Graphql-engine: Use ADD COLUMN "IF NOT EXISTS" when generating up migrations

[AdityaAnand1]

Right now, the up migrations are not idempotent. This is one such example.

When adding a column, simply add it only if it doesn't exist, otherwise do nothing (= migration has already been run)

[GrizliK1988]

Hi!

I'd like to contribute to this issue.

[GrizliK1988]

Hi!

PR is ready https://github.com/hasura/graphql-engine/pull/5895

[beerose]

Hi @AdityaAnand1,

Thanks for the report. However, we don't want to make migrations idempotent by default. It's because they become less strict this way.
Let's say someone added a column directly with psql with a different data type. ADD COLUMN IF NOT EXISTS ... migration will succeed, but the Hasura migrations won't reflect the state of the system. You can consider adding IF EXISTS / IF NOT EXISTS manually.

I'm therefore closing this issue.

[GrizliK1988]

Thanks @beerose ! Yeah, it's fine, was a good opportunity to get into hasura :)