🐛 [Bug]: Client execFunc goroutine has no panic recovery — crash on fasthttp panic

[pageton]

Bug Description

The Fiber HTTP client's execFunc() goroutine has no recover(). If fasthttp.Do(), any hook, or CopyTo() panics, the entire process crashes. The channels are also never drained, causing the caller to hang or leak.

How to Reproduce

Steps to reproduce the behavior:

1. Use the Fiber client with a custom hook that panics
2. Call req.Send()
3. The panic propagates through the goroutine and crashes the server

Affected Code

client/core.go:80-136:

go func() {
    defer releaseErrChan(errChan)
    defer releaseResponseChan(respChan)
    // ... HTTP execution logic ...
    respChan <- resp  // never reached if panic occurs
}()

Expected Behavior

Add panic recovery that sends the error through the channel:

go func() {
    defer releaseErrChan(errChan)
    defer releaseResponseChan(respChan)
    defer func() {
        if r := recover(); r != nil {
            errChan <- fmt.Errorf("client panic: %v", r)
        }
    }()
    // ... existing logic ...
}()

Related

• 🐛 [Bug]: No panic recovery in defaultRequestHandler — one handler crash kills the server #4339 — No panic recovery in server handler (same class of bug)

Fiber Version

v3 (latest main branch)