From: Christopher Allan Webber <cwebber@dustycloud.org>
Date: Mon, 4 Mar 2013 16:57:21 +0000 (-0600)
Subject: Give a more useful error if a table already exists and so we can't create it during... 
X-Git-Url: https://vcs.fsf.org/?a=commitdiff_plain;h=7e4a87dca5c8afa13b64f76c4b9ce440d38a91b5;p=mediagoblin.git

Give a more useful error if a table already exists and so we can't create it during migrations

This commit sponsored by Andrzej Prochyra.  Thanks!
---

diff --git a/mediagoblin/db/migration_tools.py b/mediagoblin/db/migration_tools.py
index e5380a3b..c0c7e998 100644
--- a/mediagoblin/db/migration_tools.py
+++ b/mediagoblin/db/migration_tools.py
@@ -17,6 +17,9 @@
 from mediagoblin.tools.common import simple_printer
 from sqlalchemy import Table
 
+class TableAlreadyExists(Exception):
+    pass
+
 
 class MigrationManager(object):
     """
@@ -128,7 +131,10 @@ class MigrationManager(object):
         # sanity check before we proceed, none of these should be created
         for model in self.models:
             # Maybe in the future just print out a "Yikes!" or something?
-            assert not model.__table__.exists(self.session.bind)
+            if model.__table__.exists(self.session.bind):
+                raise TableAlreadyExists(
+                    u"Intended to create table '%s' but it already exists" %
+                    model.__table__.name)
 
         self.migration_model.metadata.create_all(
             self.session.bind,