How Can I Handle Deferred Functions with Returned Variables in Go without Errors?

gometalinter / errcheck and Deferred Functions with Returned Variables

gometalinter and errcheck tools raise a warning when a function that returns a variable is deferred. This occurs because deferred functions' return values are discarded, so the returned error variable is not checked.

The recommended approach is to defer another function that calls the original function and handles its return value. This can be done using an anonymous function as follows:

<code class="go">defer func() {
    if err := r.Body.Close(); err != nil {
        fmt.Println("Error when closing:", err)
    }
}()</code>

Alternatively, you can create a helper function to handle error checking:

<code class="go">func Check(f func() error) {
    if err := f(); err != nil {
        fmt.Println("Received error:", err)
    }
}</code>

Usage:

<code class="go">defer Check(r.Body.Close)</code>

For multiple deferred functions, consider a helper function that takes multiple functions:

<code class="go">func Checks(fs ...func() error) {
    for i := len(fs) - 1; i >= 0; i-- {
        if err := fs[i](); err != nil {
            fmt.Println("Received error:", err)
        }
    }
}</code>

Usage:

<code class="go">defer Checks(r.Body.Close, SomeOtherFunc)</code>

Note that the downward loop in Checks() mimics the execution order of deferred functions (last-in-first-out).

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