panic when shutting down with SIGINT signal if proxy is enabled

[davidovich]

To reproduce:

• Start air with proxy enabled in config.
• Type CTRL-C

Result:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x8 pc=0x100e5b604]

goroutine 5074 [running]:
github.com/cosmtrek/air/runner.(*ProxyStream).RemoveSubscriber(0x14000236588, 0x9b)
        /Users/[user]/go/pkg/mod/github.com/cosmtrek/air@v1.52.0/runner/proxy_stream.go:42 +0xc4
github.com/cosmtrek/air/runner.(*Proxy).reloadHandler.func1()
        /Users/[user]/go/pkg/mod/github.com/cosmtrek/air@v1.52.0/runner/proxy.go:159 +0x84
created by github.com/cosmtrek/air/runner.(*Proxy).reloadHandler in goroutine 4997
        /Users/[user]/go/pkg/mod/github.com/cosmtrek/air@v1.52.0/runner/proxy.go:157 +0x2b8

A theory is that proxy.Stop() is called before the <- ctx.Done() channel yields, allowing making a call on an empty value of the map.

[ndajr]

Hi @davidovich, I am the author of the proxy feature. I am not able to reproduce this issue with the steps you mentioned. What is your OS and Go version? Does this happen when you start air for the first time with proxy enabled, or after a few reload events?

[ndajr]

Could you test please my branch fix-live-proxy? https://github.com/cosmtrek/air/compare/master...ndajr:air:fix-live-proxy?expand=1. I've improved the error handling, used atomic counters and RWMutex which should help to avoid race conditions

[xiantang]

Could you test please my branch fix-live-proxy? https://github.com/cosmtrek/air/compare/master...ndajr:air:fix-live-proxy?expand=1. I've improved the error handling, used atomic counters and RWMutex which should help to avoid race conditions

could u make a pr ?

[xiantang]

To reproduce:

• Start air with proxy enabled in config.
• Type CTRL-C

Result:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x2 addr=0x8 pc=0x100e5b604]

goroutine 5074 [running]:
github.com/cosmtrek/air/runner.(*ProxyStream).RemoveSubscriber(0x14000236588, 0x9b)
        /Users/[user]/go/pkg/mod/github.com/cosmtrek/air@v1.52.0/runner/proxy_stream.go:42 +0xc4
github.com/cosmtrek/air/runner.(*Proxy).reloadHandler.func1()
        /Users/[user]/go/pkg/mod/github.com/cosmtrek/air@v1.52.0/runner/proxy.go:159 +0x84
created by github.com/cosmtrek/air/runner.(*Proxy).reloadHandler in goroutine 4997
        /Users/[user]/go/pkg/mod/github.com/cosmtrek/air@v1.52.0/runner/proxy.go:157 +0x2b8

A theory is that proxy.Stop() is called before the <- ctx.Done() channel yields, allowing making a call on an empty value of the map.

plz provide OS version, and run air -v

[ndajr]

Hi @xiantang, here it is: #585

[davidovich]

On MacOS

GOARCH=arm64
GOOS=darwin

Built from a go install.

  __    _   ___  
 / /\  | | | |_) 
/_/--\ |_| |_| \_ v1.52.0, built with Go go1.22.0

If it matters, I run from make as a driver.

[davidovich]

Another thing comes to mind.

Merely starting air and closing it with SIGINT doesn't trigger the panic, I think we actually need to serve some pages to the browser to observe the failure (to have multiple subscribers ?).

But now, I can't seem to reproduce the panic...

I did observe though that if you SIGINT the air process before saving any content, the managed executable stays running.

[xiantang]

should be fixed in #585. will release in next version of air