fix(router-core): review follow-ups for Link stack

.changeset/quiet-zeros-stay.md

@@ -0,0 +1,5 @@
+---
+'@tanstack/router-core': patch
+---
+
+Treat `0` and `false` as provided `_splat` values when interpolating paths. Only `undefined`, `null`, and `''` now omit a splat segment, matching how other path params are stringified.

benchmarks/client-nav/README.md

@@ -123,7 +123,7 @@ construction. `scenarios/mount` includes construction but also rendering and
 loading. To isolate initialization, use the core construction benchmark:
 
 ```bash
-TSR_LINK_PERF=1 CI=1 NX_DAEMON=false pnpm nx run @tanstack/router-core:test:unit --outputStyle=stream --skipRemoteCache -- bench tests/route-tree-construction.bench.ts --run --testNamePattern=1000.routes --outputJson /tmp/route-tree-construction.json
+CI=1 NX_DAEMON=false pnpm nx run @tanstack/router-core:test:unit --outputStyle=stream --skipRemoteCache -- bench tests/route-tree-construction.bench.ts --run --testNamePattern=1000.routes --outputJson /tmp/route-tree-construction.json
 ```
 
 It covers 100, 1,000, and 10,000 static, dynamic, nested, or mixed routes.
@@ -138,16 +138,16 @@ router or repeatedly initialized tree is not a construction baseline.
 
 `link-performance/` contains additional client-navigation and SSR workloads for
 focused Link work. They are **not included** in the regular client-nav/SSR
-aggregate projects or their CodSpeed build dependencies. Benchmark discovery
-also requires `TSR_LINK_PERF=1`; without it, no extended benchmark files or app
-bundles are imported.
+aggregate projects or their CodSpeed build dependencies; they only run through
+the dedicated `@benchmarks/react-link-performance` targets below. Use `-t` to
+narrow a run to specific cases.
 
 ```bash
-TSR_LINK_PERF=1 CI=1 NX_DAEMON=false pnpm nx run @benchmarks/react-link-performance:test:perf:client --outputStyle=stream --skipRemoteCache -- --run
-TSR_LINK_PERF=1 CI=1 NX_DAEMON=false pnpm nx run @benchmarks/react-link-performance:test:perf:ssr --outputStyle=stream --skipRemoteCache -- --run
+CI=1 NX_DAEMON=false pnpm nx run @benchmarks/react-link-performance:test:perf:client --outputStyle=stream --skipRemoteCache -- --run
+CI=1 NX_DAEMON=false pnpm nx run @benchmarks/react-link-performance:test:perf:ssr --outputStyle=stream --skipRemoteCache -- --run
 
 # Select a feature and save the normal Vitest JSON report.
-TSR_LINK_PERF=1 CI=1 NX_DAEMON=false pnpm nx run @benchmarks/react-link-performance:test:perf:client --outputStyle=stream --skipRemoteCache -- --run -t "updater|optional|splat" --outputJson /tmp/link-perf.json
+CI=1 NX_DAEMON=false pnpm nx run @benchmarks/react-link-performance:test:perf:client --outputStyle=stream --skipRemoteCache -- --run -t "updater|optional|splat" --outputJson /tmp/link-perf.json
 ```
 
 The cases cover repeated versus unique destination params, updater functions,
@@ -203,12 +203,12 @@ harness loader does not transpile their emitted JavaScript a second time.
 ```bash
 # Build the baseline using these same benchmark sources in its own checkout.
 # --baseline points to that checkout's link-performance/dist directory.
-TSR_LINK_PERF=1 pnpm nx run @benchmarks/react-link-performance:test:perf:stable -- \
+pnpm nx run @benchmarks/react-link-performance:test:perf:stable -- \
   --baseline /path/to/baseline/benchmarks/client-nav/link-performance/dist \
   --outputJson /tmp/paired-links.json
 
 # Narrow a comparison, or increase independent process repetitions.
-TSR_LINK_PERF=1 pnpm nx run @benchmarks/react-link-performance:test:perf:stable -- \
+pnpm nx run @benchmarks/react-link-performance:test:perf:stable -- \
   --baseline /path/to/baseline/benchmarks/client-nav/link-performance/dist \
   --mode ssr -t "middleware|unique-params" --repeats 6 \
   --outputJson /tmp/paired-links-ssr.json

benchmarks/client-nav/link-performance/config.test.ts

@@ -3,55 +3,40 @@ import { createLinkPerformanceConfig } from './config'
 
 afterEach(() => vi.unstubAllEnvs())
 
-describe.each(['client', 'ssr'] as const)(
-  '%s opt-in configuration',
-  (target) => {
-    test.each([undefined, '', '0', 'false'])(
-      'does not discover benchmarks with TSR_LINK_PERF=%s',
-      (value) => {
-        vi.stubEnv('TSR_LINK_PERF', value)
-        const config = createLinkPerformanceConfig(target)
-        expect(config.test?.benchmark?.include).toEqual([])
-        expect(config.test?.passWithNoTests).toBe(true)
-      },
-    )
-
-    test('discovers only the requested suite when explicitly enabled', () => {
-      vi.stubEnv('TSR_LINK_PERF', '1')
-      const config = createLinkPerformanceConfig(target)
-      expect(config.test?.benchmark?.include).toEqual([`${target}.bench.ts`])
-      expect(config.test?.passWithNoTests).toBe(false)
-    })
+describe.each(['client', 'ssr'] as const)('%s configuration', (target) => {
+  test('discovers only the requested suite', () => {
+    const config = createLinkPerformanceConfig(target)
+    expect(config.test?.benchmark?.include).toEqual([`${target}.bench.ts`])
+  })
 
-    test('builds production code for the correct environment', () => {
-      const config = createLinkPerformanceConfig(target)
-      expect(config.define?.['process.env.NODE_ENV']).toBe('"production"')
-      expect(config.resolve?.conditions).toContain(
-        target === 'ssr' ? 'node' : 'browser',
-      )
-      expect(config.build?.ssr).toBe(target === 'ssr')
-      expect(config.build?.outDir).toBe(`./dist/${target}`)
-      expect(config.build?.rolldownOptions?.platform).toBe('node')
-      expect(config.build?.rolldownOptions?.external).toEqual([
-        'node:module',
-        'module',
-        /^react(?:\/|$)/,
-        /^react-dom(?:\/|$)/,
-      ])
-    })
+  test('builds production code for the correct environment', () => {
+    const config = createLinkPerformanceConfig(target)
+    expect(config.define?.['process.env.NODE_ENV']).toBe('"production"')
+    expect(config.resolve?.conditions).toContain(
+      target === 'ssr' ? 'node' : 'browser',
+    )
+    expect(config.build?.ssr).toBe(target === 'ssr')
+    expect(config.build?.outDir).toBe(`./dist/${target}`)
+    expect(config.build?.rolldownOptions?.platform).toBe('node')
+    expect(config.build?.rolldownOptions?.external).toEqual([
+      'node:module',
+      'module',
+      /^react(?:\/|$)/,
+      /^react-dom(?:\/|$)/,
+    ])
+  })
 
-    test('does not retransform built bundles in the test environment', () => {
-      vi.stubEnv('VITEST', 'true')
-      const config = createLinkPerformanceConfig(target)
-      expect(config.ssr?.noExternal).toBeUndefined()
-      expect(config.test?.server?.deps?.external).toEqual([
-        /\/link-performance\/dist\//,
-      ])
-    })
+  test('does not retransform built bundles in the test environment', () => {
+    vi.stubEnv('VITEST', 'true')
+    const config = createLinkPerformanceConfig(target)
+    expect(config.ssr?.noExternal).toBeUndefined()
+    expect(config.test?.server?.deps?.external).toEqual([
+      /\/link-performance\/dist\//,
+    ])
+  })
 
-    test('bundles router dependencies when building app snapshots', () => {
-      vi.stubEnv('VITEST', undefined)
-      expect(createLinkPerformanceConfig(target).ssr?.noExternal).toBe(true)
-    })
-  },
-)
+  test('bundles router dependencies when building app snapshots', () => {
+    vi.stubEnv('VITEST', undefined)
+    expect(createLinkPerformanceConfig(target).ssr?.noExternal).toBe(true)
+  })
+})

benchmarks/client-nav/link-performance/config.ts

@@ -9,7 +9,6 @@ export function createLinkPerformanceConfig(
   target: 'client' | 'ssr',
 ): UserConfig {
   const server = target === 'ssr'
-  const enabled = process.env.TSR_LINK_PERF === '1'
 
   return {
     root,
@@ -62,9 +61,8 @@ export function createLinkPerformanceConfig(
         },
       },
       include: [],
-      passWithNoTests: !enabled,
       benchmark: {
-        include: enabled ? [`${target}.bench.ts`] : [],
+        include: [`${target}.bench.ts`],
       },
     },
   }

benchmarks/client-nav/link-performance/stable-runner.ts

@@ -159,10 +159,6 @@ async function sampleReplica(
 }
 
 async function main() {
-  if (process.env.TSR_LINK_PERF !== '1') {
-    console.log('Link performance sampling is disabled; set TSR_LINK_PERF=1.')
-    return
-  }
   const { values } = parseArgs({
     options: {
       baseline: { type: 'string' },

benchmarks/ssr/README.md

@@ -108,9 +108,8 @@ rewrites, and active props. Each timed batch creates four fresh routers and
 renders their Links to HTML; it does not measure Start HTTP/streaming overhead.
 
 ```bash
-TSR_LINK_PERF=1 CI=1 NX_DAEMON=false pnpm nx run @benchmarks/react-link-performance:test:perf:ssr --outputStyle=stream --skipRemoteCache -- --run
+CI=1 NX_DAEMON=false pnpm nx run @benchmarks/react-link-performance:test:perf:ssr --outputStyle=stream --skipRemoteCache -- --run
 ```
 
 These cases are excluded from this directory's aggregate projects and normal
-CodSpeed dependency graph. The flag must be explicitly enabled when invoking
-the dedicated target.
+CodSpeed dependency graph; they only run through the dedicated target above.

packages/router-core/src/path.ts

@@ -218,6 +218,11 @@ export function getRouteSegments(route: AnyRoute) {
   return route._interpolation
 }
 
+/** A splat is missing when it has no value; `0` and `false` are stringified like any other param. */
+function isMissingSplat(value: unknown): boolean {
+  return value == null || value === ''
+}
+
 /** Devtools checks navigation availability separately from the hot formatter. */
 export function hasMissingPathParams(
   segments: RouteInterpolation,
@@ -229,7 +234,7 @@ export function hasMissingPathParams(
     }
     const [kind, key] = part
     return kind === SEGMENT_TYPE_WILDCARD
-      ? !params[key]
+      ? isMissingSplat(params[key])
       : kind === SEGMENT_TYPE_PARAM && !(key in params)
   })
 }
@@ -290,7 +295,7 @@ export function interpolatePath(
         usedParams['*'] = paramValue
       }
     }
-    if (splat && !paramValue) {
+    if (splat && isMissingSplat(paramValue)) {
       // A missing wildcard keeps its affixes, but omits a bare segment.
       if (prefix === '/' && !suffix) {
         continue

packages/router-core/tests/lightweight-location.bench.ts

@@ -3,62 +3,57 @@ import { createMemoryHistory } from '@tanstack/history'
 import { BaseRootRoute, BaseRoute } from '../src'
 import { createTestRouter } from './routerTestUtils'
 
-if (process.env.TSR_LINK_PERF === '1') {
-  describe.each([false, true])(
-    'cold lightweight locations (server: %s)',
-    (isServer) => {
-      for (const count of [1, 8, 32]) {
-        const root = new BaseRootRoute({})
-        const segments = Array.from(
-          { length: count },
-          (_, index) => `$p${index}`,
-        )
-        const source = new BaseRoute({
-          getParentRoute: () => root,
-          path: `/source/${segments.join('/')}`,
-        })
-        const target = new BaseRoute({
-          getParentRoute: () => root,
-          path: '/target',
-        })
-        const history = createMemoryHistory({ initialEntries: ['/'] })
-        const router = createTestRouter({
-          routeTree: root.addChildren([source, target]),
-          history,
-          isServer,
-          scrollRestoration: false,
-        })
-        history.destroy()
-        const pathname = `/source/${segments.map((_, index) => String(index)).join('/')}`
-        const location = {
-          ...router.latestLocation,
-          pathname,
-          href: pathname,
-          publicHref: pathname,
-        }
-        let checksum = 0
-        const iterations = 256
-        function run() {
-          checksum = 0
-          for (let index = 0; index < iterations; index++) {
-            checksum += router.buildLocation({
-              to: '/target',
-              params: true,
-              _fromLocation: { ...location },
-            }).pathname.length
-          }
+describe.each([false, true])(
+  'cold lightweight locations (server: %s)',
+  (isServer) => {
+    for (const count of [1, 8, 32]) {
+      const root = new BaseRootRoute({})
+      const segments = Array.from({ length: count }, (_, index) => `$p${index}`)
+      const source = new BaseRoute({
+        getParentRoute: () => root,
+        path: `/source/${segments.join('/')}`,
+      })
+      const target = new BaseRoute({
+        getParentRoute: () => root,
+        path: '/target',
+      })
+      const history = createMemoryHistory({ initialEntries: ['/'] })
+      const router = createTestRouter({
+        routeTree: root.addChildren([source, target]),
+        history,
+        isServer,
+        scrollRestoration: false,
+      })
+      history.destroy()
+      const pathname = `/source/${segments.map((_, index) => String(index)).join('/')}`
+      const location = {
+        ...router.latestLocation,
+        pathname,
+        href: pathname,
+        publicHref: pathname,
+      }
+      let checksum = 0
+      const iterations = 256
+      function run() {
+        checksum = 0
+        for (let index = 0; index < iterations; index++) {
+          checksum += router.buildLocation({
+            to: '/target',
+            params: true,
+            _fromLocation: { ...location },
+          }).pathname.length
         }
-        run()
-        expect(checksum).toBe(iterations * '/target'.length)
-        bench(`${count} source params`, run, {
-          time: 1000,
-          warmupTime: 200,
-          throws: true,
-          teardown: () => {
-            expect(checksum).toBe(iterations * '/target'.length)
-          },
-        })
       }
-    },
-  )
-}
+      run()
+      expect(checksum).toBe(iterations * '/target'.length)
+      bench(`${count} source params`, run, {
+        time: 1000,
+        warmupTime: 200,
+        throws: true,
+        teardown: () => {
+          expect(checksum).toBe(iterations * '/target'.length)
+        },
+      })
+    }
+  },
+)