Lint rules

The linter analyzes migration plans before execution and warns about dangerous patterns.

Usage

npx @smplcty/schema-flow lint --db postgresql://user:pass@localhost:5432/mydb

Rules

Rule	Severity	Description
set-not-null-direct	Warning	Direct SET NOT NULL without the safe CHECK pattern. Can lock the table for a full scan.
add-column-with-default	Warning	Adding a column with a volatile default. May lock the table on older PostgreSQL versions.
drop-column	Warning	Dropping a column causes data loss.
drop-table	Warning	Dropping a table causes data loss.
type-narrowing	Warning	Narrowing a column type (e.g., text -> varchar(50)) can fail if existing data doesn’t fit.
type-change	Warning	Changing column type may require a full table rewrite.
missing-fk-index	Info	Foreign key column without an index. Causes slow joins and slow cascading deletes.
rename-detection	Info	Detected a possible rename (drop + add with same type). Consider using expand/contract instead.

Programmatic API

import { lintPlan } from '@smplcty/schema-flow';

const result = lintPlan(plan);

for (const warning of result.warnings) {
  console.log(`[${warning.severity}] ${warning.rule}: ${warning.message}`);
  // warning.operation — the operation that triggered the warning
}