fix: hertz panic when edit ctx.Params on HandleFunc

pkg/app/context.go

@@ -203,11 +203,12 @@ type RequestContext struct {
 	// Errors is a list of errors attached to all the handlers/middlewares who used this context.
 	Errors errors.ErrorChain
 
-	Params     param.Params
-	handlers   HandlersChain
-	fullPath   string
-	index      int8
-	HTMLRender render.HTMLRender
+	Params      param.Params
+	paramsCount int
+	handlers    HandlersChain
+	fullPath    string
+	index       int8
+	HTMLRender  render.HTMLRender
 
 	// This mutex protect Keys map.
 	mu sync.RWMutex
@@ -298,7 +299,7 @@ func (ctx *RequestContext) SetEnableTrace(enable bool) {
 // Set the Request filed before use it for handlers
 func NewContext(maxParams uint16) *RequestContext {
 	v := make(param.Params, 0, maxParams)
-	ctx := &RequestContext{Params: v, index: -1}
+	ctx := &RequestContext{Params: v, index: -1, paramsCount: int(maxParams)}
 	return ctx
 }
 
@@ -845,6 +846,10 @@ func (ctx *RequestContext) HandlerName() string {
 	return utils.NameOfFunction(ctx.handlers.Last())
 }
 
+func (ctx *RequestContext) GetParamsCount() int {
+	return ctx.paramsCount
+}
+
 func (ctx *RequestContext) ResetWithoutConn() {
 	ctx.Params = ctx.Params[0:0]
 	ctx.Errors = ctx.Errors[0:0]

pkg/route/engine.go

@@ -75,6 +75,7 @@ import (
 	"github.com/cloudwego/hertz/pkg/protocol/http1"
 	"github.com/cloudwego/hertz/pkg/protocol/http1/factory"
 	"github.com/cloudwego/hertz/pkg/protocol/suite"
+	"github.com/cloudwego/hertz/pkg/route/param"
 )
 
 const unknownTransporterName = "unknown"
@@ -749,6 +750,11 @@ func (engine *Engine) ServeHTTP(c context.Context, ctx *app.RequestContext) {
 		return
 	}
 
+	// if ctx.Params is re-assigned by user in HandlerFunc and the capacity changed we need to realloc
+	if cap(ctx.Params) < ctx.GetParamsCount() {
+		ctx.Params = make(param.Params, ctx.GetParamsCount())
+	}
+
 	// Find root of the tree for the given HTTP method
 	t := engine.trees
 	paramsPointer := &ctx.Params

pkg/route/engine_test.go

@@ -1029,3 +1029,33 @@ func TestAcquireHijackConn(t *testing.T) {
 	assert.DeepEqual(t, engine, hijackConn.e)
 	assert.DeepEqual(t, conn, hijackConn.Conn)
 }
+
+func TestHandleParamsReassignInHandleFunc(t *testing.T) {
+	e := NewEngine(config.NewOptions(nil))
+	routes := []string{
+		"/:a/:b/:c",
+	}
+	for _, r := range routes {
+		e.GET(r, func(c context.Context, ctx *app.RequestContext) {
+			ctx.Params = make([]param.Param, 1)
+			ctx.String(consts.StatusOK, "")
+		})
+	}
+	testRoutes := []string{
+		"/aaa/bbb/ccc",
+		"/asd/alskja/alkdjad",
+		"/asd/alskja/alkdjad",
+		"/asd/alskja/alkdjad",
+		"/asd/alskja/alkdjad",
+		"/alksjdlakjd/ooo/askda",
+		"/alksjdlakjd/ooo/askda",
+		"/alksjdlakjd/ooo/askda",
+	}
+	ctx := e.ctxPool.Get().(*app.RequestContext)
+	for _, tr := range testRoutes {
+		r := protocol.NewRequest(http.MethodGet, tr, nil)
+		r.CopyTo(&ctx.Request)
+		e.ServeHTTP(context.Background(), ctx)
+		ctx.ResetWithoutConn()
+	}
+}