fix(router-core): empty wilcard node is matched over sibling layout route (#5971)

Author: Sheraff

packages/router-core/src/new-process-route-tree.ts

@@ -1018,6 +1018,12 @@ function getNodeMatch<T extends RouteLike>(
     }
   }
 
+  if (bestMatch && wildcardMatch) {
+    return isFrameMoreSpecific(wildcardMatch, bestMatch)
+      ? bestMatch
+      : wildcardMatch
+  }
+
   if (bestMatch) return bestMatch
 
   if (wildcardMatch) return wildcardMatch

packages/router-core/tests/new-process-route-tree.test.ts

@@ -546,6 +546,30 @@ describe('findRouteMatch', () => {
       expect(res?.route.id).toBe('/a/b/$')
       expect(res?.params).toEqual({ _splat: 'foo', '*': 'foo' })
     })
+    describe('edge-case #5969: trailing empty wildcard should match', () => {
+      it('basic', () => {
+        const tree = makeTree(['/a/$'])
+        expect(findRouteMatch('/a/', tree)?.route.id).toBe('/a/$')
+        expect(findRouteMatch('/a', tree)?.route.id).toBe('/a/$')
+      })
+      it('with layout route', () => {
+        const tree = makeTree(['/a', '/a/$'])
+        expect(findRouteMatch('/a/', tree)?.route.id).toBe('/a/$')
+        expect(findRouteMatch('/a', tree)?.route.id).toBe('/a/$')
+      })
+      it('with index route (should not match)', () => {
+        const tree = makeTree(['/a/', '/a/$'])
+        expect(findRouteMatch('/a/', tree)?.route.id).toBe('/a/')
+        expect(findRouteMatch('/a', tree)?.route.id).toBe('/a/')
+      })
+      it('edge-case: deeper index route through skipped optional segments (should not match)', () => {
+        const tree = makeTree(['/{-$foo}/{-$bar}/a/', '/a/$'])
+        expect(findRouteMatch('/a/', tree)?.route.id).toBe(
+          '/{-$foo}/{-$bar}/a/',
+        )
+        expect(findRouteMatch('/a', tree)?.route.id).toBe('/{-$foo}/{-$bar}/a/')
+      })
+    })
   })
 
   describe('nested routes', () => {