Improve the annotated join method and dispatch

[tecosaur]

With the initial implementation, join could work for AnnotatedStrings, however only when the eltype of the iterator or delim was itself a Annotated{String,Char}. This was better than nothing, but seems inconsistent in the face of mixed iterators.

Furthermore, the implementation of an annotated join was far from optimised, relying on zipping and then calling annotatedstring(xs...). By contrast, the non-annotated implementation relies on printing to IO and even has manually defined alternative methods for optional arguments to minimise code generation.

With the advent of AnnotatedIOBuffer and _isannotated, we can improve on both those aspects. The new AnnotatedIOBuffer type allows us to re-use the optimised join(::IO, ...) methods, and we can more reliably dispatch to them with _isannotated. Since this is a type-based decision, the Julia compiler is kind enough to work out which branch is taken at compile-time, making this zero-overhead in the unannotated case.

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Depends on #51806 and #51807

[tecosaur]

Now that the prerequisite PRs have been merged 🥳, we can now think about merging this one.

[oscardssmith]

looks good to me

[tecosaur]

Huh, I see CI actually wasn't happy. I pulled the latest changes in master and tested locally, and it works. Also tweaked an existing test to cover one of the new behaviours from this change.

CI should be happy now 🤞, and I presume this would be good to merge then?

[tecosaur]

I'm a bit confused by the fact that CI is showing errors that I don't see locally, namely:

Error in testset strings/annotated:
Test Failed at /cache/build/tester-amdci5-15/julialang/julia-master/julia-4dd043e483/share/julia/test/strings/annotated.jl:94
  Expression: join([str1, str1], ' ') == Base.AnnotatedString("test test", [(1:4, :label => 5), (6:9, :label => 5)])
   Evaluated: "test test" == "test test"
Error in testset strings/annotated:
Test Failed at /cache/build/tester-amdci5-15/julialang/julia-master/julia-4dd043e483/share/julia/test/strings/annotated.jl:98
  Expression: join([str1, str1], Base.AnnotatedString(" ", [(1:1, :label => 2)])) == Base.AnnotatedString("test test", [(1:4, :label => 5), (5:5, :label => 2), (6:9, :label => 5)])
   Evaluated: "test test" == "test test"

when if I do ./julia test/runtests.jl strings/annotated I see

Test          (Worker) | Time (s) | GC (s) | GC % | Alloc (MB) | RSS (MB)
strings/annotated  (1) |        started at 2024-02-05T12:48:01.929
strings/annotated  (1) |     2.73 |   0.04 |  1.3 |     367.04 |   665.82

Test Summary: | Pass  Total  Time
  Overall     |  476    476  4.1s

[vtjnash]

Error in testset strings/annotated:
Test Failed at /cache/build/tester-amdci5-15/julialang/julia-master/julia-4dd043e483/share/julia/test/strings/annotated.jl:94
  Expression: join([str1, str1], ' ') == Base.AnnotatedString("test test", [(1:4, :label => 5), (6:9, :label => 5)])
   Evaluated: "test test" == "test test"

This seems somewhat a lack of a complete show method being implemented. The show for annotated string should probably do something like wrapping the printing in a call to Base.AnnotatedString (e.g. use the default printing) or re-format it using the StyledStrings.jl styled"{:}" printing

[tecosaur]

This seems somewhat a lack of a complete show method being implemented. The show for annotated string should probably do something like wrapping the printing in a call to Base.AnnotatedString (e.g. use the default printing) or re-format it using the StyledStrings.jl styled"{:}" printing

When you're using the REPL, and styling attributes, I find that the current show works fairly well,

but yes, this is annoying when looking at it in CI. For CI alone, displaying the value like the constructor (Base.AnnotatedString("test test", [(1:4, :label => 5), (6:9, :label => 5)])) may be the most helpful.

[tecosaur]

Would having a different show form for AnnotatedStrings within tests be a bit silly?

[tecosaur]

For now I'll temporarily change the show method in this PR to get some more useful CI output.

[tecosaur]

This is stange. After adding the logging, it's not complaining about the difference anymore (I just see doctest failures resulting from the log-more-info change). Was it fixed by rebasing to a newer master?

[tecosaur]

Tests have successfully run on everything but the Mingw32 Windows builds. I think this is good to go now.