Upstream UNSTABLE dependency build does not trigger downstream modules

[flanagaj]

We have identified an quirk in the IVY plugin module which causes upstream UNSTABLE modules to be rescheduled to build even though there has not been an SCM change to the UNSTABLE project. The issue here is that a downstream module of the UNSTABLE module which does have an SCM change does not get triggered to build as the UNSTABLE module continually remains in the UNSTABLE state and does not trigger a downstream dependency build.

Whilst I appreciate that an UNSTABLE (failed unit tests) module should be fixed, I don't agree that it should stop the triggering of downstream modules. I would suggest that either the code be modified so that UNSTABLE builds are not rescheduled unless a material change has occurred to the module OR the plugin is modified so the dev team can configure whether downstream dependencies are triggered.

If I had a dependency tree as shown below.

C-->B-->A

and A was unstable due to a failed unit test, but developers where commiting many changes to C and B, neither C and B would be triggered to build whilst A remained UNSTABLE. This leaves the dev team very blind as C and B would appear to be perfectly fine when viewed in the module view, but the reality is that they have not been built.