Currently every component references nightly composite update site during the build to get dependencies. That leads to possibility to introduce cycle dependencies between components that is not detected by build.
Here is example of PR introduced a cycle between JST and VPE. Build works because JST have access to VPE BrowserSim through nightly composite update site.
The solution would be to reference specific nightly update sites for modules that are dependencies for current one.
In this case JST should have reference only to base composite nightly update site. That would solve cycle dependency detection problem and speed up the build because it would not require to download and analyse all metadata from jbosstools nightly composite update site.