test(react-router): add React 19 test variant for multi-version CI coverage, verified known react 19 issue is caught by it

Author: ShaneK

.github/workflows/build.yml

@@ -176,7 +176,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        apps: [reactrouter6]
+        apps: [reactrouter6-react18, reactrouter6-react19]
     needs: [build-react, build-react-router]
     runs-on: ubuntu-latest
     steps:

.github/workflows/stencil-nightly.yml

@@ -186,7 +186,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        apps: [reactrouter6]
+        apps: [reactrouter6-react18, reactrouter6-react19]
     needs: [build-react, build-react-router]
     runs-on: ubuntu-latest
     steps:

packages/react-router/scripts/test_runner.sh

@@ -10,10 +10,12 @@ cd "$SCRIPT_DIR"
 #   --skip-build         Skip all build steps (reuse existing build artifacts)
 #   --playwright-only    Skip Cypress, run only Playwright
 #   --spec <pattern>     Filter Playwright tests by file path pattern
+#   --app <name>         Test app variant (default: reactrouter6-react18)
 # ---------------------------------------------------------------------------
 SKIP_BUILD=0
 PLAYWRIGHT_ONLY=0
 PLAYWRIGHT_SPEC=""
+APP_NAME="reactrouter6-react18"
 
 while [[ $# -gt 0 ]]; do
   case "$1" in
@@ -33,9 +35,17 @@ while [[ $# -gt 0 ]]; do
       PLAYWRIGHT_SPEC="$2"
       shift 2
       ;;
+    --app)
+      if [[ -z "$2" || "$2" == --* ]]; then
+        echo "Error: --app requires a value"
+        exit 1
+      fi
+      APP_NAME="$2"
+      shift 2
+      ;;
     *)
       echo "Unknown flag: $1"
-      echo "Usage: $0 [--skip-build] [--playwright-only] [--spec <pattern>]"
+      echo "Usage: $0 [--skip-build] [--playwright-only] [--spec <pattern>] [--app <name>]"
       exit 1
       ;;
   esac
@@ -62,17 +72,17 @@ if [ "$SKIP_BUILD" = "0" ]; then
   npm run build
 
   # Inside packages/react-router/test
-  echo "Building test app..."
+  echo "Building test app ($APP_NAME)..."
   cd ./test
-  rm -rf build/reactrouter6 || true
-  sh ./build.sh reactrouter6
-  cd build/reactrouter6
+  rm -rf "build/$APP_NAME" || true
+  sh ./build.sh "$APP_NAME"
+  cd "build/$APP_NAME"
   echo "Installing dependencies..."
   npm install --legacy-peer-deps > npm_install.log 2>&1
   npm run sync
 else
   echo "Skipping build (--skip-build)."
-  cd ../test/build/reactrouter6
+  cd "../test/build/$APP_NAME"
 fi
 
 # Install Playwright browsers if not already present

…test/apps/reactrouter6/package-lock.json …s/reactrouter6-react18/package-lock.jsonpackages/react-router/test/apps/reactrouter6/package-lock.json renamed to packages/react-router/test/apps/reactrouter6-react18/package-lock.json packages/react-router/test/apps/reactrouter6/package-lock.json renamed to packages/react-router/test/apps/reactrouter6-react18/package-lock.json

@@ -1,5 +1,5 @@
 {
-  "name": "react-router-new",
+  "name": "test-app",
   "version": "0.0.1",
   "private": true,
   "overrides": {
@@ -21,7 +21,7 @@
     "react-dom": "^18.2.0",
     "react-router": "^6.0.0",
     "react-router-dom": "^6.0.0",
-    "typescript": "^4.4.2"
+    "typescript": "^5.1.6"
   },
   "scripts": {
     "dev": "vite",