A helpful error message if we encounter a GRBException while running the cpp solver. (#91)

Author: vineetbansal

setup.py

@@ -76,7 +76,7 @@ def build_extension(self, ext):
 
 setup(
     name='hatchet',
-    version='0.4.3',
+    version='0.4.4',
     packages=['hatchet', 'hatchet.utils', 'hatchet.utils.solve', 'hatchet.bin', 'hatchet.data'],
     package_dir={'': 'src'},
     package_data={'hatchet': ['hatchet.ini'], 'hatchet.data': ['*']},

src/hatchet/__init__.py

@@ -1,4 +1,4 @@
-__version__ = '0.4.3'
+__version__ = '0.4.4'
 
 import os.path
 from importlib.resources import path

src/hatchet/bin/HATCHet.py

@@ -683,7 +683,11 @@ def execute(args, basecmd, n, outprefix):
         else:
             raise RuntimeError(error('Failed to parse the output of the following command because the final objective was not found: \n\t\t{}\n'.format(cmd)))
     else:
-        raise RuntimeError(error("The following command failed: \n\t\t{}\nwith {}\n".format(cmd, buffer)))
+        if any('GRBException' in line for line in buffer):
+            msg = '\nYou likely have a licensing issue with Gurobi. Please run `hatchet check-solver` to ensure that the solver is working correctly.'
+        else:
+            msg = '\nUnexpected error during solve. Please run `hatchet check-solver` to ensure that the solver is working correctly.'
+        raise RuntimeError(error("The following command failed: \n\t\t{}\nwith {}\n{}".format(cmd, buffer, msg)))
 
     return obj