fix(migration): handle existing contact_id column in mails table

alembic/versions/0027_unify_company_to_contact.py

@@ -38,10 +38,16 @@ def upgrade():
     )
     # Rename company_id to contact_id in mails (if column exists)
     conn = op.get_bind()
-    result = conn.execute(
+    has_company_id = conn.execute(
         sa.text("SELECT 1 FROM information_schema.columns WHERE table_name='mails' AND column_name='company_id'")
     ).fetchone()
-    if result:
+    has_contact_id = conn.execute(
+        sa.text("SELECT 1 FROM information_schema.columns WHERE table_name='mails' AND column_name='contact_id'")
+    ).fetchone()
+    if has_company_id and has_contact_id:
+        # Both columns exist: drop company_id (contact_id already present)
+        op.drop_column("mails", "company_id")
+    elif has_company_id:
         op.alter_column("mails", "company_id", new_column_name="contact_id")
 
 
@@ -62,10 +68,13 @@ def downgrade():
     op.execute(
         "UPDATE addresses SET entity_type = 'company' WHERE entity_type = 'contact'"
     )
-    # Rename contact_id back to company_id in mails
+    # Rename contact_id back to company_id in mails (only if contact_id exists and company_id doesn't)
     conn = op.get_bind()
-    result = conn.execute(
+    has_contact_id = conn.execute(
         sa.text("SELECT 1 FROM information_schema.columns WHERE table_name='mails' AND column_name='contact_id'")
     ).fetchone()
-    if result:
+    has_company_id = conn.execute(
+        sa.text("SELECT 1 FROM information_schema.columns WHERE table_name='mails' AND column_name='company_id'")
+    ).fetchone()
+    if has_contact_id and not has_company_id:
         op.alter_column("mails", "contact_id", new_column_name="company_id")