It looks like CI hasn't been running on this and we've introduced some
problems. It looks like we had an off-by-one error in the check for
MSRV for deciding to run ui tests.
It turns out `value_name` appends, so by setting an implicit and
explicit `value_name`, the user gets both and `num_vals=2`.
There is still a question on `value_name` and whether its documentation
or behavior needs updating. If that changes, then this can be
simplified by reverting back.
Fixes#2632
When using `#[clap(flatten)]` inside of a `Subcommand`, we would do a
`from` instead of an `update`.
The challenge is knowing when we are
going into a flattened subcommand vs changing the variant. To resolve
this, I added a `Subcommand:has_subcommand(name)` trait method that we
generate, so we can ask.
I debated putting this fix inside of the Builder API but I figure this
makes it so you "pay for what you use", with the derive API giving it to
you "for free".
A potential next step is to improve the default value name. I tend to
use value_name to hint at how to use an argument, which correlates with
types. We could add a
`ValueName::value_name(fallback: &str) -> &str` with impls for common
types, so we get more of a usage-based result.
Fixes#2608
Improved the `impl`s of `From` for `&'help Yaml` to use expects with useful messages instead of unwraps. Also made changes to avoid potentially fetching redundant data from YAML hashes and unwrapping the same data multiple times. Finally, there are tests to ensure the panics are correct.
One of the challenges with #2255 is for the user to discover whats going
wrong. This helps by at least telling people how they got into a bad
state and we can search for the code within the derive.
PR #1637 switched clap to report `64` on errors and then #1653 switch it
to `2`, but both missed a case. This also documents the reason why inline
since I had to go and dig through the history to re-discover the
motivation.
Before, when doing an `update` involving subcommands, we generated
parsing rules for the `from` case instead, requiring all arguments to be
present.
This switches us to descending into `update` code and adds tests to
verify it works.
This is a part of #2605
