fix(sql lab): deleting the last saved query or the last executed from…

… history (#19225)

* fix: fix issue when deleting the last saved query or the last executed query

* merge migration

superset/migrations/versions/58df9d617f14_add_on_saved_query_delete_tab_state_.py

@@ -0,0 +1,66 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+"""add_on_saved_query_delete_tab_state_null_constraint"
+
+Revision ID: 58df9d617f14
+Revises: 6766938c6065
+Create Date: 2022-03-16 23:24:40.278937
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = "58df9d617f14"
+down_revision = "6766938c6065"
+
+import sqlalchemy as sa
+from alembic import op
+
+from superset.utils.core import generic_find_fk_constraint_name
+
+
+def upgrade():
+    bind = op.get_bind()
+    insp = sa.engine.reflection.Inspector.from_engine(bind)
+
+    with op.batch_alter_table("tab_state") as batch_op:
+        batch_op.drop_constraint(
+            generic_find_fk_constraint_name("tab_state", {"id"}, "saved_query", insp),
+            type_="foreignkey",
+        )
+
+        batch_op.create_foreign_key(
+            "saved_query_id",
+            "saved_query",
+            ["saved_query_id"],
+            ["id"],
+            ondelete="SET NULL",
+        )
+
+
+def downgrade():
+    bind = op.get_bind()
+    insp = sa.engine.reflection.Inspector.from_engine(bind)
+
+    with op.batch_alter_table("tab_state") as batch_op:
+        batch_op.drop_constraint(
+            generic_find_fk_constraint_name("tab_state", {"id"}, "saved_query", insp),
+            type_="foreignkey",
+        )
+
+        batch_op.create_foreign_key(
+            "saved_query_id", "saved_query", ["saved_query_id"], ["id"],
+        )

superset/models/sql_lab.py

@@ -291,7 +291,9 @@ class TabState(Model, AuditMixinNullable, ExtraJSONMixin):
     hide_left_bar = Column(Boolean, default=False)
 
     # any saved queries that are associated with the Tab State
-    saved_query_id = Column(Integer, ForeignKey("saved_query.id"), nullable=True)
+    saved_query_id = Column(
+        Integer, ForeignKey("saved_query.id", ondelete="SET NULL"), nullable=True
+    )
     saved_query = relationship("SavedQuery", foreign_keys=[saved_query_id])
 
     def to_dict(self) -> Dict[str, Any]:

superset/views/sql_lab.py

@@ -20,6 +20,7 @@
 from flask_appbuilder.models.sqla.interface import SQLAInterface
 from flask_appbuilder.security.decorators import has_access, has_access_api
 from flask_babel import lazy_gettext as _
+from sqlalchemy import and_
 
 from superset import db, is_feature_enabled
 from superset.constants import MODEL_VIEW_RW_METHOD_PERMISSION_MAP, RouteMethod
@@ -228,6 +229,29 @@ def migrate_query(  # pylint: disable=no-self-use
     def delete_query(  # pylint: disable=no-self-use
         self, tab_state_id: int, client_id: str
     ) -> FlaskResponse:
+        # Before deleting the query, ensure it's not tied to any
+        # active tab as the last query. If so, replace the query
+        # with the latest one created in that tab
+        tab_state_query = db.session.query(TabState).filter_by(
+            id=tab_state_id, latest_query_id=client_id
+        )
+        if tab_state_query.count():
+            query = (
+                db.session.query(Query)
+                .filter(
+                    and_(
+                        Query.client_id != client_id,
+                        Query.user_id == g.user.get_id(),
+                        Query.sql_editor_id == str(tab_state_id),
+                    ),
+                )
+                .order_by(Query.id.desc())
+                .first()
+            )
+            tab_state_query.update(
+                {"latest_query_id": query.client_id if query else None}
+            )
+
         db.session.query(Query).filter_by(
             client_id=client_id,
             user_id=g.user.get_id(),