Add command line option for short banner

[LilithHafner]

  o  | Version 1.10.0-beta1 (2023-07-25)
 o o | Official https://julialang.org/ release

  o  | Version 1.11.0-DEV.229 (2023-07-29)
 o o | scoped-export/de8be2b039* (fork: 35 commits, 0 days)

(it has color, too)

[LilithHafner]

I've reviewed and approve @c42f's contribution to this PR.

[c42f]

I've looked through all this again including your parts @LilithHafner. I added another two tiny tests to cover the command line argument more thoroughly.

It looks good to me I say we merge it as soon as CI passes.

Personally I'll be turning this on by default for all my Julia aliases :)

[c42f]

The windows test failure here looks spurious - something to do with temporary files and the file system.

[tecosaur]

@LilithHafner did you by any chance see my efforts to support multiple banner sizes based on the terminal resolution?

[LilithHafner]

I did not, would you share a link?

[tecosaur]

I had a look when I sent that message, unfortunately it seems like the discussion has disappeared into the slack-hole. That said, I can do a brief recap and demo.

I don't think it's very nice how with a narrow or small terminal window, the Julia banner can (a) get ruined by line wrapping, or (b) take up almost all of the window. So, I designed a number of alternative scaling of the Julia banner that are picked between based on displaysize(io).

[LilithHafner]

I love the rendering of "Julia" in the 8x55 version!

[tecosaur]

The 8 or less rows options do assume the Julia mono font, but I like them. I'd be happy to PR these once StyledStrings is in, but I do think we'd then want to switch out --banner=short to --banner=<int>, say with 0 being the smallest size and going up from there.

[LilithHafner]

The deadline to cleanly swap that out (i.e. drop support for --banner=short) is 1.11

[tecosaur]

Mmm, I'd also like to get StyledStrings in with 1.11 (and Stefan/Kristopher/Jameson seemed to think that reasonable I spoke with them at JuliaCon).

[LilithHafner]

For @c42f and others who may want to opt into this by default, here's a little monstrosity to put in startup.jl that does that

# Use --short banner by default (https://github.com/JuliaLang/julia/pull/50726#issuecomment-1939089858)
if VERSION >= v"1.11.0-DEV.222" && isinteractive()
    c_options = cglobal(:jl_options, Base.JLOptions)
    opts = unsafe_load(c_options)
    if opts.banner == -1 && isa(stdin, Base.TTY)
        # opts.banner = 2
        fields = fieldnames(Base.JLOptions)
        args = (f == :banner ? 2 : getfield(opts, f) for f in fields)
        new_opts = Base.JLOptions(args...)
        unsafe_store!(c_options, new_opts)
    end
end

[tecosaur]

That almost makes me wonder if a JULIA_BANNER env var may be worth it.

[LilithHafner]

Or a ShortBanner package. Then it would just be using ShortBanner (and have a lower startup time). I may make that package a couple weeks after the 1.11 feature freeze once these internals are a bit more settled.

[vtjnash]

FWIW, I think a slightly more standard form of this would use:

        unsafe_store!(Ptr{typeof(banner)}(c_options) + fieldoffset(opts, :banner), 2)

[LilithHafner]

That fieldoffset method does not exist.

julia> only(methods(fieldoffset))
fieldoffset(x::DataType, idx::Integer)
     @ Base reflection.jl:917

[vtjnash]

Ugh, you are right, and it really should exist for this use case. Anyways, here is the verbose version of it then:

julia> code_typed() do; fieldoffset(Base.JLOptions, Base.fieldindex(Base.JLOptions, :banner)); end
1-element Vector{Any}:
 CodeInfo(
    @ REPL[7]:1 within `#21`
1 ─     return 0x0000000000000001
) => UInt64

[c42f]

Oh my. I love that use of code_typed() with the lambda 😍