GWT builds after updating the source maps jars have been showing some warnings while executing request factory tasks, this due to the fact that RequestFactoryExtractor is trying to recursively process classes from the build path and the recent sourcemaps classes in the new dependencies have some references to some google-auto annotations like @AutoValue (specifically the OriginalMapping class) but those are not present in the RequestFactoryExtractor task build path so they could not be loaded using the class-loader resulting in the warning we see in the build logs.

We can fix those warnings by either removing those references from the sourcemaps jars or by adding the missing classes to the build path, for example adding error_prone jars to the build path since it include those classes.