Allow !include to skip missing files

[indigoviolet]

In shared repos, it would be nice to have a way for users to have their own unshared commands. One way to achieve this is to do

!include private.justfile, and then gitignore the private.justfile. Currently this requires private.justfile to exist.

Could we allow that to be missing? Or, do you have any other suggestions for this use case?

[neunenak]

Maybe a separate directive !include-optional that has the same behavior as !include but does not fail if the file doesn't exist?

I feel like at this point it's probably a good idea to think about what the syntax for specifying arbitrary modifiers to !include might look like, though. The current syntax is that any text at all after !include (minus whitespace-trimming) will be interpreted as a file path. We could add syntax for additional options after that filepath, which wouldn't break anyone's current workflow (maybe !include ./path/to/file.justfile --optional or !include ./path/to/file.justfile optional)?

Also see #929 for discussion about modules, which are supposed to be the more complex and configurable feature which !includes are a quick-and-dirty implementation of. Maybe !include directives can grow to do everything that would be desirable about a modules system.

[pprkut]

Imports may be made optional by putting a ? after the import keyword

I think this is already implemented now @casey

[casey]

@pprku Thank you! This is now implemented, you can do import? 'some.justfile' and it will not throw an error if some.justfile isn't present.