fix: Make migration idempotent - check if columns exist before adding

app/alembic/versions/add_search_sites_columns.py

@@ -1,7 +1,7 @@
 """Add missing columns to search_sites table
 
 Revision ID: add_search_sites_columns
-Revises: merge_heads
+Revises: add_notification_channels
 Create Date: 2025-11-24
 
 """
@@ -9,6 +9,7 @@ from collections.abc import Sequence
 
 import sqlalchemy as sa
 from alembic import op
+from sqlalchemy import inspect
 
 # revision identifiers, used by Alembic.
 revision: str = "add_search_sites_columns"
@@ -17,33 +18,52 @@ branch_labels: str | Sequence[str] | None = None
 depends_on: str | Sequence[str] | None = None
 
 
+def column_exists(table_name: str, column_name: str) -> bool:
+    """Check if a column exists in a table."""
+    bind = op.get_bind()
+    inspector = inspect(bind)
+    columns = [col["name"] for col in inspector.get_columns(table_name)]
+    return column_name in columns
+
+
 def upgrade() -> None:
     """Add debug_enabled, price_selector, search_url, product_link_selector columns to search_sites."""
-    # Add debug_enabled column
-    op.add_column(
-        "search_sites",
-        sa.Column("debug_enabled", sa.Boolean(), server_default="false", nullable=False),
-    )
-    # Add price_selector column
-    op.add_column(
-        "search_sites",
-        sa.Column("price_selector", sa.String(), nullable=True),
-    )
-    # Add search_url column
-    op.add_column(
-        "search_sites",
-        sa.Column("search_url", sa.String(), nullable=True),
-    )
-    # Add product_link_selector column
-    op.add_column(
-        "search_sites",
-        sa.Column("product_link_selector", sa.String(), nullable=True),
-    )
+    # Add debug_enabled column (only if not exists)
+    if not column_exists("search_sites", "debug_enabled"):
+        op.add_column(
+            "search_sites",
+            sa.Column("debug_enabled", sa.Boolean(), server_default="false", nullable=False),
+        )
+
+    # Add price_selector column (only if not exists)
+    if not column_exists("search_sites", "price_selector"):
+        op.add_column(
+            "search_sites",
+            sa.Column("price_selector", sa.String(), nullable=True),
+        )
+
+    # Add search_url column (only if not exists)
+    if not column_exists("search_sites", "search_url"):
+        op.add_column(
+            "search_sites",
+            sa.Column("search_url", sa.String(), nullable=True),
+        )
+
+    # Add product_link_selector column (only if not exists)
+    if not column_exists("search_sites", "product_link_selector"):
+        op.add_column(
+            "search_sites",
+            sa.Column("product_link_selector", sa.String(), nullable=True),
+        )
 
 
 def downgrade() -> None:
     """Remove added columns from search_sites."""
-    op.drop_column("search_sites", "product_link_selector")
-    op.drop_column("search_sites", "search_url")
-    op.drop_column("search_sites", "price_selector")
-    op.drop_column("search_sites", "debug_enabled")
+    if column_exists("search_sites", "product_link_selector"):
+        op.drop_column("search_sites", "product_link_selector")
+    if column_exists("search_sites", "search_url"):
+        op.drop_column("search_sites", "search_url")
+    if column_exists("search_sites", "price_selector"):
+        op.drop_column("search_sites", "price_selector")
+    if column_exists("search_sites", "debug_enabled"):
+        op.drop_column("search_sites", "debug_enabled")