Rails: migrations are not applied

What it means

The database schema is behind the code.

The build passed, but the app did not start or did not answer the health check.

Typical causes

• The app does not listen on 0.0.0.0 and the port from the PORT variable
• An environment variable is missing, or the database or Redis is not connected
• The start command is wrong or the process exits right away

How to fix it on mevcore

Run migrations before the start: «bin/rails db:prepare && bin/rails server …» in the start command in the settings, or once on the «Terminal» tab.

1. 1 Open the app in the mevcore panel: the Problems card on the overview shows this error and the log line it was found in.
2. It is fixed on the “Settings” tab of the app.
3. 2 After the fix, deploy again. If it fails again, the log ends with [mevcore] lines naming the new error code.
4. 3 The "Ask AI" button next to the error prepares a request for ChatGPT or Claude: the error code, the end of the log without secrets and the app settings.

For an AI assistant

The same in English: paste it together with the log into the AI chat.

mevcore error code: runtime.rails_pending_migration
phase: start / health check
diagnosis: Rails: migrations are not applied
platform hint: The database schema is behind the code. Run migrations before the start: «bin/rails db:prepare && bin/rails server …» in the start command in the settings, or once on the «Terminal» tab.
platform docs: https://mevcore.com/llms-full.txt

Related errors

• runtime.migration_table_exists A migration creates a table that exists
• runtime.rails_master_key Rails cannot decrypt its credentials
• runtime.rails_blocked_host Rails blocks the host <host>
• runtime.prisma_migration_failed A Prisma migration failed