On Fri, 2023-11-17 at 11:45 -0500, Andrii Nakryiko wrote:
[...]
> I think this implementation has an undesired surprising behavior.
> Imagine you have a log like this:
>
> A
> C
> D
> B
>
>
> And you specify
>
> __msg("A")
> __nomsg("B")
> __msg("C")
> __msg("D")
> __msg("B")
>
> Log matches the spec, right? But your implementation will eagerly reject it.
>
> I think you can implement more coherent behavior if you only strstr()
> __msg() specs, skipping __nomsg() first. But on each __msg one, if
> successful, you go back and validate that there are no matches for all
> __nomsg() specs that you skipped, taking into account matched
> positions for current __msg() and last __msg() (or the start of the
> log, of course).
>
> Not sure if I explained clearly, but the idea is to postpone __nomsg()
> until we anchor ourselves between two __msg()s. And beginning/end of
> verifier log are two other anchoring positions.
Yes, makes total sense, thank you for spotting it. I can fix this and
submit this patch as an unrelated change or just drop it, what would
you prefer?
