[migration] don't add CWUniqueConstraint if already there (may occurs when running a migration in multiple times
"""This module compare the Schema on the file system to the one in the database"""
from cStringIO import StringIO
from cubicweb.web.schemaviewer import SchemaViewer
from logilab.common.ureports import TextWriter
import difflib
viewer = SchemaViewer()
layout_db = viewer.visit_schema(schema, display_relations=True)
layout_fs = viewer.visit_schema(fsschema, display_relations=True)
writer = TextWriter()
stream_db = StringIO()
stream_fs = StringIO()
writer.format(layout_db, stream=stream_db)
writer.format(layout_fs, stream=stream_fs)
stream_db.seek(0)
stream_fs.seek(0)
db = stream_db.getvalue().splitlines()
fs = stream_fs.getvalue().splitlines()
open('db_schema.txt', 'w').write(stream_db.getvalue())
open('fs_schema.txt', 'w').write(stream_fs.getvalue())
#for diff in difflib.ndiff(fs, db):
# print diff