Compiled binaries pass --help to IO.args (#934)

[YidaWeng]

Summary

• A compiled C or JS binary treated --help as a runtime flag and never ran main, so a Bend CLI could not implement its own help without -- --help (Let compiled binaries pass --help through to IO.args #934).
• Runtime help is now --bend-help. --help (and any other non-runtime flag) reaches IO.args() on both lanes.
• Guide and tests/io/args.bend note the reserved options.

Test plan

• demo --help prints --help (C and JS); demo --bend-help prints runtime usage and exits 0
• demo / demo hello still print (none) / hello
• tests/io/args.bend — interp + C print 0
• bun gates/repo.ts — PASS 46 / 46
• Cluster gates/test.ts (no minis here)

Made with Cursor

[nicolas-abril]

I feel like we should have a better solution to not clash with the application's flags, --gpu is also somwhat likely (of course not nearly as much as --bend-help)

[nicolas-abril]

Thank you, the rename is right and we reproduced #934 on both lanes: on main a compiled binary eats --help, on this branch it reaches IO.args and --bend-help prints the usage.

One correction before it can merge. The new sentence in guide/GUIDE.md and the header of tests/io/args.bend say the runtime keeps --threads, --gpu, --gpu-build and --bend-help. That is only true of the C binary: the JS runtime's cli() skips --threads and --gpu alone, so bun x.js --gpu-build hands --gpu-build to the program (args.bend prints 1 under bun, before and after this PR). Please either word the list as what every lane keeps, or keep the old wording ("less the runtime's own options") and name only --bend-help as the new one. With that, we merge.

Note: this reply was written by an AI after it reported the issue to me and I made the decision. If anything here is wrong, reply and I will review it myself.

[YidaWeng]

Fixed in 0414ed9: the guide goes back to "less the runtime's own options (a -- ends them)" and names --bend-help as the new one; tests/io/args.bend now spells out each lane — the C binary keeps --threads, --gpu, --gpu-build and --bend-help, the JS lane only --threads, --gpu and --bend-help.

Checked on both lanes with a build of tests/io/args.bend:

C   --help        -> 1      JS  --help        -> 1
C   --threads 4   -> 0      JS  --threads 4   -> 0
C   --gpu on      -> 0      JS  --gpu on      -> 0
C   --gpu-build   -> 1      JS  --gpu-build   -> 1   (unchanged, pre-existing)
C   --bend-help   -> usage  JS  --bend-help   -> usage

bun gates/repo.ts: PASS 46 / 46.