Fix stack popping logic in Raku lexer

[donaldh]

This fixes an array index bounds error.

[alecthomas]

This fails the tests for some reason.

[CIAvash]

@donaldh is this fixing a particular bug? Because I think it would be better if the bug gets added as a test. It's possible the issue is somewhere else.

[donaldh]

It's been a while since this issue first arose but here is some quick info. When I run the latest hugo from brew on my site:

hugo v0.125.7+extended darwin/amd64 BuildDate=2024-05-08T14:46:24Z VendorInfo=brew

ERROR Could not render org: could not write output: runtime error: index out of range [-1]. Using unrendered content.

I will need to patch hugo to output file and line info to narrow down what triggers this.

[donaldh]

Now that I have added filenames to the hugo logging, I am getting multiple errors and it's different files each run. That suggests it's racy and there's some shared state between goroutines. When I set HUGO_NUMWORKERMULTIPLIER=1 to serialise the hugo build, I no longer see the error.

Apologies for the noise, it is an issue somewhere else, though I'm not sure if the bug is in chroma, go-org or hugo.

Looking back at the change I made, moving the pop operation was obviously the wrong thing to do. However an array bounds error will happen if the stack length == 1 when popRule() is called. Perhaps this should never happen, but maybe the condition should be if ok && len(stack) > 1 {

[CIAvash]

Yeah, probably.