c.ClientIP() is incorrect under goroutine

[leeqvip]

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Description

c.ClientIP() is incorrect under goroutine

How to reproduce

func Handler(c *gin.Context){
    ip1 := c.ClientIP()
    go func(ip1 string) {
        ip2 := c.ClientIP()
        fmt.Println(ip1, ip2) // Under high concurrency, the two are not equal
    }(ip1)

        c.JSON(200, nil)
}

Expectations

fmt.Println(ip1, ip2) // Under high concurrency, the two are not equal

In most cases, the two are equal, but under high concurrency, the two are not equal, and the ip is rewritten by other requests

Actual result

Environment

• go version: 1.16
• gin version (or commit ref): v1.7.7
• operating system: centos 7

[eleven26]

You should pass context as first parameter to your goroutine，otherwise, you will get a different context in the goroutine, and the ip will naturally be different，that's what context exists for.

[timandy]

@leeqvip context is pooled object, pass context.Copy as first param.

func Handler(c *gin.Context) {
    ip1 := c.ClientIP()
    go func(cc *gin.Context) {
        ip2 := cc.ClientIP()
        fmt.Println(ip1, ip2)
    }(c.Copy())

    c.JSON(200, nil)
}