test-migrations: Clean up a bit.

tools/test-migrations

@@ -2,9 +2,13 @@
 set -e
 echo 'Testing whether migrations are consistent with models'
 
-new_auto_named_migrations=$(./manage.py showmigrations | grep -v '0004_auto_20160423_0400\|0005_auto_20160727_2333\|0052_auto_fix_realmalias_realm_nullable\|0089_auto_20170710_1353\|0002_auto_20150110_0810\|0003_auto_20150817_1733\|0004_auto_20160205_1827\|0005_auto_20160224_0450' | grep "_auto_20" || true)
-# We check if there is any new migration with the 'auto' keyword in its name and
-# cause a error to rename to a more meaningful name
+# Check if any migration looks to have a meaningless 'auto' name,
+# other than the existing handful from 2016 and 2017.
+new_auto_named_migrations=$(./manage.py showmigrations \
+    | grep -E ' [0-9]{4}_auto_' \
+    | grep -Eve ' [0-9]{4}_auto_201[67]' \
+             -e ' 0052_auto_fix_realmalias_realm_nullable' \
+ || true)
 if [ "$new_auto_named_migrations" != "" ]; then
     echo "ERROR: New migrations with unclear automatically generated names."
     echo "Please rename these migrations to have readable names:"
@@ -22,6 +26,6 @@ if ! ./manage.py makemigrations --check --dry-run; then
     echo 'See https://zulip.readthedocs.io/en/latest/subsystems/schema-migrations.html for details.'
     echo
     exit 1
-else
-    echo "Success!  Migrations are consistent with models."
 fi
+
+echo "Success!  Migrations are consistent with models."