Cache generated-gradle-jars into a tool-cache as well

[vlsi]

Have you tried caching generated-gradle-jars into tool-cache as well?

In other words:

1. Download Gradle
2. Execute it so it generates .gradle/caches/6.6/generate-gradle-jars/...
3. Ensure generated-gradle-jars is cached into tool-cache (e.g. copy it to gradle location)
4. As the tool is unpacked from the cache, copy generated-gradle-jars accordingly

See gradle/gradle#13982

Update: tool-cache does not cache files across job executions in GitHub runners (see actions/toolkit#58 (comment)), so currently tool-cache is not useful for caching gradle-generated-jars

[eskatos]

There's another aspect to this. Gradle can generate three different JARs in that directory, the gradle-api jar, the gradle-kotlin-dsl-extensions jar and the gradle-test-kit jar. Those are generated on-demand so which jars get generated depends on what the run build does.

[vlsi]

Thanks for the clarification.

As tool-cache is not reused across GitHub runners, it makes little sense to cache it into the tool-cache, so I close the issue as there's nothing to do :-(

It looks like the way to go is to solve gradle/gradle#13982 somehow (e.g. use classpath-only jar instead of a full-blown jar)