By removing all arguments, we've switched from an "unrecognized
argument" error to a "unrecognized subcommand" error. While the wording
has room for improvement, its at least progress on #2862.
Inspired by argcomplete, this provides Rust-implemented completions
- Only bash for now
- No subcommand support
- No flag value support
- No special settings support
- No handling of positions within positionals
- No prioritizing of required or removing of conflicts (including
self-conflicts)
Before, if two arguments were required *and* overrode each other, then
`cmd --opt=1 --other=2` succeded but `cmd --other=2` failed despite
ignoring `--opt=1`. Requiring `--opt=1` to be present but unavailable
doesn't help anyone and makes the behavior less predictable.
Now both commands will have the same behavior.
We had two different implementations of conflicts
- Validating conflicts
- Allowing conflicts to override `required`
- Missing members of a group conflicting with each other
- Missing symmetric conflicts (A conflicts with B so B conflicts with
A)
This consolidates their implementations which should fix overriding of
`required`.
`Command::_build_all` started as an internal function for
`clap_complete` as a stopgap until #2911. Overtime, we've been finding
more cases where this function needs to be called, so now we're going to
fully embrace it until #2911 so people aren't scrared off by the hidden
implementation from using it.
This was inspired by #3602
Comptibility: Though this adds a deprecation which we general reserve
for minor or major versions, this is enough of a corner case that I'm
fine doing this in a patch release.
In considering the design for this, we want:
- Ability to modify the argment list while maintaining the `Cursor` for
replacements
- Allow picking up subcommand parsing in the middle of short flags
- Ability to peek at the next item to determine if we want to treat it
as a flag or as a value
- Ability to detect started short and long arguments for completions
Longer term, we also want to consider:
- Allowing users to customize the lexer to support different syntaxes
Since we'll need `skip`, it made me wonder how to name `skip` and
`previous` to fit together, so I decided to play with `seek`. Its
probably over kill but wondering if its better.
Before, we had a generic `next` that provided the next item and peeked
at all remaining items. This was to work around the borrow checker for
modifying the position while accessing args.
We've now split `Input` into `RawArgs` and `ArgsCursor` so we don't have
overlapping borrows. This made it so we can split `next` into `next`,
`peek`, and `remaining`.
