Fixes https://github.com/sbt/sbt/issues/7327
**Problem**
In builds with mixed Scala patch versions (like scalameta),
it's possible for a core subproject to be set to the lastest 2.12.x,
but the compiler plugin component is cross published to 2.12.0 etc.
`++ 2.12.0` in this case does not work since sbt 1.7.x onwards requires
the queried Scala version to be listed in `crossScalaVersions`.
**Solution**
This implements sbt 1.6.x-like fallback mechanism,
but instead of using the queried version (e.g. 2.12.0) it will set
the Scala version to one of listed versions that is binary compatible.
Artifactory rejects the legacy artifacts of sbt plugin.
It is now possible to publish to Artifactory
by turning `sbtPluginPublishLegacyMavenStyle` off.
For an sbt plugin, we publish two POM files, the legacy one, and the
new Maven compatible one. The name of the new POM file contains the sbt
cross-version _2.12_1.0. The format of the new POM file is also slightly
different, because we append the sbt cross-version to all artifactIds of
sbt plugins. Hence Maven can resolve the new sbt plugin POM and its
dependencies.
When resolving an sbt plugin, we first try to resolve the new Maven POM
and if it fails we fallback on the legacy one. When parsing the new POM
format, we remove the sbt cross-version from all artifact IDs so that
there is no mismatch between old and new format of dependencies.
As of sbt 1.9, we publish deprecated and valid poms. In this test
we check that sbt resolve the valid pom of an sbt plugin and fallback
to the deprecated pom if the valid pom cannot be found.
Problem
-------
Since sbt-doge merger `++ <sv> <command1>` has used binary compatibility
as a test to select subproject, but it causes surprising situations like
sbt/sbt#6915, and it blurs the responsibility of YAML file and build
file as the version specified in the version can override the Scala
version test on local laptop.
Solution
--------
This removes the compatibiliy check (backward-only or otherwise),
and require that `<sv>` match one of `crossScalaVersions` using the new
Semantic Version selector pattern.
At some point the watchOnTermination callback stopped working. I'm not
exactly sure how or why that happened but it is fairly straightforward
to restore. The one tricky thing was that the callback has the signature
(Watch.Action, _, _, _) => State, which requires propagating the action
to the failWatch command. The easiest way to do this was to add a
mutable field to the ContinuousState. This is rather ugly and reflects
some poor design choices but a more comprehensive refactor is out of
the scope of this fix.
This commit adds a scripted test that ensures that the callback is
invoked both in the successful and unsuccessful watch cases. In each
case the callback deletes a file and we ensure that the file is indeed
absent after the watch exits.