panic because nil client in DynamicSamplingContextFromTransaction

[eliecharra]

Summary

In a context where we do not have initialized sentry, when finishing a transaction that have Sampled = sentry.SampledFalse will trigger a panic. I have a piece of code that conditionally force the sampling of a given transaction, this is working well but if I run my unit tests on the function that panics.

In general, I think the SDK should not panic if sentry is not configured.

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x635330]

goroutine 1 [running]:
github.com/getsentry/sentry-go.DynamicSamplingContextFromTransaction(0xc00015c000)
	/tmp/gopath1614006584/pkg/mod/github.com/getsentry/sentry-go@v0.16.0/dynamic_sampling_context.go:46 +0xb0
github.com/getsentry/sentry-go.(*Span).toEvent(0xc00015c000)
	/tmp/gopath1614006584/pkg/mod/github.com/getsentry/sentry-go@v0.16.0/tracing.go:405 +0x2e5
github.com/getsentry/sentry-go.(*Span).Finish(0xc00015c000)
	/tmp/gopath1614006584/pkg/mod/github.com/getsentry/sentry-go@v0.16.0/tracing.go:173 +0xb5

Steps To Reproduce

https://go.dev/play/p/vzesJ4l9TJa

Expected Behavior

No panic on Finish()

SDK

• sentry-go version: v0.16.0
• Go version: 1.19
• Using Go Modules? yes

Sentry

• Using hosted Sentry in sentry.io? yes

Happy to shoot a PR if you quickly explain how would you like to handle that 🙏🏻

[tonyo]

Thanks for the report @eliecharra, can confirm that it's crashing, which is totally undesirable.

We'll look into this (most likely won't happen in December, though), but in the meantime, could you perhaps initialize the Sentry SDK with empty DSN in your tests as a workaround?
E.g. something like

sentry.Init(sentry.ClientOptions{})

[eliecharra]

We'll look into this (most likely won't happen in December, though)

Sure sure no worries this is not a blocker at all 👍🏻 Also the workaround is perfectly acceptable so far 🙏🏻

Thanks for your work.

[cleptric]

@eliecharra Fixed in https://github.com/getsentry/sentry-go/releases/tag/v0.17.0