling group folders with same path', () => {
+    const createTree = (insertionOrder: string[]) => {
+      const tree = new PrefixTree(DEFAULT_OPTIONS)
+      insertionOrder.forEach(route => {
+        tree.insert(route, `${route}.vue`)
+      })
+      return formatExports(
+        generateRouteNamedMap(tree, DEFAULT_OPTIONS, new Map())
+      )
+    }
+
+    // Group folders (user) and (user-home) both resolve to empty path segments
+    // but should produce stable output regardless of insertion order
+    const order1 = [
+      '[username]/(user)/profile',
+      '[username]/(user-home)/(user-home)',
+    ]
+    const order2 = [
+      '[username]/(user-home)/(user-home)',
+      '[username]/(user)/profile',
+    ]
+
+    const result1 = createTree(order1)
+    const result2 = createTree(order2)
+
+    expect(result1).toBe(result2)
+  })
+
   it('treats files named with parentheses as index inside static folder', () => {
     const tree = new PrefixTree(DEFAULT_OPTIONS)
 

packages/router/src/unplugin/core/tree.ts

@@ -182,7 +182,10 @@ export class TreeNode {
   static compare(a: TreeNode, b: TreeNode): number {
     // for this case, ASCII, short list, it's better than Internation Collator
     // https://stackoverflow.com/questions/77246375/why-localecompare-can-be-faster-than-collator-compare
-    return a.path.localeCompare(b.path, 'en')
+    return (
+      a.path.localeCompare(b.path, 'en') ||
+      a.value.rawSegment.localeCompare(b.value.rawSegment, 'en')
+    )
   }
 
   /**