clap 3.1 renamed `App` to `Command`. When we upgrade to clap v4, the
lifetime will be removed and we can just use `clap::Command` instead of
a type alias. This is prep for that.
- One parser change found by `cargo_config::includes` is that clap 2
would ignore any values after a `=` for flags.
`cargo config --show-origin` is a flag but the test passed `--show-origin=yes` which
happens to give the desired result for that test but is the same as
`--show-origin=no` or `--show-origin=alien-invasion`.
- The parser now panics when accessing an undefined attribute but clap
takes advantage of that for sharing code across commands that have
different subsets of arguments defined. I've extended clap so we can
"look before you leap" and put the checks at the argument calls to
start off with so its very clear what is tenuously shared. This
allows us to go in either direction in the future, either addressing
how we are sharing between commands or by moving this down into the
extension methods and pretending this clap feature doesn't exist
- On that topic, a test found clap-rs/clap#3263. For now, there is a
hack in clap. Depending on how we fix that in clap for clap 4.0, we
might need to re-address things in cargo.
- `value_of_os` now requires setting `allow_invalid_utf8`, otherwise it
asserts. To help catch this, I updated the argument definitions
associated with lookups reported by:
- `rg 'values?_os' src/`
- `rg 'values?_of_os' src/`
- clap now reports `2` for usage errors, so we had to bypass clap's
`exit` call to keep the same exit code.
BREAKING CHANGE: API now uses clap3