Warns if response is attempted to be written twice

response.go

@@ -18,9 +18,18 @@ type Response struct {
 }
 
 // WriteHeader sets the status code for a response
-func (w *Response) WriteHeader(i int) {
-	w.Status = i
-	w.ResponseWriter.WriteHeader(i)
+func (w *Response) WriteHeader(code int) {
+	if code == w.Status {
+		return
+	}
+
+	if w.Status > 0 {
+		fmt.Printf("[WARNING] Headers were already written. Wanted to override status code %d with %d", w.Status, code)
+		return
+	}
+
+	w.Status = code
+	w.ResponseWriter.WriteHeader(code)
 }
 
 // Write the body of the response

response_test.go

@@ -0,0 +1,22 @@
+package buffalo
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_Response_MultipleWrite(t *testing.T) {
+	r := require.New(t)
+	resWr := httptest.NewRecorder()
+	res := Response{
+		ResponseWriter: resWr,
+	}
+
+	res.WriteHeader(http.StatusOK)
+	res.WriteHeader(http.StatusInternalServerError)
+
+	r.Equal(res.Status, http.StatusOK)
+}

runtime/version.go

@@ -1,4 +1,4 @@
 package runtime
 
 // Version is the current version of the buffalo binary
-var Version = "v0.16.16"
+var Version = "v0.16.17"