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Sarj Code Standards

store-mutation-command-fanout

Review per-field store mutations beside an existing model write command.

SARJ546 Rule source Tests Catalog JSON

Why

Per-field mutation entry points beside a model upsert can scatter write validation and concurrency policy. A smaller typed command surface makes those contracts easier to review together.

Fix

Review whether these methods can share a typed mutation command or internal write implementation. Preserve update-only and missing-row behavior, authorization, omission versus null, and guarded transitions. Do not replace a conditional UPDATE with an insert-capable upsert; model distinct transitions explicitly when they must stay separate.

Examples

Before — flagged Review a separate guarded setter
app/item_store.py
from psycopg import AsyncCursor




class ItemStore:
    def __init__(self, cursor: AsyncCursor):
        self.cursor = cursor


    async def upsert(self, item):
        await self.cursor.execute(
            "INSERT INTO item(id, name) VALUES(%s, %s) ON CONFLICT(id) DO UPDATE SET name=EXCLUDED.name",
            (item.id, item.name),
        )


    async def set_name_before_start(self, key, name):
        await self.cursor.execute(
            "UPDATE item SET name=%s WHERE id=%s AND started_at IS NULL", (name, key)
        )
After — preferred Different relation ownership is preserved
app/item_store.py
from psycopg import AsyncCursor




class ItemStore:
    def __init__(self, cursor: AsyncCursor):
        self.cursor = cursor


    async def upsert(self, item):
        await self.cursor.execute(
            "INSERT INTO item(id, name) VALUES(%s, %s) ON CONFLICT(id) DO UPDATE SET name=EXCLUDED.name",
            (item.id, item.name),
        )


    async def set_name_before_start(self, key, name):
        await self.cursor.execute(
            "UPDATE other SET name=%s WHERE id=%s AND started_at IS NULL", (name, key)
        )