modules : tcl modules handle 'conflict' directive. This should comple…

…tely cover the functionality in spack#498

lib/spack/spack/modules.py

@@ -497,3 +497,19 @@ def header(self):
                 header += 'puts stderr "%s"\n' % line
             header += '}\n\n'
         return header
+
+    def module_specific_content(self, configuration):
+        naming_tokens = self.tokens
+        # Conflict
+        conflict_format = configuration.get('conflict', '')
+        if conflict_format:
+            for naming_dir, conflict_dir in zip(self.naming_scheme.split('/'), conflict_format.split('/')):
+                if naming_dir != conflict_dir:
+                    message = 'Conflict scheme does not match naming scheme [{spec}]\n\n'
+                    message += 'naming scheme   : "{nformat}"\n'
+                    message += 'conflict scheme : "{cformat}"\n'
+                    raise tty.error(
+                        message.format(spec=self.spec, nformat=self.naming_scheme, cformat=conflict_format)
+                    )
+            conflict_format = 'conflict ' + conflict_format
+            yield conflict_format.format(**naming_tokens)