Function looping router.go#Find

[art-frela]

Issue Description

Example code has the one registered route

e := echo.New()
// Routes
e.GET("/assets/:id", assetID)
...
// assetID mock of the real handler
func assetID(c echo.Context) error {
	return c.String(http.StatusOK, "assetID")
}

when request uri is /assets/tree/free application is looping...

if application is simple then another requests are processing, but in complex application it's don't answer to any requests and need kill -9 pid
current request deadlocking...

Checklist

• [ x] Dependencies installed
• [ x] No typos
• [ x] Searched existing issues and docs
  very similar issue#1461

Expected behaviour

404 {"message":"Not Found"}

Actual behaviour

curl  http://localhost:1323/assets/3/e
{"message":"Not Found"}

curl  http://localhost:1323/assets/tree/free
# looping and stop answer...

Steps to reproduce

• run code below
• make curl request curl http://localhost:1323/assets/tree/free

Working code to debug

package main

import (
	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
	"net/http"
)

func main() {
	// Echo instance
	e := echo.New()

	// Middleware
	e.Use(middleware.Logger())
	e.Use(middleware.Recover())

	// Routes
	e.GET("/assets/:id", assetID)
	// Start server
	e.Logger.Fatal(e.Start(":1323"))
}

// assetID mock of the real handler
func assetID(c echo.Context) error {
	return c.String(http.StatusOK, "assetID")
}

Version/commit

4.1.14

[art-frela]

in 4.1.13 doesn't has this problem

[rdluffy]

I have the same issue, it seems the problem comes with the addition of the following code in router.go (line 417):

else if cn != nil && strings.IndexByte(ns, '/') != 1 { // If slash is present, it means that this is a parameterized route. cn = cn.parent goto Param }

[lammel]

I hope to look into that this week, this is probably an unintentional loop caused by the backtracking in the path for parametrized routes as noted by @rdluffy

Our example should allow to reproduce that in the unit tests and fix the issue. Let's see if that is the case.

[lammel]

I tried to reproduce the issue in the router unit tests, but it is working there.
So back at debugging your example...

[lammel]

The issue was reproducable after all and a test was added for it.
A potential fix is provided with pull request #1501