feat: add basic race detector to detect invalid usage of the tree. (#44)

error.go

@@ -18,6 +18,7 @@ var (
 	ErrDiscardedResponseWriter = errors.New("discarded response writer")
 	ErrInvalidRedirectCode     = errors.New("invalid redirect code")
 	ErrNoClientIPStrategy      = errors.New("no client ip strategy")
+	ErrConcurrentAccess        = errors.New("concurrent access violation: multiple writes detected on tree")
 )
 
 // RouteConflictError is a custom error type used to represent conflicts when

fox_test.go

@@ -3196,6 +3196,58 @@ func TestDataRace(t *testing.T) {
 	wg.Wait()
 }
 
+func TestTree_RaceDetector(t *testing.T) {
+	var wg sync.WaitGroup
+	start, wait := atomicSync()
+	var raceCount atomic.Uint32
+
+	tree := New().Tree()
+
+	wg.Add(len(staticRoutes) * 3)
+	for _, rte := range staticRoutes {
+		go func() {
+			wait()
+			defer func() {
+				if v := recover(); v != nil {
+					raceCount.Add(1)
+					assert.ErrorIs(t, v.(error), ErrConcurrentAccess)
+				}
+				wg.Done()
+			}()
+			tree.insert(rte.method, rte.path, "", 0, &Route{path: rte.path})
+		}()
+
+		go func() {
+			wait()
+			defer func() {
+				if v := recover(); v != nil {
+					raceCount.Add(1)
+					assert.ErrorIs(t, v.(error), ErrConcurrentAccess)
+				}
+				wg.Done()
+			}()
+			tree.update(rte.method, rte.path, "", &Route{path: rte.path})
+		}()
+
+		go func() {
+			wait()
+			defer func() {
+				if v := recover(); v != nil {
+					raceCount.Add(1)
+					assert.ErrorIs(t, v.(error), ErrConcurrentAccess)
+				}
+				wg.Done()
+			}()
+			tree.remove(rte.method, rte.path, "")
+		}()
+	}
+
+	time.Sleep(500 * time.Millisecond)
+	start()
+	wg.Wait()
+	assert.GreaterOrEqual(t, raceCount.Load(), uint32(1))
+}
+
 func TestConcurrentRequestHandling(t *testing.T) {
 	r := New()
 

tree.go

@@ -38,6 +38,7 @@ type Tree struct {
 	sync.Mutex
 	maxParams atomic.Uint32
 	maxDepth  atomic.Uint32
+	race      atomic.Uint32
 }
 
 // Handle registers a new handler for the given method and path. On success, it returns the newly registered [Route].
@@ -220,6 +221,11 @@ func (t *Tree) Iter() Iter {
 // parseRoute before.
 func (t *Tree) insert(method, path, catchAllKey string, paramsN uint32, route *Route) error {
 	// Note that we need a consistent view of the tree during the patching so search must imperatively be locked.
+	if !t.race.CompareAndSwap(0, 1) {
+		panic(ErrConcurrentAccess)
+	}
+	defer t.race.Store(0)
+
 	var rootNode *node
 	nds := *t.nodes.Load()
 	index := findRootNode(method, nds)
@@ -394,6 +400,11 @@ func (t *Tree) insert(method, path, catchAllKey string, paramsN uint32, route *R
 // update is not safe for concurrent use.
 func (t *Tree) update(method string, path, catchAllKey string, route *Route) error {
 	// Note that we need a consistent view of the tree during the patching so search must imperatively be locked.
+	if !t.race.CompareAndSwap(0, 1) {
+		panic(ErrConcurrentAccess)
+	}
+	defer t.race.Store(0)
+
 	nds := *t.nodes.Load()
 	index := findRootNode(method, nds)
 	if index < 0 {
@@ -427,6 +438,12 @@ func (t *Tree) update(method string, path, catchAllKey string, route *Route) err
 
 // remove is not safe for concurrent use.
 func (t *Tree) remove(method, path, catchAllKey string) bool {
+	// Note that we need a consistent view of the tree during the patching so search must imperatively be locked.
+	if !t.race.CompareAndSwap(0, 1) {
+		panic(ErrConcurrentAccess)
+	}
+	defer t.race.Store(0)
+
 	nds := *t.nodes.Load()
 	index := findRootNode(method, nds)
 	if index < 0 {