From e207a3ce65323c3dda7cd8133fe14f4f1efd2500 Mon Sep 17 00:00:00 2001
From: Raphael Gavache <raphael.gavache@datadoghq.com>
Date: Tue, 26 Feb 2019 08:10:16 +0100
Subject: [PATCH] Fix context.Copy() race condition (#1020)

* Fix context.Copy race condition

* Update githubapi_test.go

* fix code format
---
 context.go        |  4 ++++
 context_test.go   |  2 ++
 githubapi_test.go | 23 +++++++++++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/context.go b/context.go
index fa63ec8ba2..7618cef5bd 100644
--- a/context.go
+++ b/context.go
@@ -82,6 +82,10 @@ func (c *Context) Copy() *Context {
 	cp.Writer = &cp.writermem
 	cp.index = abortIndex
 	cp.handlers = nil
+	cp.Keys = map[string]interface{}{}
+	for k, v := range c.Keys {
+		cp.Keys[k] = v
+	}
 	return &cp
 }
 
diff --git a/context_test.go b/context_test.go
index 34cc71a501..dc8ac30628 100644
--- a/context_test.go
+++ b/context_test.go
@@ -331,6 +331,8 @@ func TestContextCopy(t *testing.T) {
 	assert.Equal(t, cp.Keys, c.Keys)
 	assert.Equal(t, cp.engine, c.engine)
 	assert.Equal(t, cp.Params, c.Params)
+	cp.Set("foo", "notBar")
+	assert.False(t, cp.Keys["foo"] == c.Keys["foo"])
 }
 
 func TestContextHandlerName(t *testing.T) {
diff --git a/githubapi_test.go b/githubapi_test.go
index 29aa158478..fb74d65940 100644
--- a/githubapi_test.go
+++ b/githubapi_test.go
@@ -346,6 +346,29 @@ func TestBindUriError(t *testing.T) {
 	assert.Equal(t, http.StatusBadRequest, w1.Code)
 }
 
+func TestRaceContextCopy(t *testing.T) {
+	DefaultWriter = os.Stdout
+	router := Default()
+	router.GET("/test/copy/race", func(c *Context) {
+		c.Set("1", 0)
+		c.Set("2", 0)
+
+		// Sending a copy of the Context to two separate routines
+		go readWriteKeys(c.Copy())
+		go readWriteKeys(c.Copy())
+		c.String(http.StatusOK, "run OK, no panics")
+	})
+	w := performRequest(router, "GET", "/test/copy/race")
+	assert.Equal(t, "run OK, no panics", w.Body.String())
+}
+
+func readWriteKeys(c *Context) {
+	for {
+		c.Set("1", rand.Int())
+		c.Set("2", c.Value("1"))
+	}
+}
+
 func githubConfigRouter(router *Engine) {
 	for _, route := range githubAPI {
 		router.Handle(route.method, route.path, func(c *Context) {