Use SQLAlchemy expressions for is_deleted migration backup

api/migrations/versions/2025_09_02_2012-4f02b6704509_remove_unused_is_deleted_field_from_.py

@@ -4,8 +4,8 @@ Revision ID: 4f02b6704509
 Revises: 7bb281b7a422
 Create Date: 2025-09-02 20:12:37.311318
 
-This migration runs on both PostgreSQL and MySQL. Avoid hard‑coding boolean
-literals so the SQL renders correctly for each dialect.
+This migration runs on both PostgreSQL and MySQL. It uses SQLAlchemy
+expressions instead of raw SQL so dialects handle boolean literals.
 """
 from alembic import op
 import models as models
@@ -25,19 +25,35 @@ backup_table_name = 'conversations_4f02b6704509_bak'
 
 def upgrade():
     # ### commands auto generated by Alembic - please adjust! ###
-    # Create backup table for soft-deleted conversations
     context = op.get_context()
-    dialect = context.dialect.name if hasattr(context, "dialect") else op.get_bind().dialect.name
-    true_literal = "1" if dialect == "mysql" else "TRUE"
+    if context.is_offline_mode():
+        # In offline mode we cannot reflect columns; skip backup/data moves.
+        with op.batch_alter_table('conversations', schema=None) as batch_op:
+            batch_op.drop_column('is_deleted')
+        return
 
-    # Create backup table with all soft-deleted conversations (works even if zero rows)
-    op.execute(sa.text(f"""
-        CREATE TABLE {backup_table_name} AS
-        SELECT * FROM conversations WHERE is_deleted = {true_literal}
-    """))
+    bind = op.get_bind()
+    metadata = sa.MetaData()
+    conversations = sa.Table('conversations', metadata, autoload_with=bind)
 
-    # Delete soft-deleted conversations from main table
-    op.execute(sa.text(f"DELETE FROM conversations WHERE is_deleted = {true_literal}"))
+    # Drop leftover backup table if it exists (idempotent reruns)
+    inspector = inspect(bind)
+    if backup_table_name in inspector.get_table_names():
+        op.drop_table(backup_table_name)
+
+    # Create backup table with identical schema
+    op.create_table(backup_table_name, *[col.copy() for col in conversations.columns])
+    backup_table = sa.Table(backup_table_name, metadata, autoload_with=bind)
+
+    # Copy soft-deleted rows into backup
+    insert_backup = sa.insert(backup_table).from_select(
+        conversations.columns.keys(),
+        sa.select(*conversations.c).where(conversations.c.is_deleted.is_(sa.true())),
+    )
+    bind.execute(insert_backup)
+
+    # Delete soft-deleted rows from main table
+    bind.execute(sa.delete(conversations).where(conversations.c.is_deleted.is_(sa.true())))
 
     with op.batch_alter_table('conversations', schema=None) as batch_op:
         batch_op.drop_column('is_deleted')
@@ -51,25 +67,24 @@ def downgrade():
         batch_op.add_column(sa.Column('is_deleted', sa.BOOLEAN(), server_default=sa.text('false'), autoincrement=False, nullable=False))
 
     # Restore soft-deleted conversations from backup table if it exists
-
-    # Check if backup table exists using inspector (works for all database types)
-    bind = op.get_bind()
-    if bind is None:
-        # Offline migration generation; skip data restoration logic
+    context = op.get_context()
+    if context.is_offline_mode():
         return
-    dialect = bind.dialect.name
-    true_literal = "1" if dialect == "mysql" else "TRUE"
+
+    bind = op.get_bind()
+    metadata = sa.MetaData()
     inspector = inspect(bind)
-    existing_tables = inspector.get_table_names()
 
-    if backup_table_name in existing_tables:
-        # Restore the soft-deleted conversations
-        op.execute(sa.text(f"""
-            INSERT INTO conversations
-            SELECT * FROM {backup_table_name}
-        """))
+    if backup_table_name in inspector.get_table_names():
+        conversations = sa.Table('conversations', metadata, autoload_with=bind)
+        backup_table = sa.Table(backup_table_name, metadata, autoload_with=bind)
 
-        # Drop the backup table after restoration
-        op.execute(sa.text(f"DROP TABLE {backup_table_name}"))
+        restore_stmt = sa.insert(conversations).from_select(
+            conversations.columns.keys(),
+            sa.select(*backup_table.c),
+        )
+        bind.execute(restore_stmt)
+
+        op.drop_table(backup_table_name)
 
     # ### end Alembic commands ###