ENSIME doesn't give warnings or show errors on compiling Scala projects

Question

I have a basic Scala project setup that works well when it works. I'm using Emacs with ENSIME and so far have managed to get a hello world program to work. The problem: ENSIME will never tell me if the build failed to complete. Doing C-c C-b b always results in a window that says

latest compilation results: 0 errors, 0 warnings

even when it fails to compile at all. This is true when:

• There are syntax errors
• Target build directory doesn't exist and therefore .class files aren't generated
• There are dependency problems of whatever kind, or erroneously named files/anythings

How can I get ENSIME to tell me when something goes wrong? Did I install it incorrectly? Everything else works, and when the project is correct it builds fine.

Additionally, if that's not what it was meant to show, then what does it interpret as an error?

Answer 1

This was a bug, the ensime builder was discarding all errors and warnings from the Scala compiler. This is fixed in the latest git tree:

https://github.com/ensime/ensime-src.git