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Does `hostLookupOrder` function in `net/conf.go` need to check nil pointer? #39239

psy-core opened this issue May 25, 2020 · 2 comments


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@psy-core psy-core commented May 25, 2020

I just read the source code about hostLookupOrder function in net library:

if c.netGo || r.preferGo() {

I noticed that r.preferGo() not check if r is nil.

but the function canUseCgo in this conf.go just call it with this:

return c.hostLookupOrder(nil, "") == hostLookupCgo

which Resolver param is nil. Am i missing something?

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@davecheney davecheney commented May 25, 2020

In Go it is ok to call a method on a nil value. net.Resolver deals with this internally

func (r *Resolver) preferGo() bool { return r != nil && r.PreferGo }

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@psy-core psy-core commented May 25, 2020

That's incredible. I never thought It could be used like this. Thank you very much.

@psy-core psy-core closed this May 25, 2020
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