Improve type stability for tryparse VersionNumber

[rikhuijzer]

I noticed that LaTeXStrings is causing 297 method invalidations:

inserting firstindex(s::LaTeXString) in LaTeXStrings at /home/rik/git/LaTeXStrings.jl/src/LaTeXStrings.jl:108 invalidated:
   backedges: 1: superseding firstindex(s::AbstractString) in Base at /nix/store/31534zna4n6p2s0jwadn8jl6lkvxqjch-julia_16/share/julia/base/strings/basic.jl:180 with MethodInstance for firstindex(::AbstractString) (297 children)

Specifically, the invalidation tree starts with

 firstindex(::AbstractString)
   match(::Regex, ::AbstractString)
     tryparse(::Type{VersionNumber}, ::AbstractString)

If I understand invalidations correctly, this invalidation will happen for any package which defines a new firstindex(::T) where T isa AbstractString. Although they can fix it by also defining match(r::Regex, T); it is probably a good idea to avoid these invalidations altogether.

[rikhuijzer]

I think that the error on linx32 is unrelated, because the same occurs at #40523.

[simeonschaub]

Did you confirm with SnoopCompile that this fixes the invalidations? Otherwise LGTM

[rikhuijzer]

Did you confirm with SnoopCompile that this fixes the invalidations?

No, sorry. I did not do that. That would require building Julia from source and then running SnoopCompile on the package again, am I right?

[jebej]

Wouldn't all the other methods that call firstindex still get invalidated here? IIUC this change would only protect tryparse.

[jebej]

I think I misunderstood: the methods invalidated are methods that call tryparse.

[simeonschaub]

No, sorry. I did not do that. That would require building Julia from source and then running SnoopCompile on the package again, am I right?

You could actually also click on Details of the tester for your specific OS and then look up the download_url under the Build Properties tab, which will contain the built binaries. Just as a tip. But otherwise, yes, that's how you would do it.

[jebej]

On the CI build:

inserting firstindex(s::LaTeXString) in LaTeXStrings at C:\Users\Jeremy\.julia\packages\LaTeXStrings\anRaX\src\LaTeXStrings.jl:108 invalidated:
   backedges: 1: superseding firstindex(s::AbstractString) in Base at strings/basic.jl:180 with MethodInstance for firstindex(::AbstractString) (1 children)

[rikhuijzer]

You could actually also click on Details of the tester for your specific OS and then look up the download_url under the Build Properties tab, which will contain the built binaries. Just as a tip. But otherwise, yes, that's how you would do it.

Thank you for the advise. I will do that before I submit any new PRs on invalidations. 👍

On the CI build:

inserting firstindex(s::LaTeXString) in LaTeXStrings at C:\Users\Jeremy\.julia\packages\LaTeXStrings\anRaX\src\LaTeXStrings.jl:108 invalidated:
   backedges: 1: superseding firstindex(s::AbstractString) in Base at strings/basic.jl:180 with MethodInstance for firstindex(::AbstractString) (1 children)

Thank you for checking!