Travis doesn't always fail when build fails

[helje5]

E.g.: https://travis-ci.org/NozeIO/Noze.io/jobs/215874965

Cloning /home/travis/build/NozeIO/Noze.io
error: The dependency graph could not be satisfied. The package (/home/travis/build/NozeIO/Noze.io) with version tag in range (0.5.0..<0.5.9223372036854775807) is not found. Found tags ([0.3.1337])
make[1]: Leaving directory `/home/travis/build/NozeIO/Noze.io/Samples'
The command "make samples" exited with 0.

No idea what is going on here. It says make samples exited with 0 even though we got the error. Is that our fault or is SPM not setting a proper exit code?