This commit makes it possible for the sbt server to render the same ui
to multiple clients. The network client ui should look nearly identical
to the console ui except for the log messages about the experimental
client.
The way that it works is that it associates a ui thread with each
terminal. Whenever a command starts or completes, callbacks are invoked
on the various channels to update their ui state. For example, if there
are two clients and one of them runs compile, then the prompt is changed
from AskUser to Running for the terminal that initiated the command
while the other client remains in the AskUser state. Whenever the client
changes uses ui states, the existing thread is terminated if it is
running and a new thread is begun.
The UITask formalizes this process. It is based on the AskUser class
from older versions of sbt. In fact, there is an AskUserTask which is
very similar. It uses jline to read input from the terminal (which could
be a network terminal). When it gets a line, it submits it to the
CommandExchange and exits. Once the next command is run (which may or
may not be the command it submitted), the ui state will be reset.
The debug, info, warn and error commands should work with the multi
client ui. When run, they set the log level globally, not just for the
client that set the level.
Fixes#4293
Ref #4231, #4065
This fixes the regression on sbt 1.2.0 that displays a lot of warnings about configurations.
The warning was added in #4231 in an attempt to fix#4065. This actually highlights somewhat loose usage of configurations among the builds in the wild, and the limitation on the current slash syntax implementation.
I think we can remove this warning for now, and try to fix#4065 by making slash syntax more robust. In particular, we need to memorize the mapping between the configuration name and Scala identifier across the entire build, and use that in the shell.