fix: fullpath handling

e2e/react-router/basic-file-based/src/routes/__root.tsx

@@ -164,6 +164,15 @@ function RootComponent() {
           }}
         >
           Pathless Layout
+        </Link>{' '}
+        <Link
+          to="/fullpath-test"
+          data-testid="link-to-fullpath-test"
+          activeProps={{
+            className: 'font-bold',
+          }}
+        >
+          FullPath Test
         </Link>
       </div>
       <hr />

e2e/react-router/basic-file-based/src/routes/fullpath-test/_layout/$id.tsx

@@ -0,0 +1,23 @@
+import { createFileRoute, useMatches } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/fullpath-test/_layout/$id')({
+  component: IdComponent,
+})
+
+function IdComponent() {
+  const matches = useMatches()
+  const { id } = Route.useParams()
+  // Find this route's match by routeId
+  const idMatch = matches.find(
+    (m) => m.routeId === '/fullpath-test/_layout/$id',
+  )
+
+  return (
+    <div>
+      <div data-testid="param-route-fullpath">
+        {idMatch?.fullPath ?? 'undefined'}
+      </div>
+      <div data-testid="fullpath-test-param">Param: {id}</div>
+    </div>
+  )
+}

e2e/react-router/basic-file-based/src/routes/fullpath-test/_layout/index.tsx

@@ -0,0 +1,23 @@
+import { createFileRoute, useMatches } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/fullpath-test/_layout/')({
+  component: IndexComponent,
+})
+
+function IndexComponent() {
+  const matches = useMatches()
+  // Find this index route's match by routeId
+  const indexMatch = matches.find(
+    (m) => m.routeId === '/fullpath-test/_layout/',
+  )
+
+  return (
+    <div>
+      <div data-testid="index-route-fullpath">
+        {indexMatch?.fullPath ?? 'undefined'}
+      </div>
+      <div data-testid="index-route-to">{Route.to}</div>
+      <div data-testid="fullpath-test-index">FullPath Test Index</div>
+    </div>
+  )
+}

e2e/react-router/basic-file-based/src/routes/fullpath-test/_layout/route.tsx

@@ -0,0 +1,22 @@
+import { Outlet, createFileRoute, useMatches } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/fullpath-test/_layout')({
+  component: LayoutComponent,
+})
+
+function LayoutComponent() {
+  const matches = useMatches()
+  // Find this layout's match by routeId
+  const layoutMatch = matches.find(
+    (m) => m.routeId === '/fullpath-test/_layout',
+  )
+
+  return (
+    <div>
+      <div data-testid="pathless-layout-fullpath">
+        {layoutMatch?.fullPath ?? 'undefined'}
+      </div>
+      <Outlet />
+    </div>
+  )
+}

e2e/react-router/basic-file-based/src/routes/fullpath-test/route.tsx

@@ -0,0 +1,10 @@
+import { Outlet, createFileRoute } from '@tanstack/react-router'
+
+export const Route = createFileRoute('/fullpath-test')({
+  component: () => (
+    <div>
+      <h2 data-testid="fullpath-test-header">FullPath Test Section</h2>
+      <Outlet />
+    </div>
+  ),
+})

e2e/react-router/basic-file-based/src/routes/relative/link/path/$path/index.tsx

@@ -17,7 +17,7 @@ function RouteComponent() {
       </div>
       <div>
         <Link
-          from="/relative/link/path"
+          from="/relative/link/path/"
           to="./$path"
           params={{ path: path === 'a' ? 'b' : 'a' }}
           className="mr-2"

e2e/react-router/basic-file-based/src/routes/relative/useNavigate/path/$path/index.tsx

@@ -24,7 +24,7 @@ function RouteComponent() {
         <button
           onClick={() =>
             navigate({
-              from: '/relative/useNavigate/path',
+              from: '/relative/useNavigate/path/',
               to: './$path',
               params: { path: path === 'a' ? 'b' : 'a' },
             })

e2e/react-router/basic-file-based/tests/fullpath-types.spec.ts

@@ -0,0 +1,81 @@
+import { expect, test } from '@playwright/test'
+
+test.describe('FullPath type/runtime match (Issues #4892, #2675, #6403)', () => {
+  test.describe('Pathless layout routes should have parent fullPath, not empty string', () => {
+    test('direct navigation to pathless layout shows correct fullPath', async ({
+      page,
+    }) => {
+      await page.goto('/fullpath-test')
+      // The pathless layout's fullPath should be '/fullpath-test' (same as parent), not ''
+      await expect(page.getByTestId('pathless-layout-fullpath')).toHaveText(
+        '/fullpath-test',
+      )
+    })
+
+    test('client-side navigation to pathless layout shows correct fullPath', async ({
+      page,
+    }) => {
+      await page.goto('/')
+      await page.getByTestId('link-to-fullpath-test').click()
+      await expect(page.getByTestId('pathless-layout-fullpath')).toHaveText(
+        '/fullpath-test',
+      )
+    })
+  })
+
+  test.describe('Index routes should have trailing slash in fullPath', () => {
+    test('direct navigation to index route shows fullPath with trailing slash', async ({
+      page,
+    }) => {
+      await page.goto('/fullpath-test')
+      // The index route's fullPath should be '/fullpath-test/' (with trailing slash)
+      await expect(page.getByTestId('index-route-fullpath')).toHaveText(
+        '/fullpath-test/',
+      )
+    })
+
+    test('param route under pathless layout shows correct fullPath', async ({
+      page,
+    }) => {
+      await page.goto('/fullpath-test/123')
+      // The param route's fullPath should be '/fullpath-test/$id'
+      await expect(page.getByTestId('param-route-fullpath')).toHaveText(
+        '/fullpath-test/$id',
+      )
+      await expect(page.getByTestId('fullpath-test-param')).toHaveText(
+        'Param: 123',
+      )
+    })
+  })
+
+  test.describe('Route.to should NOT have trailing slash (Issue #3005)', () => {
+    test('index route Route.to should not have trailing slash', async ({
+      page,
+    }) => {
+      await page.goto('/fullpath-test')
+      // Route.to should be '/fullpath-test' (without trailing slash)
+      // while Route.fullPath is '/fullpath-test/' (with trailing slash)
+      await expect(page.getByTestId('index-route-to')).toHaveText(
+        '/fullpath-test',
+      )
+    })
+  })
+
+  test.describe('Existing pathless layout routes', () => {
+    test('existing pathless layout index shows correct fullPath at runtime', async ({
+      page,
+    }) => {
+      // This tests the existing /pathless-layout route which has a pathless _layout
+      await page.goto('/pathless-layout')
+      await expect(page.getByTestId('pathless-layout-header')).toContainText(
+        'Pathless Layout Section',
+      )
+      await expect(page.getByTestId('pathless-layout-wrapper')).toContainText(
+        'Pathless Layout Wrapper',
+      )
+      await expect(page.getByTestId('pathless-layout-index')).toContainText(
+        'Pathless Layout Index',
+      )
+    })
+  })
+})

e2e/react-router/basic-virtual-file-based/src/routeTree.gen.ts

@@ -178,7 +178,7 @@ declare module '@tanstack/react-router' {
     '/_first': {
       id: '/_first'
       path: ''
-      fullPath: ''
+      fullPath: '/'
       preLoaderRoute: typeof layoutFirstLayoutRouteImport
       parentRoute: typeof rootRouteImport
     }
@@ -199,7 +199,7 @@ declare module '@tanstack/react-router' {
     '/_first/_second': {
       id: '/_first/_second'
       path: ''
-      fullPath: ''
+      fullPath: '/'
       preLoaderRoute: typeof layoutSecondLayoutRouteImport
       parentRoute: typeof layoutFirstLayoutRoute
     }

e2e/react-start/basic/src/routeTree.gen.ts

@@ -354,11 +354,11 @@ export interface FileRoutesByFullPath {
   '/search-params/default': typeof SearchParamsDefaultRoute
   '/search-params/loader-throws-redirect': typeof SearchParamsLoaderThrowsRedirectRoute
   '/users/$userId': typeof UsersUserIdRoute
-  '/multi-cookie-redirect': typeof MultiCookieRedirectIndexRoute
+  '/multi-cookie-redirect/': typeof MultiCookieRedirectIndexRoute
   '/not-found/': typeof NotFoundIndexRoute
   '/posts/': typeof PostsIndexRoute
   '/raw-stream/': typeof RawStreamIndexRoute
-  '/redirect': typeof RedirectIndexRoute
+  '/redirect/': typeof RedirectIndexRoute
   '/search-params/': typeof SearchParamsIndexRoute
   '/users/': typeof UsersIndexRoute
   '/layout-a': typeof LayoutLayout2LayoutARoute
@@ -372,7 +372,7 @@ export interface FileRoutesByFullPath {
   '/redirect/$target/serverFn/via-beforeLoad': typeof RedirectTargetServerFnViaBeforeLoadRoute
   '/redirect/$target/serverFn/via-loader': typeof RedirectTargetServerFnViaLoaderRoute
   '/redirect/$target/serverFn/via-useServerFn': typeof RedirectTargetServerFnViaUseServerFnRoute
-  '/redirect/$target/serverFn': typeof RedirectTargetServerFnIndexRoute
+  '/redirect/$target/serverFn/': typeof RedirectTargetServerFnIndexRoute
   '/foo/$bar/$qux/': typeof FooBarQuxHereIndexRoute
 }
 export interface FileRoutesByTo {
@@ -505,11 +505,11 @@ export interface FileRouteTypes {
     | '/search-params/default'
     | '/search-params/loader-throws-redirect'
     | '/users/$userId'
-    | '/multi-cookie-redirect'
+    | '/multi-cookie-redirect/'
     | '/not-found/'
     | '/posts/'
     | '/raw-stream/'
-    | '/redirect'
+    | '/redirect/'
     | '/search-params/'
     | '/users/'
     | '/layout-a'
@@ -523,7 +523,7 @@ export interface FileRouteTypes {
     | '/redirect/$target/serverFn/via-beforeLoad'
     | '/redirect/$target/serverFn/via-loader'
     | '/redirect/$target/serverFn/via-useServerFn'
-    | '/redirect/$target/serverFn'
+    | '/redirect/$target/serverFn/'
     | '/foo/$bar/$qux/'
   fileRoutesByTo: FileRoutesByTo
   to:
@@ -731,7 +731,7 @@ declare module '@tanstack/react-router' {
     '/_layout': {
       id: '/_layout'
       path: ''
-      fullPath: ''
+      fullPath: '/'
       preLoaderRoute: typeof LayoutRouteImport
       parentRoute: typeof rootRouteImport
     }
@@ -773,7 +773,7 @@ declare module '@tanstack/react-router' {
     '/redirect/': {
       id: '/redirect/'
       path: '/redirect'
-      fullPath: '/redirect'
+      fullPath: '/redirect/'
       preLoaderRoute: typeof RedirectIndexRouteImport
       parentRoute: typeof rootRouteImport
     }
@@ -801,7 +801,7 @@ declare module '@tanstack/react-router' {
     '/multi-cookie-redirect/': {
       id: '/multi-cookie-redirect/'
       path: '/multi-cookie-redirect'
-      fullPath: '/multi-cookie-redirect'
+      fullPath: '/multi-cookie-redirect/'
       preLoaderRoute: typeof MultiCookieRedirectIndexRouteImport
       parentRoute: typeof rootRouteImport
     }
@@ -913,7 +913,7 @@ declare module '@tanstack/react-router' {
     '/_layout/_layout-2': {
       id: '/_layout/_layout-2'
       path: ''
-      fullPath: ''
+      fullPath: '/'
       preLoaderRoute: typeof LayoutLayout2RouteImport
       parentRoute: typeof LayoutRoute
     }
@@ -969,7 +969,7 @@ declare module '@tanstack/react-router' {
     '/redirect/$target/serverFn/': {
       id: '/redirect/$target/serverFn/'
       path: '/serverFn'
-      fullPath: '/redirect/$target/serverFn'
+      fullPath: '/redirect/$target/serverFn/'
       preLoaderRoute: typeof RedirectTargetServerFnIndexRouteImport
       parentRoute: typeof RedirectTargetRoute
     }