[migration] Adding migration to remove empty in/not-in filters

superset/migrations/versions/afb7730f6a9c_remove_empty_filters.py

@@ -0,0 +1,57 @@
+"""remove empty filters
+
+Revision ID: afb7730f6a9c
+Revises: c5756bec8b47
+Create Date: 2018-06-07 09:52:54.535961
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'afb7730f6a9c'
+down_revision = 'c5756bec8b47'
+
+from alembic import op
+import json
+from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy import Column, Integer, Text
+
+from superset import db
+
+Base = declarative_base()
+
+
+class Slice(Base):
+    __tablename__ = 'slices'
+
+    id = Column(Integer, primary_key=True)
+    params = Column(Text)
+
+
+def upgrade():
+    bind = op.get_bind()
+    session = db.Session(bind=bind)
+
+    for slc in session.query(Slice).all():
+        try:
+            params = json.loads(slc.params)
+
+            for key in ('filters', 'having_filters', 'extra_filters'):
+                value = params.get(key)
+
+                # Remove empty in/not-in filters.
+                if value:
+                    params[key] = [
+                        x for x in value
+                        if not (x['op'] in ('in', 'not in') and not x['val'])
+                    ]
+
+            slc.params = json.dumps(params, sort_keys=True)
+        except Exception:
+            pass
+
+    session.commit()
+    session.close()
+
+
+def downgrade():
+    pass