Occasional seg faults on 0.7/1.0

[nicoleepp]

Seg fault when using ExtensionPkg before using Unitful in another module:

This came up here lanl-ansi/PowerModelsAnnex.jl#29 and was resolved for that package specifically (turning precompilation off for the package that extends Unitful solves the error).

But I noticed that if that package did a using UnitfulUS before using Unitful it would also cause seg faults when loading using PowerModelsAnnex. Not sure the cause exactly but I suspect it might be related to Unitful itself/precompilation in general as this appears not to be specific to that extension of Unitful.

[cstjean]

I've had a ridiculous amount of segfaults since I started using Unitful. I don't think there's anything that can be done about it, besides filing reports with minimal code examples to julialang, unfortunately. Eg. JuliaLang/julia#29936 came from Unitful, and sounds very similar.

[nicoleepp]

Even with precompilation disabled, using Unitful on 0.7/1.0 will occasionally result in seg faults. @cstjean might be right in it being a julialang bug and not Unitful's fault; just seems to come up when using this package.

[ajkeller34]

I'd like to offer help, but usually segfaults are a Julia problem, unless it turns out I'm doing something unsafe in Unitful. I can audit my use of unsafe macros like @inbounds, etc. but to be honest I haven't had any segfaults. I also don't use separate unit packages that often, so maybe that points to the source of the problem?

[ajkeller34]

I'd be curious to know if the segfault situation has improved after merging #243. I don't have evidence to claim the issues are related although there were some unsafe uses of generated functions prior to that PR.

[cstjean]

FWIW I haven't had segfaults in a long time...

[omus]

We've still been seeing segfaults on our private CI. I'll set it up to make use of the master branch for now and report back.

[omus]

Yesterday we saw a segfault on the CI using the Unitful master branch. We were also using the PowerSystemsUnits.jl which was using v0.1.0 which may have been the cause of the segfault. We'll try to confirm this by using the v0.2.0 release.

[omus]

We haven't seen any segfaults with the updated version of PowerSystemsUnits.jl. I think it's safe to close this issue. We can re-open if they appear again.