setup.py: Fail if old psamm-import is installed

Author: jonls

setup.py

@@ -16,12 +16,38 @@
 #
 # Copyright 2014-2017  Jon Lund Steffensen <[email protected]>
 
+from __future__ import print_function
+
+import sys
 from setuptools import setup, find_packages
+import pkg_resources
 
 # Read long description
 with open('README.rst') as f:
     long_description = f.read()
 
+# Test whether psamm-import is currently installed. Since the psamm-import
+# functionality was moved to this package (except Excel importers), only newer
+# versions of psamm-import are compatible with recent versions of PSAMM.
+try:
+    pkg_resources.get_distribution('psamm-import <= 0.15.2')
+except (pkg_resources.DistributionNotFound,
+        pkg_resources.VersionConflict):
+    pass
+else:
+    msg = (
+        'Please upgrade or uninstall psamm-import before upgrading psamm:\n'
+        '$ pip install --upgrade psamm-import\n'
+        ' OR\n'
+        '$ pip uninstall psamm-import'
+        '\n\n'
+        ' The functionality of the psamm-import package has been moved into'
+        ' the psamm package, and the psamm-import package now only contains'
+        ' the model-specific Excel importers.')
+    print(msg, file=sys.stderr)
+    sys.exit(1)
+
+
 setup(
     name='psamm',
     version='0.30',