rustbuild accepts `-h` but not `--help`

[arielb1]

$ python ../src/bootstrap/bootstrap.py -h
Usage: rust.py [options]

Options:
    -v, --verbose       use verbose output
        --config FILE   TOML configuration file for build
        --host HOST     host targets to build
        --build BUILD   build target of the stage0 compiler
        --target TARGET targets to build
    -s, --step STEP     build step to execute
        --stage N       stage to build
        --src DIR       path to repo root
    -j, --jobs JOBS     number of jobs to run in parallel
        --clean         clean output directory
    -h, --help          print this help message
$ python ../src/bootstrap/bootstrap.py --help
usage: bootstrap.py [-h] [--config CONFIG] [--clean] [-v]

Build rust

optional arguments:
  -h, --help       show this help message and exit
  --config CONFIG
  --clean
  -v, --verbose

[arielb1]

cc @alexcrichton

[alexcrichton]

Should be an easy fix! Would be quite willing to mentor anyone interested

[GlenDC]

I was investigating in fixing this issue, but it seems like --help works, while -h doesn't work. And it doesn't work because it is filtered out of sys.argv before we pass it onto the argument parsing?

You can see this in bootstrap.h#L349: args = [a for a in sys.argv if a != '-h']. Why is the -h flag filtered out? Also @arielb1 I never see the help/usage description of the first command you posted.

We're talking about the rust-lang/rust/src/bootstrap/bootstrap.py script, no?

[alexcrichton]

Ah I think that'd do it, yeah. We probably just need to filter out both -h and --help from sys.argv in python. The idea is that those flags should be forwarded to the Rust build system rather than the python script (the help printed for --help) as the python script doesn't have the full suite of options, just a subset.