The goal of this commit is to address unknown licenses when producing
the dependencies info report. We have two different checks that we run
on licenses. The first check is whether or not we have stashed a copy of
the license text for a dependency in the repository. The second is to
map every dependency to a license type (e.g., BSD 3-clause). The problem
here is that the way we were handling licenses in the second check
differs from how we handle licenses in the first check. The first check
works by finding a license file with the name of the artifact followed
by the text -LICENSE.txt. Yet in some cases we allow mapping an artifact
name to another name used to check for the license (e.g., we map
lucene-.* to lucene, and opensaml-.* to shibboleth. The second check
understood the first way of looking for a license file but not the
second way. So in this commit we teach the second check about the
mappings from artifact names to license names. We do this by copying the
configuration from the dependencyLicenses task to the dependenciesInfo
task and then reusing the code from the first check in the second
check. There were some other challenges here though. For example,
dependenciesInfo was checking too many dependencies. For now, we should
only be checking direct dependencies and leaving transitive dependencies
from another org.elasticsearch artifact to that artifact (we want to do
this differently in a follow-up). We also want to disable
dependenciesInfo for projects that we do not publish, users only care
about licenses they might be exposed to if they use our assembled
products. With all of the changes in this commit we have eliminated all
unknown licenses. A follow-up will enforce that when we add a new
dependency it does not get mapped to unknown, these will be forbidden in
the future. Therefore, with this change and earlier changes are left
having no unknown licenses and two custom licenses; custom here means it
does not map to an SPDX license type. Those two licenses are xz and
ldapsdk. A future change will not allow additional custom licenses
unless they are explicitly whitelisted. This ensures that if a new
dependency is added it is mapped to an SPDX license or mapped to custom
because it does not have an SPDX license.
This commit adds a check that any class in X-Pack that is a feature
aware custom also implements the appropriate mix-in interface in
X-Pack. These interfaces provide a default implementation of
FeatureAware#getRequiredFeature that returns that x-pack is the required
feature. By implementing this interface, this gives a consistent way for
X-Pack feature aware customs to return the appopriate required feature
and this check enforces that all such feature aware customs return the
appropriate required feature.