_simplify_include_frames throws bounds error

[fredcallaway]

Original issue: JuliaLang/PackageCompiler.jl#517

When using a sysimage, _simplify_include_frames throws a bounds error at line 804 because i is 0.

julia/base/errorshow.jl

Line 804 in d732903

kept_frames[i:first_ignored] .= false

The immediate fix is to move the decrement to the top of the loop and start at i = length(trace) + 1. I can make a pull request for this.

This still gives really verbose stack traces when using a sysimage. I'd like to take a shot at improving that as well, but perhaps this should be done in a separate issue/pull request since it might require further discussion.

Thanks to @KristofferC for identifying the problem.

[c42f]

Yes this is a bug, thanks for the report.

I can make a pull request for this.

Perfect, please do. Two separate PRs seems fine.

Looking back at this code, I'm not sure why I wrote it as a while loop! It looks like it could be a for loop and you can just use kept_frames[1:first_ignored] .= false after the loop as it doesn't terminate early?

[fredcallaway]

Sorry, quick question: Is there a standard way to develop/test Base code (ideally using Revise.jl)? Normally I would do e.g. ] dev Base but that doesn't work. Didn't see anything about this in dev docs, but might have missed it.

[c42f]

TBH I haven't done this for a while. But you should be able to build Julia from source and use Revise.track(Base) to update Base while you edit the source (see https://timholy.github.io/Revise.jl/stable/#What-Revise-can-track-1)