Fix conflict between param and exact path (#2706)

* Fix conflict between param and exact path

Signed-off-by: Yue Yang <g1enyy0ung@gmail.com>

* Add test

Signed-off-by: Yue Yang <g1enyy0ung@gmail.com>

* Fix prefix conflict in exact paths

Signed-off-by: Yue Yang <g1enyy0ung@gmail.com>

* Use backtracking

Signed-off-by: Yue Yang <g1enyy0ung@gmail.com>

* Fix panic

Signed-off-by: Yue Yang <g1enyy0ung@gmail.com>

tree.go

@@ -118,6 +118,11 @@ type node struct {
 	fullPath  string
 }
 
+type skip struct {
+	path      string
+	paramNode *node
+}
+
 // Increments priority of the given child and reorders if necessary
 func (n *node) incrementChildPrio(pos int) int {
 	cs := n.children
@@ -400,6 +405,8 @@ type nodeValue struct {
 // made if a handle exists with an extra (without the) trailing slash for the
 // given path.
 func (n *node) getValue(path string, params *Params, unescape bool) (value nodeValue) {
+	var skipped *skip
+
 walk: // Outer loop for walking the tree
 	for {
 		prefix := n.path
@@ -411,6 +418,21 @@ walk: // Outer loop for walking the tree
 				idxc := path[0]
 				for i, c := range []byte(n.indices) {
 					if c == idxc {
+						if strings.HasPrefix(n.children[len(n.children)-1].path, ":") {
+							skipped = &skip{
+								path: prefix + path,
+								paramNode: &node{
+									path:      n.path,
+									wildChild: n.wildChild,
+									nType:     n.nType,
+									priority:  n.priority,
+									children:  n.children,
+									handlers:  n.handlers,
+									fullPath:  n.fullPath,
+								},
+							}
+						}
+
 						n = n.children[i]
 						continue walk
 					}
@@ -542,6 +564,13 @@ walk: // Outer loop for walking the tree
 			return
 		}
 
+		if path != "/" && skipped != nil && strings.HasSuffix(skipped.path, path) {
+			path = skipped.path
+			n = skipped.paramNode
+			skipped = nil
+			continue walk
+		}
+
 		// Nothing found. We can recommend to redirect to the same URL with an
 		// extra trailing slash if a leaf exists for that path
 		value.tsr = (path == "/") ||

tree_test.go

@@ -135,13 +135,16 @@ func TestTreeWildcard(t *testing.T) {
 
 	routes := [...]string{
 		"/",
-		"/cmd/:tool/:sub",
 		"/cmd/:tool/",
+		"/cmd/:tool/:sub",
 		"/cmd/whoami",
+		"/cmd/whoami/root",
 		"/cmd/whoami/root/",
 		"/src/*filepath",
 		"/search/",
 		"/search/:query",
+		"/search/gin-gonic",
+		"/search/google",
 		"/user_:name",
 		"/user_:name/about",
 		"/files/:dir/*filepath",
@@ -150,6 +153,7 @@ func TestTreeWildcard(t *testing.T) {
 		"/doc/go1.html",
 		"/info/:user/public",
 		"/info/:user/project/:project",
+		"/info/:user/project/golang",
 	}
 	for _, route := range routes {
 		tree.addRoute(route, fakeHandler(route))
@@ -159,21 +163,29 @@ func TestTreeWildcard(t *testing.T) {
 		{"/", false, "/", nil},
 		{"/cmd/test", true, "/cmd/:tool/", Params{Param{"tool", "test"}}},
 		{"/cmd/test/", false, "/cmd/:tool/", Params{Param{"tool", "test"}}},
+		{"/cmd/test/3", false, "/cmd/:tool/:sub", Params{Param{Key: "tool", Value: "test"}, Param{Key: "sub", Value: "3"}}},
+		{"/cmd/who", true, "/cmd/:tool/", Params{Param{"tool", "who"}}},
+		{"/cmd/who/", false, "/cmd/:tool/", Params{Param{"tool", "who"}}},
 		{"/cmd/whoami", false, "/cmd/whoami", nil},
 		{"/cmd/whoami/", true, "/cmd/whoami", nil},
+		{"/cmd/whoami/r", false, "/cmd/:tool/:sub", Params{Param{Key: "tool", Value: "whoami"}, Param{Key: "sub", Value: "r"}}},
+		{"/cmd/whoami/r/", true, "/cmd/:tool/:sub", Params{Param{Key: "tool", Value: "whoami"}, Param{Key: "sub", Value: "r"}}},
+		{"/cmd/whoami/root", false, "/cmd/whoami/root", nil},
 		{"/cmd/whoami/root/", false, "/cmd/whoami/root/", nil},
-		{"/cmd/whoami/root", true, "/cmd/whoami/root/", nil},
-		{"/cmd/test/3", false, "/cmd/:tool/:sub", Params{Param{Key: "tool", Value: "test"}, Param{Key: "sub", Value: "3"}}},
 		{"/src/", false, "/src/*filepath", Params{Param{Key: "filepath", Value: "/"}}},
 		{"/src/some/file.png", false, "/src/*filepath", Params{Param{Key: "filepath", Value: "/some/file.png"}}},
 		{"/search/", false, "/search/", nil},
 		{"/search/someth!ng+in+ünìcodé", false, "/search/:query", Params{Param{Key: "query", Value: "someth!ng+in+ünìcodé"}}},
 		{"/search/someth!ng+in+ünìcodé/", true, "", Params{Param{Key: "query", Value: "someth!ng+in+ünìcodé"}}},
+		{"/search/gin", false, "/search/:query", Params{Param{"query", "gin"}}},
+		{"/search/gin-gonic", false, "/search/gin-gonic", nil},
+		{"/search/google", false, "/search/google", nil},
 		{"/user_gopher", false, "/user_:name", Params{Param{Key: "name", Value: "gopher"}}},
 		{"/user_gopher/about", false, "/user_:name/about", Params{Param{Key: "name", Value: "gopher"}}},
 		{"/files/js/inc/framework.js", false, "/files/:dir/*filepath", Params{Param{Key: "dir", Value: "js"}, Param{Key: "filepath", Value: "/inc/framework.js"}}},
 		{"/info/gordon/public", false, "/info/:user/public", Params{Param{Key: "user", Value: "gordon"}}},
 		{"/info/gordon/project/go", false, "/info/:user/project/:project", Params{Param{Key: "user", Value: "gordon"}, Param{Key: "project", Value: "go"}}},
+		{"/info/gordon/project/golang", false, "/info/:user/project/golang", Params{Param{Key: "user", Value: "gordon"}}},
 	})
 
 	checkPriorities(t, tree)