Stricter command line parsing

[LilithHafner]

It would be nice if = was required instead of optional for flags with arguments. This would make the following behavior error:

x@x:~/test$ julia --trace-compile --banner=no
               _
   _       _ _(_)_     |  Documentation: https://docs.julialang.org
  (_)     | (_) (_)    |
   _ _   _| |_  __ _   |  Type "?" for help, "]?" for Pkg help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 1.11.1 (2024-10-16)
 _/ |\__'_|_|_|\__'_|  |  Official https://julialang.org/ release
|__/                   |

julia> 
x@x:~/test$ ls
'--banner=no'
x@x:~/test$ cat -- --banner=no
precompile(Tuple{typeof(Base.print), Base.TTY, String})

Motivated by #56285

[fredrikekre]

Could probably be folded into #29669

[mbauman]

I think this is slightly different, and the minimal thing — erroring if a --flag arg is itself a flag without an explicit = — could be categorized as a UX bugfix.

[mgkuhn]

Requiring an = prefix to filename arguments of options may break TAB completion of such filenames in some shells. That makes it desirable to not require any prefix for filenames on the command line, IMHO.

Try (e.g. in zsh):

% touch test-file
% julia --trace-compile test-f[TAB]
% julia --trace-compile=test-f[TAB]

(However, some shells, e.g. bash-5.0 on Ubuntu, have been configured to autocomplete after --blahfoo=...[TAB].)

[mbauman]

I'm not suggesting requiring = in all situations. It would just be in the unlikely case that you want output precompiles (or whatever) to a file named --project.

[vtjnash]

We could error if the long opt value starts with -, but that would probably also still be breaking

[mgkuhn]

Note that the POSIX standard says in Section 12.2 Utility Syntax Guidelines:

Guideline 6:
Each option and option-argument should be a separate argument, except as noted in Utility Argument Syntax, item (2).

The convention of optionally also allowing the --arg=param form of an option argument, in addition to the standard form --arg param comes from the GNU glibc function getopt_long() AFAIK, so that's what users are likely have come to expect from lots and lots of other existing command-line utilities using that popular command-line parser function.

[JeffBezanson]

Just unix things.

[PallHaraldsson]

Can we just do this, and treat this as a bug, to not drop people's code:

julia --trace-compile my_invaluable_julia_code.jl

[PallHaraldsson]

Bump, can we make this error, even for 1.12 (to not silently delete files by accident)? We have a clarifying note in 1.11.x seemingly, and as far back as v1.10.8, on 2025-01-22

[adienes]

PRs welcome