Stop useless panicking in context and render (#2150)

Co-authored-by: Bo-Yi Wu <appleboy.tw@gmail.com>

Author: eeonevision

context.go

@@ -924,7 +924,9 @@ func (c *Context) Render(code int, r render.Render) {
 	}
 
 	if err := r.Render(c.Writer); err != nil {
-		panic(err)
+		// Pushing error to c.Errors
+		_ = c.Error(err)
+		c.Abort()
 	}
 }
 

context_test.go

@@ -32,6 +32,8 @@ import (
 
 var _ context.Context = (*Context)(nil)
 
+var errTestRender = errors.New("TestRender")
+
 // Unit tests TODO
 // func (c *Context) File(filepath string) {
 // func (c *Context) Negotiate(code int, config Negotiate) {
@@ -643,25 +645,21 @@ func TestContextBodyAllowedForStatus(t *testing.T) {
 	assert.True(t, true, bodyAllowedForStatus(http.StatusInternalServerError))
 }
 
-type TestPanicRender struct{}
+type TestRender struct{}
 
-func (*TestPanicRender) Render(http.ResponseWriter) error {
-	return errors.New("TestPanicRender")
+func (*TestRender) Render(http.ResponseWriter) error {
+	return errTestRender
 }
 
-func (*TestPanicRender) WriteContentType(http.ResponseWriter) {}
+func (*TestRender) WriteContentType(http.ResponseWriter) {}
 
-func TestContextRenderPanicIfErr(t *testing.T) {
-	defer func() {
-		r := recover()
-		assert.Equal(t, "TestPanicRender", fmt.Sprint(r))
-	}()
+func TestContextRenderIfErr(t *testing.T) {
 	w := httptest.NewRecorder()
 	c, _ := CreateTestContext(w)
 
-	c.Render(http.StatusOK, &TestPanicRender{})
+	c.Render(http.StatusOK, &TestRender{})
 
-	assert.Fail(t, "Panic not detected")
+	assert.Equal(t, errorMsgs{&Error{Err: errTestRender, Type: 1}}, c.Errors)
 }
 
 // Tests that the response is serialized as JSON

render/json.go

@@ -53,11 +53,8 @@ var (
 )
 
 // Render (JSON) writes data with custom ContentType.
-func (r JSON) Render(w http.ResponseWriter) (err error) {
-	if err = WriteJSON(w, r.Data); err != nil {
-		panic(err)
-	}
-	return
+func (r JSON) Render(w http.ResponseWriter) error {
+	return WriteJSON(w, r.Data)
 }
 
 // WriteContentType (JSON) writes JSON ContentType.

render/render_test.go

@@ -40,12 +40,12 @@ func TestRenderJSON(t *testing.T) {
 	assert.Equal(t, "application/json; charset=utf-8", w.Header().Get("Content-Type"))
 }
 
-func TestRenderJSONPanics(t *testing.T) {
+func TestRenderJSONError(t *testing.T) {
 	w := httptest.NewRecorder()
 	data := make(chan int)
 
 	// json: unsupported type: chan int
-	assert.Panics(t, func() { assert.NoError(t, (JSON{data}).Render(w)) })
+	assert.Error(t, (JSON{data}).Render(w))
 }
 
 func TestRenderIndentedJSON(t *testing.T) {