Split tags migration (#7002)

This PR removes the iteration over charts, dashboards and saved queries to create tags in the original migration, leaving only the logic to create the tags and the tagged objects tables.
Tested locally by running `superset db downgrade` to revert to the previous migration and then running `superset db upgrade` to the current version.

superset/migrations/versions/c82ee8a39623_add_implicit_tags.py

@@ -27,16 +27,11 @@
 down_revision = 'c617da68de7d'
 
 from alembic import op
-import sqlalchemy as sa
-from sqlalchemy import Column, Enum, Integer, ForeignKey, String, Table
+from sqlalchemy import Column, Enum, Integer, ForeignKey, String
 from sqlalchemy.ext.declarative import declarative_base
-from sqlalchemy.orm import relationship
 
-from superset import db
 from superset.models.helpers import AuditMixinNullable
 from superset.models.tags import (
-    get_object_type,
-    get_tag,
     ObjectTypes,
     TagTypes,
 )
@@ -69,134 +64,11 @@ class User(Base):
     id = Column(Integer, primary_key=True)
 
 
-slice_user = Table(
-    'slice_user',
-    Base.metadata,
-    Column('id', Integer, primary_key=True),
-    Column('user_id', Integer, ForeignKey('ab_user.id')),
-    Column('slice_id', Integer, ForeignKey('slices.id'))
-)
-
-
-dashboard_user = Table(
-    'dashboard_user',
-    Base.metadata,
-    Column('id', Integer, primary_key=True),
-    Column('user_id', Integer, ForeignKey('ab_user.id')),
-    Column('dashboard_id', Integer, ForeignKey('dashboards.id'))
-)
-
-
-class Slice(Base, AuditMixinNullable):
-    """Declarative class to do query in upgrade"""
-    __tablename__ = 'slices'
-
-    id = Column(Integer, primary_key=True)
-    owners = relationship("User", secondary=slice_user)
-
-
-class Dashboard(Base, AuditMixinNullable):
-    """Declarative class to do query in upgrade"""
-    __tablename__ = 'dashboards'
-    id = Column(Integer, primary_key=True)
-    owners = relationship("User", secondary=dashboard_user)
-
-
-class SavedQuery(Base):
-    __tablename__ = 'saved_query'
-    id = Column(Integer, primary_key=True)
-    user_id = Column(Integer, ForeignKey('ab_user.id'))
-
-
-class Favstar(Base):
-    __tablename__ = 'favstar'
-    id = Column(Integer, primary_key=True)
-    user_id = Column(Integer, ForeignKey('ab_user.id'))
-    class_name = Column(String(50))
-    obj_id = Column(Integer)
-
-
 def upgrade():
     bind = op.get_bind()
-    session = db.Session(bind=bind)
-
     Tag.__table__.create(bind)
     TaggedObject.__table__.create(bind)
 
-    # add type tags (eg, `type:dashboard` for dashboards)
-    for type in ObjectTypes.__members__:
-        session.add(Tag(name='type:{0}'.format(type), type=TagTypes.type))
-
-    # add owner tags (eg, `owner:1` for things owned by the admin)
-    for chart in session.query(Slice):
-        for owner in chart.owners:
-            name = 'owner:{0}'.format(owner.id)
-            tag = get_tag(name, session, TagTypes.owner)
-            tagged_object = TaggedObject(
-                tag_id=tag.id,
-                object_id=chart.id,
-                object_type=ObjectTypes.chart,
-            )
-            session.add(tagged_object)
-
-        tag = get_tag('type:chart', session, TagTypes.type)
-        tagged_object = TaggedObject(
-            tag_id=tag.id,
-            object_id=chart.id,
-            object_type=ObjectTypes.chart,
-        )
-        session.add(tagged_object)
-
-    for dashboard in session.query(Dashboard):
-        for owner in dashboard.owners:
-            name = 'owner:{0}'.format(owner.id)
-            tag = get_tag(name, session, TagTypes.owner)
-            tagged_object = TaggedObject(
-                tag_id=tag.id,
-                object_id=dashboard.id,
-                object_type=ObjectTypes.dashboard,
-            )
-            session.add(tagged_object)
-
-        tag = get_tag('type:dashboard', session, TagTypes.type)
-        tagged_object = TaggedObject(
-            tag_id=tag.id,
-            object_id=dashboard.id,
-            object_type=ObjectTypes.dashboard,
-        )
-        session.add(tagged_object)
-
-    for query in session.query(SavedQuery):
-        name = 'owner:{0}'.format(query.user_id)
-        tag = get_tag(name, session, TagTypes.owner)
-        tagged_object = TaggedObject(
-            tag_id=tag.id,
-            object_id=query.id,
-            object_type=ObjectTypes.query,
-        )
-        session.add(tagged_object)
-
-        tag = get_tag('type:query', session, TagTypes.type)
-        tagged_object = TaggedObject(
-            tag_id=tag.id,
-            object_id=query.id,
-            object_type=ObjectTypes.query,
-        )
-        session.add(tagged_object)
-
-    # add favorited_by tags
-    for star in session.query(Favstar):
-        name = 'favorited_by:{0}'.format(star.user_id)
-        tag = get_tag(name, session, TagTypes.favorited_by)
-        tagged_object = TaggedObject(
-            tag_id=tag.id,
-            object_id=star.obj_id,
-            object_type=get_object_type(star.class_name),
-        )
-        session.add(tagged_object)
-
-    session.commit()
-
 
 def downgrade():
     op.drop_table('tag')