Feature request and horrible hack: break on next returned error

[Tom Payne]

Hi,

tl;dr would it be possible to break as soon as any function returns a non-nil error?

Apologies if this has already been requested. I did several searches but was unable to find an equivalent request.

More detail:

Go treats errors as first-class values. When a function returns an error, that error tends to bubble up the stack. The original source of the error is often lost and hard to track down. This is improving with Go 1.13's wrapped errors, but still requires the programmer to explicitly wrap those errors.

It would be really nice if there was a "continue until any function returns a non-nil error" command. This would require instrumenting any return statement that returns an error value, stopping execution at that point, and consequently reveal the underlying source of a bubbled-up error. Repeating the command would follow the bubbled error up the stack.

Many thanks for Delve - it's been invaluable for me.

Tom

[Tom Payne]

For what it's worth, implementing this would require effectively replacing every

    return err

with

    return breakOnError(err)

where breakOnError is:

func breakOnError(err error) error {

if err != nil {

runtime.Breakpoint()

}

return err

[Alessandro Arzilli]

You can do this, sort of, with some starlark scripting plus the API call
FindReturnLocations. I don't think it's feasible to do this for all
functions in the program, I think it would slow down execution too much and
generate too many false positives.

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[Tom Payne]

Thank you very much for the response - I'll investigate further.