The input validation for caching currently relies on having a stack of `scala.math.Equiv`, which is questionable since it can fallback to universal equality.
This is likely related to the intermittent caching behavior we are seeing in https://github.com/sbt/sbt/issues/3226
`F0`, `F1` and `Maybe` have become useless since Java 8 introduced
`Supplier`, `Function` and `Optional` in the default Java 8 standard
library.
Therefore, they are not necessary anymore. This change is required to
change some Zinc's and sbt APIs. They are not widely used, so the
changes will be small.
While running scripted, you see
```
ERROR StatusLogger Unable to create custom ContextSelector. Falling back to default.
java.lang.ClassCastException: Cannot cast org.apache.logging.log4j.core.async.AsyncLoggerContextSelector to org.apache.logging.log4j.core.selector.ContextSelector
at java.lang.Class.cast(Class.java:3369)
at org.apache.logging.log4j.util.LoaderUtil.newCheckedInstanceOf(LoaderUtil.java:201)
at org.apache.logging.log4j.util.LoaderUtil.newCheckedInstanceOfProperty(LoaderUtil.java:226)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.createContextSelector(Log4jContextFactory.java:97)
at org.apache.logging.log4j.core.impl.Log4jContextFactory.<init>(Log4jContextFactory.java:58)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at java.lang.Class.newInstance(Class.java:442)
at org.apache.logging.log4j.LogManager.<clinit>(LogManager.java:94)
at org.apache.logging.log4j.spi.ThreadContextMapFactory.createThreadContextMap(ThreadContextMapFactory.java:73)
at org.apache.logging.log4j.ThreadContext.init(ThreadContext.java:223)
at org.apache.logging.log4j.ThreadContext.<clinit>(ThreadContext.java:202)
at org.apache.logging.log4j.core.impl.ContextDataInjectorFactory.createDefaultInjector(ContextDataInjectorFactory.java:83)
at org.apache.logging.log4j.core.impl.ContextDataInjectorFactory.createInjector(ContextDataInjectorFactory.java:67)
at org.apache.logging.log4j.core.lookup.ContextMapLookup.<init>(ContextMapLookup.java:34)
at org.apache.logging.log4j.core.lookup.Interpolator.<init>(Interpolator.java:117)
at org.apache.logging.log4j.core.config.AbstractConfiguration.<init>(AbstractConfiguration.java:125)
at org.apache.logging.log4j.core.config.DefaultConfiguration.<init>(DefaultConfiguration.java:46)
at org.apache.logging.log4j.core.layout.PatternLayout$Builder.build(PatternLayout.java:650)
at org.apache.logging.log4j.core.layout.PatternLayout.createDefaultLayout(PatternLayout.java:487)
at sbt.internal.util.ConsoleAppender.<init>(ConsoleAppender.scala:245)
```
This aims to workaround the casting error during PatternLayout.createDefaultLayout()
that was originally used for ConsoleAppender.
The stacktrace shows it's having issue initializing default DefaultConfiguration.
Since we currently do not use Layout inside ConsoleAppender, the actual pattern is not relevant.
Eugene Yokota
Martin Duhem
jvican
Dale Wijnand
Guillaume Martres