orm-preflight MCP server

orm-preflight

Preflight safety checks for TypeORM migrations: catch data loss and locking before you merge.

Documentation: https://sikandar100.github.io/orm-preflight/

Changing a column's length in TypeORM can delete all of its data. When a column's type or length changes, TypeORM's migration generator drops the column and adds it again (typeorm/typeorm#3357). The migration looks harmless in review and passes every test on an empty database. orm-preflight catches that, and other migrations that lose data, lock busy tables, or break a rolling deploy, before you merge.

src/migrations/1727100000000-WidenUserName.ts
  7:30  error  no-drop-and-recreate-column
        "users"."name" is dropped and re-added in the same migration. Every existing value in this column will be lost.
        Why:  TypeORM drops and re-adds a column when its type or length changes, instead of changing it in place. The new column starts empty.
        Safe: Change the type in place: ALTER TABLE "users" ALTER COLUMN "name" TYPE varchar(255). Widening a varchar, or changing varchar to text, does not rewrite the table. ...
        Docs: https://github.com/sikandar100/orm-preflight/blob/main/docs/rules/no-drop-and-recreate-column.md

  8:30  error  no-add-not-null-without-default
        "users"."name" is added as NOT NULL without a default. The migration fails as soon as "users" has any rows.
        ...

2 errors, 0 warnings in 1 migration

Install and run

npm install --save-dev orm-preflight
npx orm-preflight "src/migrations/*.ts"

Node.js 20 or newer. Without arguments, orm-preflight checks the migrations globs from its config, or every migrations folder in the project.

To start on an existing project without fixing its history, run npx orm-preflight init first (see Adopting on an existing project).

What it catches

Shortened. The full README is on GitHub.