crew install command outputs bad error message when formula has a non-existing dependency
If formula has a dependency that refers to the non-existing formula then crew install command outputs the following message:
zuav@ithilien$ ./crew -b install target/python:2.7.11
calculating dependencies for target/python:
error: undefined method `dependencies' for nil:NilClass
Correct message must be like this:
error: target/python depends on unknown formula 'foo'