add blocker presets

backend/app/db.py

@@ -11,7 +11,7 @@ from __future__ import annotations
 from collections.abc import Iterator
 from contextlib import contextmanager
 
-from sqlalchemy import create_engine
+from sqlalchemy import create_engine, inspect, text
 from sqlalchemy.orm import DeclarativeBase, Session, sessionmaker
 
 from app.config import env_settings
@@ -32,11 +32,36 @@ engine = create_engine(env_settings().database_url, **_engine_kwargs(env_setting
 SessionLocal = sessionmaker(bind=engine, autoflush=False, expire_on_commit=False)
 
 
+# Columns a refactor later dropped from the model but, with no migration tool
+# in this project, left behind on any database that was already running —
+# still `NOT NULL` with no server-side default, so every insert that no
+# longer sets them fails. `create_all` only ever adds; this is the other half.
+_DEAD_COLUMNS: dict[str, tuple[str, ...]] = {
+    "tasks": ("completed_here",),
+}
+
+
+def _drop_dead_columns() -> None:
+    inspector = inspect(engine)
+    existing_tables = set(inspector.get_table_names())
+    with engine.begin() as conn:
+        for table, columns in _DEAD_COLUMNS.items():
+            if table not in existing_tables:
+                continue
+            existing_columns = {c["name"] for c in inspector.get_columns(table)}
+            for column in columns:
+                if column in existing_columns:
+                    conn.execute(text(f'ALTER TABLE {table} DROP COLUMN {column}'))
+
+
 def init_db() -> None:
-    """Create any missing tables. The schema is additive, so this is enough."""
+    """Create any missing tables. The schema is additive, so this is enough —
+    plus the one-time cleanup above for columns a refactor removed from the
+    model."""
     from app import models  # noqa: F401  (register the mappers)
 
     Base.metadata.create_all(bind=engine)
+    _drop_dead_columns()
 
 
 @contextmanager