db: auto-add missing model columns on startup (fix backupschedule.agent_id) (0.38.3)

create_all never ALTERs an existing table, so installs predating the
backupschedule.agent_id column kept the old schema and any ORM query
naming it failed with "no such column" — which the new fleet dashboard
(and the schedules list / scheduler loop) hit. init_db now diffs each
mapped table against the live schema and ADD COLUMNs the missing
nullable/defaulted ones. Idempotent and self-healing for similar drift.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/database.py

@@ -1,13 +1,17 @@
 """SQLModel database setup."""
 from __future__ import annotations
 
+import logging
 import os
 from collections.abc import Generator
 
+from sqlalchemy import inspect, text
 from sqlmodel import Session, SQLModel, create_engine
 
 from config import settings
 
+logger = logging.getLogger("stackpilot.database")
+
 os.makedirs(settings.DATA_DIR, exist_ok=True)
 _DB_PATH = os.path.join(settings.DATA_DIR, "stackpilot.db")
 _DB_URL = f"sqlite:///{_DB_PATH}"
@@ -19,11 +23,46 @@ engine = create_engine(
 )
 
 
+def _ensure_model_columns() -> None:
+    """Add columns that models define but a pre-existing table is missing.
+
+    ``SQLModel.create_all`` creates missing *tables* but never ALTERs an
+    existing one, so installs that predate a newly-added column keep the old
+    schema — and every ORM query that names the column fails with
+    ``OperationalError: no such column``. For each mapped table we diff the
+    model's columns against the live table and ``ADD COLUMN`` the safe
+    (nullable, or defaulted) ones. Idempotent: on a fresh DB create_all already
+    made every column, so this is a no-op.
+    """
+    insp = inspect(engine)
+    live_tables = set(insp.get_table_names())
+    with engine.begin() as conn:
+        for table_name, table in SQLModel.metadata.tables.items():
+            if table_name not in live_tables:
+                continue
+            existing = {c["name"] for c in insp.get_columns(table_name)}
+            for col in table.columns:
+                if col.name in existing:
+                    continue
+                # SQLite can only ADD a NOT NULL column if it has a default to
+                # backfill existing rows; skip the rest rather than crash.
+                if not col.nullable and col.default is None and col.server_default is None:
+                    logger.warning(
+                        "Cannot auto-add non-nullable column %s.%s (no default); "
+                        "manual migration needed", table_name, col.name
+                    )
+                    continue
+                ddl_type = col.type.compile(dialect=engine.dialect)
+                conn.execute(text(f'ALTER TABLE "{table_name}" ADD COLUMN "{col.name}" {ddl_type}'))
+                logger.info("Schema migration: added column %s.%s", table_name, col.name)
+
+
 def init_db() -> None:
     # Import models so they are registered on SQLModel.metadata.
     import models  # noqa: F401
 
     SQLModel.metadata.create_all(engine)
+    _ensure_model_columns()
 
 
 def get_session() -> Generator[Session, None, None]:

backend/version.py

@@ -1,3 +1,3 @@
 """Single source of truth for the StackPilot release version."""
 
-APP_VERSION = "0.38.2"
+APP_VERSION = "0.38.3"

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "stackpilot-frontend",
   "private": true,
-  "version": "0.38.2",
+  "version": "0.38.3",
   "type": "module",
   "scripts": {
     "dev": "vite",