Merge bf0836cc3a34af65b42744d2bc39d65df878ae41 into 5fad976b372e381312f8de69f0969f1284d229d3

* fix: call updateRouteTrees in ServeHTTP using sync.Once to support literal colon routes in all usage scenarios (#4413)

* chore: fixed golangci-lint issue in test cases for literal colon

* fix: gofumpt formatting issue

* fix: gofumpt issue in gin.go

* chore: updated routeTreesUpdated comments

* chore: removed unused variable and updated TestUpdateRouteTreesCalledOnce testcase

* chore: moved tests from literal_colon_test.go into gin_test.go

---------

Co-authored-by: pawannn <pawan@zenz.tech>

debug.go

@@ -13,7 +13,9 @@ import (
 	"sync/atomic"
 )
 
-const ginSupportMinGoVer = 23
+const ginSupportMinGoVer = 24
+
+var runtimeVersion = runtime.Version()
 
 // IsDebugging returns true if the framework is running in debug mode.
 // Use SetMode(gin.ReleaseMode) to disable debug mode.
@@ -77,7 +79,7 @@ func getMinVer(v string) (uint64, error) {
 }
 
 func debugPrintWARNINGDefault() {
-	if v, e := getMinVer(runtime.Version()); e == nil && v < ginSupportMinGoVer {
+	if v, e := getMinVer(runtimeVersion); e == nil && v < ginSupportMinGoVer {
 		debugPrint(`[WARNING] Now Gin requires Go 1.24+.
 
 `)

debug_test.go

@@ -12,7 +12,6 @@ import (
 	"log"
 	"net/http"
 	"os"
-	"runtime"
 	"strings"
 	"sync"
 	"testing"
@@ -21,10 +20,6 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// TODO
-// func debugRoute(httpMethod, absolutePath string, handlers HandlersChain) {
-// func debugPrint(format string, values ...any) {
-
 func TestIsDebugging(t *testing.T) {
 	SetMode(DebugMode)
 	assert.True(t, IsDebugging())
@@ -48,6 +43,18 @@ func TestDebugPrint(t *testing.T) {
 	assert.Equal(t, "[GIN-debug] these are 2 error messages\n", re)
 }
 
+func TestDebugPrintFunc(t *testing.T) {
+	DebugPrintFunc = func(format string, values ...any) {
+		fmt.Fprintf(DefaultWriter, "[GIN-debug] "+format, values...)
+	}
+	re := captureOutput(t, func() {
+		SetMode(DebugMode)
+		debugPrint("debug print func test: %d", 123)
+		SetMode(TestMode)
+	})
+	assert.Regexp(t, `^\[GIN-debug\] debug print func test: 123`, re)
+}
+
 func TestDebugPrintError(t *testing.T) {
 	re := captureOutput(t, func() {
 		SetMode(DebugMode)
@@ -104,12 +111,17 @@ func TestDebugPrintWARNINGDefault(t *testing.T) {
 		debugPrintWARNINGDefault()
 		SetMode(TestMode)
 	})
-	m, e := getMinVer(runtime.Version())
-	if e == nil && m < ginSupportMinGoVer {
-		assert.Equal(t, "[GIN-debug] [WARNING] Now Gin requires Go 1.24+.\n\n[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.\n\n", re)
-	} else {
-		assert.Equal(t, "[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.\n\n", re)
-	}
+	assert.Equal(t, "[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.\n\n", re)
+}
+
+func TestDebugPrintWARNINGDefaultWithUnsupportedVersion(t *testing.T) {
+	runtimeVersion = "go1.23.12"
+	re := captureOutput(t, func() {
+		SetMode(DebugMode)
+		debugPrintWARNINGDefault()
+		SetMode(TestMode)
+	})
+	assert.Equal(t, "[GIN-debug] [WARNING] Now Gin requires Go 1.24+.\n\n[GIN-debug] [WARNING] Creating an Engine instance with the Logger and Recovery middleware already attached.\n\n", re)
 }
 
 func TestDebugPrintWARNINGNew(t *testing.T) {

gin.go

@@ -98,6 +98,10 @@ const (
 type Engine struct {
 	RouterGroup
 
+	// routeTreesUpdated ensures that the initialization or update of the route trees
+	// (used for routing HTTP requests) happens only once, even if called multiple times concurrently.
+	routeTreesUpdated sync.Once
+
 	// RedirectTrailingSlash enables automatic redirection if the current route can't be matched but a
 	// handler for the path with (without) the trailing slash exists.
 	// For example if /foo/ is requested but a route only exists for /foo, the
@@ -654,6 +658,10 @@ func (engine *Engine) RunListener(listener net.Listener) (err error) {
 
 // ServeHTTP conforms to the http.Handler interface.
 func (engine *Engine) ServeHTTP(w http.ResponseWriter, req *http.Request) {
+	engine.routeTreesUpdated.Do(func() {
+		engine.updateRouteTrees()
+	})
+
 	c := engine.pool.Get().(*Context)
 	c.writermem.reset(w)
 	c.Request = req

gin_test.go

@@ -913,3 +913,102 @@ func TestMethodNotAllowedNoRoute(t *testing.T) {
 	assert.NotPanics(t, func() { g.ServeHTTP(resp, req) })
 	assert.Equal(t, http.StatusNotFound, resp.Code)
 }
+
+// Test the fix for https://github.com/gin-gonic/gin/pull/4415
+func TestLiteralColonWithRun(t *testing.T) {
+	SetMode(TestMode)
+	router := New()
+
+	router.GET(`/test\:action`, func(c *Context) {
+		c.JSON(http.StatusOK, H{"path": "literal_colon"})
+	})
+
+	router.updateRouteTrees()
+
+	w := httptest.NewRecorder()
+
+	req, _ := http.NewRequest(http.MethodGet, "/test:action", nil)
+	router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Contains(t, w.Body.String(), "literal_colon")
+}
+
+func TestLiteralColonWithDirectServeHTTP(t *testing.T) {
+	SetMode(TestMode)
+	router := New()
+
+	router.GET(`/test\:action`, func(c *Context) {
+		c.JSON(http.StatusOK, H{"path": "literal_colon"})
+	})
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodGet, "/test:action", nil)
+	router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Contains(t, w.Body.String(), "literal_colon")
+}
+
+func TestLiteralColonWithHandler(t *testing.T) {
+	SetMode(TestMode)
+	router := New()
+
+	router.GET(`/test\:action`, func(c *Context) {
+		c.JSON(http.StatusOK, H{"path": "literal_colon"})
+	})
+
+	handler := router.Handler()
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodGet, "/test:action", nil)
+	handler.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Contains(t, w.Body.String(), "literal_colon")
+}
+
+func TestLiteralColonWithHTTPServer(t *testing.T) {
+	SetMode(TestMode)
+	router := New()
+
+	router.GET(`/test\:action`, func(c *Context) {
+		c.JSON(http.StatusOK, H{"path": "literal_colon"})
+	})
+
+	router.GET("/test/:param", func(c *Context) {
+		c.JSON(http.StatusOK, H{"param": c.Param("param")})
+	})
+
+	w := httptest.NewRecorder()
+	req, _ := http.NewRequest(http.MethodGet, "/test:action", nil)
+	router.ServeHTTP(w, req)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.Contains(t, w.Body.String(), "literal_colon")
+
+	w2 := httptest.NewRecorder()
+	req2, _ := http.NewRequest(http.MethodGet, "/test/foo", nil)
+	router.ServeHTTP(w2, req2)
+
+	assert.Equal(t, http.StatusOK, w2.Code)
+	assert.Contains(t, w2.Body.String(), "foo")
+}
+
+// Test that updateRouteTrees is called only once
+func TestUpdateRouteTreesCalledOnce(t *testing.T) {
+	SetMode(TestMode)
+	router := New()
+
+	router.GET(`/test\:action`, func(c *Context) {
+		c.String(http.StatusOK, "ok")
+	})
+
+	for range 5 {
+		w := httptest.NewRecorder()
+		req, _ := http.NewRequest(http.MethodGet, "/test:action", nil)
+		router.ServeHTTP(w, req)
+		assert.Equal(t, http.StatusOK, w.Code)
+		assert.Equal(t, "ok", w.Body.String())
+	}
+}