With erroneous module names and/or erroneous import specifications, the build stops with an error from the Stratego compiler, followed by an exception (which should not be shown, I assume). After fixing such errors, the following build still fails with another exception:

org.metaborg.core.MetaborgException: Previous build failed and no change in the build input has been observed, not rebuilding. Fix the problem, or clean and rebuild the project to force a rebuild

As suggested by the exception message, a forced rebuild works.

Eclipse: org.eclipse.platform.ide 4.6.0.I20160606-1100
Spoofax: org.metaborg.spoofax.eclipse 2.0.0.20160705-092320-master
System: Mac OS X x86_64 10.11.5

Submitted by Guido Wachsmuth on 12 July 2016 at 01:10

When the Stratego compiler fails in such a way, I think it does not generate a complete dependency file, meaning that Pluto forgets about many dependencies and does not see that a change in Stratego files requires a rebuild.

This is fixed in the latest nightly.