From 8d7f05e5336fa9a05c6ca5a610a0c5140c01bfc3 Mon Sep 17 00:00:00 2001
From: "J. David Lowe" <j.david.lowe@gmail.com>
Date: Thu, 23 Jan 2020 18:32:17 -0800
Subject: [PATCH] round-trip paramValues without exploding (#1463)

---
 bind_test.go           |  2 ++
 context.go             |  5 ++++-
 context_test.go        | 22 ++++++++++++++++++++++
 middleware/jwt_test.go |  2 ++
 4 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/bind_test.go b/bind_test.go
index b9fb9de3..943cfd55 100644
--- a/bind_test.go
+++ b/bind_test.go
@@ -332,6 +332,7 @@ func TestBindbindData(t *testing.T) {
 
 func TestBindParam(t *testing.T) {
 	e := New()
+	*e.maxParam = 2
 	req := httptest.NewRequest(GET, "/", nil)
 	rec := httptest.NewRecorder()
 	c := e.NewContext(req, rec)
@@ -362,6 +363,7 @@ func TestBindParam(t *testing.T) {
 	// Bind something with param and post data payload
 	body := bytes.NewBufferString(`{ "name": "Jon Snow" }`)
 	e2 := New()
+	*e2.maxParam = 2
 	req2 := httptest.NewRequest(POST, "/", body)
 	req2.Header.Set(HeaderContentType, MIMEApplicationJSON)
 
diff --git a/context.go b/context.go
index 27da5ffe..0046e5d4 100644
--- a/context.go
+++ b/context.go
@@ -312,7 +312,10 @@ func (c *context) ParamValues() []string {
 }
 
 func (c *context) SetParamValues(values ...string) {
-	c.pvalues = values
+	// NOTE: Don't just set c.pvalues = values, because it has to have length c.echo.maxParam at all times
+	for i, val := range values {
+		c.pvalues[i] = val
+	}
 }
 
 func (c *context) QueryParam(name string) string {
diff --git a/context_test.go b/context_test.go
index 47be19cc..bb4a9ed4 100644
--- a/context_test.go
+++ b/context_test.go
@@ -93,6 +93,7 @@ func (responseWriterErr) WriteHeader(statusCode int) {
 
 func TestContext(t *testing.T) {
 	e := New()
+	*e.maxParam = 1
 	req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(userJSON))
 	rec := httptest.NewRecorder()
 	c := e.NewContext(req, rec).(*context)
@@ -471,6 +472,7 @@ func TestContextPath(t *testing.T) {
 
 func TestContextPathParam(t *testing.T) {
 	e := New()
+	*e.maxParam = 2
 	req := httptest.NewRequest(http.MethodGet, "/", nil)
 	c := e.NewContext(req, nil)
 
@@ -487,6 +489,26 @@ func TestContextPathParam(t *testing.T) {
 	testify.Equal(t, "", c.Param("undefined"))
 }
 
+func TestContextGetAndSetParam(t *testing.T) {
+	e := New()
+	*e.maxParam = 2
+	req := httptest.NewRequest(http.MethodGet, "/:foo", nil)
+	c := e.NewContext(req, nil)
+	c.SetParamNames("foo")
+
+	// round-trip param values with modification
+	paramVals := c.ParamValues()
+	testify.EqualValues(t, []string{""}, c.ParamValues())
+	paramVals[0] = "bar"
+	c.SetParamValues(paramVals...)
+	testify.EqualValues(t, []string{"bar"}, c.ParamValues())
+
+	// shouldn't explode during Reset() afterwards!
+	testify.NotPanics(t, func() {
+		c.Reset(nil, nil)
+	})
+}
+
 func TestContextFormValue(t *testing.T) {
 	f := make(url.Values)
 	f.Set("name", "Jon Snow")
diff --git a/middleware/jwt_test.go b/middleware/jwt_test.go
index 7f15bd46..f7f089fb 100644
--- a/middleware/jwt_test.go
+++ b/middleware/jwt_test.go
@@ -60,6 +60,8 @@ func TestJWTRace(t *testing.T) {
 
 func TestJWT(t *testing.T) {
 	e := echo.New()
+	r := e.Router()
+	r.Add("GET", "/:jwt", func(echo.Context) error { return nil })
 	handler := func(c echo.Context) error {
 		return c.String(http.StatusOK, "test")
 	}