Proper colon support in reverse (#2416)

* Adds support of the escaped colon in echo.Reverse --------- Co-authored-by: Mihard <mihard@webird.ru>

Author: mihard

echo_test.go

@@ -1517,26 +1517,97 @@ func TestEcho_OnAddRouteHandler(t *testing.T) {
 }
 
 func TestEchoReverse(t *testing.T) {
-e := New()
-dummyHandler := func(Context) error { return nil }
+var testCases = []struct {
+name string
+whenRouteName string
+whenParams []interface{}
+expect string
+}{
+{
+name: "ok,static with no params",
+whenRouteName: "/static",
+expect: "/static",
+},
+{
+name: "ok,static with non existent param",
+whenRouteName: "/static",
+whenParams: []interface{}{"missing param"},
+expect: "/static",
+},
+{
+name: "ok, wildcard with no params",
+whenRouteName: "/static/*",
+expect: "/static/*",
+},
+{
+name: "ok, wildcard with params",
+whenRouteName: "/static/*",
+whenParams: []interface{}{"foo.txt"},
+expect: "/static/foo.txt",
+},
+{
+name: "ok, single param without param",
+whenRouteName: "/params/:foo",
+expect: "/params/:foo",
+},
+{
+name: "ok, single param with param",
+whenRouteName: "/params/:foo",
+whenParams: []interface{}{"one"},
+expect: "/params/one",
+},
+{
+name: "ok, multi param without params",
+whenRouteName: "/params/:foo/bar/:qux",
+expect: "/params/:foo/bar/:qux",
+},
+{
+name: "ok, multi param with one param",
+whenRouteName: "/params/:foo/bar/:qux",
+whenParams: []interface{}{"one"},
+expect: "/params/one/bar/:qux",
+},
+{
+name: "ok, multi param with all params",
+whenRouteName: "/params/:foo/bar/:qux",
+whenParams: []interface{}{"one", "two"},
+expect: "/params/one/bar/two",
+},
+{
+name: "ok, multi param + wildcard with all params",
+whenRouteName: "/params/:foo/bar/:qux/*",
+whenParams: []interface{}{"one", "two", "three"},
+expect: "/params/one/bar/two/three",
+},
+{
+name: "ok, backslash is not escaped",
+whenRouteName: "/backslash",
+whenParams: []interface{}{"test"},
+expect: `/a\b/test`,
+},
+{
+name: "ok, escaped colon verbs",
+whenRouteName: "/params:customVerb",
+whenParams: []interface{}{"PATCH"},
+expect: `/params:PATCH`,
+},
+}
+for _, tc := range testCases {
+t.Run(tc.name, func(t *testing.T) {
+e := New()
+dummyHandler := func(Context) error { return nil }
+
+e.GET("/static", dummyHandler).Name = "/static"
+e.GET("/static/*", dummyHandler).Name = "/static/*"
+e.GET("/params/:foo", dummyHandler).Name = "/params/:foo"
+e.GET("/params/:foo/bar/:qux", dummyHandler).Name = "/params/:foo/bar/:qux"
+e.GET("/params/:foo/bar/:qux/*", dummyHandler).Name = "/params/:foo/bar/:qux/*"
+e.GET("/a\\b/:x", dummyHandler).Name = "/backslash"
+e.GET("/params\\::customVerb", dummyHandler).Name = "/params:customVerb"
 
-e.GET("/static", dummyHandler).Name = "/static"
-e.GET("/static/*", dummyHandler).Name = "/static/*"
-e.GET("/params/:foo", dummyHandler).Name = "/params/:foo"
-e.GET("/params/:foo/bar/:qux", dummyHandler).Name = "/params/:foo/bar/:qux"
-e.GET("/params/:foo/bar/:qux/*", dummyHandler).Name = "/params/:foo/bar/:qux/*"
-
-assert.Equal(t, "/static", e.Reverse("/static"))
-assert.Equal(t, "/static", e.Reverse("/static", "missing param"))
-assert.Equal(t, "/static/*", e.Reverse("/static/*"))
-assert.Equal(t, "/static/foo.txt", e.Reverse("/static/*", "foo.txt"))
-
-assert.Equal(t, "/params/:foo", e.Reverse("/params/:foo"))
-assert.Equal(t, "/params/one", e.Reverse("/params/:foo", "one"))
-assert.Equal(t, "/params/:foo/bar/:qux", e.Reverse("/params/:foo/bar/:qux"))
-assert.Equal(t, "/params/one/bar/:qux", e.Reverse("/params/:foo/bar/:qux", "one"))
-assert.Equal(t, "/params/one/bar/two", e.Reverse("/params/:foo/bar/:qux", "one", "two"))
-assert.Equal(t, "/params/one/bar/two/three", e.Reverse("/params/:foo/bar/:qux/*", "one", "two", "three"))
+assert.Equal(t, tc.expect, e.Reverse(tc.whenRouteName, tc.whenParams...))
+})
+}
 }
 
 func TestEchoReverseHandleHostProperly(t *testing.T) {

router.go

@@ -159,7 +159,12 @@ func (r *Router) Reverse(name string, params ...interface{}) string {
 for _, route := range r.routes {
 if route.Name == name {
 for i, l := 0, len(route.Path); i < l; i++ {
-if (route.Path[i] == ':' || route.Path[i] == '*') && n < ln {
+hasBackslash := route.Path[i] == '\\'
+if hasBackslash && i+1 < l && route.Path[i+1] == ':' {
+i++ // backslash before colon escapes that colon. in that case skip backslash
+}
+if n < ln && (route.Path[i] == '*' || (!hasBackslash && route.Path[i] == ':')) {
+// in case of `*` wildcard or `:` (unescaped colon) param we replace everything till next slash or end of path
 for ; i < l && route.Path[i] != '/'; i++ {
 }
 uri.WriteString(fmt.Sprintf("%v", params[n]))