Quick Fix c.ClientIP() mistakely parsing to 127.0.0.1 for who not usi…

…ng r.Run() to run http server (gin-gonic#2832)

(cherry picked from commit 6d75aba)

gin.go

@@ -168,6 +168,7 @@ func New() *Engine {
 		trees:                  make(methodTrees, 0, 9),
 		delims:                 render.Delims{Left: "{{", Right: "}}"},
 		secureJSONPrefix:       "while(1);",
+		trustedCIDRs:           []*net.IPNet{{IP: net.IP{0x0, 0x0, 0x0, 0x0}, Mask: net.IPMask{0x0, 0x0, 0x0, 0x0}}},
 	}
 	engine.RouterGroup.engine = engine
 	engine.pool.New = func() interface{} {
@@ -249,9 +250,8 @@ func (engine *Engine) NoRoute(handlers ...HandlerFunc) {
 	engine.rebuild404Handlers()
 }
 
-// NoMethod sets the handlers called when NoMethod.
+// NoMethod sets the handlers called when Engine.HandleMethodNotAllowed = true.
 func (engine *Engine) NoMethod(handlers ...HandlerFunc) {
-	engine.HandleMethodNotAllowed = true
 	engine.noMethod = handlers
 	engine.rebuild405Handlers()
 }

middleware_test.go

@@ -118,7 +118,10 @@ func TestMiddlewareNoMethodEnabled(t *testing.T) {
 func TestMiddlewareNoMethodDisabled(t *testing.T) {
 	signature := ""
 	router := New()
+
+	// NoMethod disabled
 	router.HandleMethodNotAllowed = false
+
 	router.Use(func(c *Context) {
 		signature += "A"
 		c.Next()
@@ -144,6 +147,7 @@ func TestMiddlewareNoMethodDisabled(t *testing.T) {
 	router.POST("/", func(c *Context) {
 		signature += " XX "
 	})
+
 	// RUN
 	w := performRequest(router, "GET", "/")