mmk dry-run

Preview what up or down would do — without ever touching the database.

mmk dry-run <up|down> [file] [options]

Usage

mmk dry-run up               # preview every pending migration that would apply
mmk dry-run up <file>        # preview a single file
mmk dry-run down             # preview reverting the last batch
mmk dry-run down --steps <n> # preview reverting the last N migrations

How it works

dry-run resolves exactly the same set of files the real command would, and prints the plan — but it never connects for writes, acquires no lock, and changes nothing. It's the safe way to confirm a production run before committing to it.

◎ Dry-run  Would apply 2 migrations:
   • 20260605120000-add-users-index.js
   • 20260605120500-backfill-status.js

Options

Option	Description
up | down	Required. Direction to preview.
[file]	Preview a single migration file.
--steps <n>	(down only) Preview reverting the last N migrations. Ignored for up.
--json	Emit the planned rows as JSON.

Plus the global flags.

Read-only

Because a dry-run never writes, it takes no concurrency lock and is always safe to run against production.