When a property wrapper is applied to a property, the property's
storage is given a name with a prefixed underscore. That is,
for a property named `x`, the actual storage is named `_x`.
That prefixed storage is what is visible through reflection, so
when building an ArgumentSet from a command type's Mirror, we
need to remove the leading underscore. This is done when creating
an InputKey for each property.
However, InputKeys are also created from CodingKeys during
decoding of a ParsableCommand. These CodingKeys _do not_ have
the leading underscore that is visible, so any underscores
that appear are actually from the declaration of the property
with an underscored name. Removing leading underscores from
CodingKey names results in a mismatch when trying to find
the decoded value.
This change simplifies the InputKey type to use an array
path instead of an indirect enum and removes the leading
underscore dropping when creating an InputKey from a CodingKey.
rdar://104928743
* Use existential CodingKey parameters consistently
Swift 5.7 supports implicit opening for existentials, so these
conversions from `CodingKey` parameters to pass to methods that
are generic over `CodingKey` work fine. Prior to Swift 5.7, however,
these don't compile, with the message that `CodingKey` doesn't conform
to itself.
* Bump the required Swift version for the count-lines test
The overload resolution for the `static func main()` in an `@main`
type still had issues in Swift 5.6, such that a package with a min.
platform below that which works for concurrency backdeployment doesn't
properly resolve the AsyncParsableCommand `main()` function. In
Swift 5.7, this is properly resolved, so just the availability on
the main type is sufficient.
This change just skips the test of `count-lines` prior to Swift 5.7,
so that we can maintain the open platform minimum for the package
as a whole.
Nate Cook
David Peterson