Rename early command in sbt 1.0

[eed3si9n]

problem

sbt uses -- in a way inconsistent with Unix convention. (e93c445):

> help --
--<command>

        Schedules an early command, which will be run before other commands on the command line.
        The order is preserved between all early commands, so `sbt --a --b` executes `a` and `b` in order.

expectation

I'm not sure what the purpose of the early command is. Can we remove this in sbt 1.0?

notes

• http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap12.html
• https://www.gnu.org/prep/standards/html_node/Command_002dLine-Interfaces.html

/cc @jsuereth, @dwijnand

Ref #1041

[dwijnand]

I agree we should move towards the Unix convention, as demonstrated by the fall out of #1041.

One way I know this is used is for log levels in sbt-extras: dwijnand/sbt-extras@90170b2

[eed3si9n]

The early commands gets executed pretty early, like before the session gets initialized, so combining with error, and making --error as if it's an option makes a lot of sense.
But given that the options used by shell script uses single hyphen like -no-colors, the use of double hyphens -- is too subtle. Maybe it's better to explicitly add support for log level options if that's the primary use case.

[DavidPerezIngeniero]

What is a typical use case of the early command?

[eed3si9n]

@DavidPerezIngeniero The only one we've identified is reducing the log level on startup as --warn. This will now be -warn with single hyphen in 0.13.13 onward.