During a recent (and first) upgrade of Rails to 7.0, I found a lot of changes in the schema.rb file.

There is the self explanatory one: add versioning to the schema file.

And the noisy change of every single datatime field's precision attribute.

Looking at this, I find out that the precision default to 6. It explains why some attributes got precision: nil and some other got their precision: 6 removed.

https://github.com/rails/rails/blob/aed8feae3b7a3f7df59de69355cc3bda1d5479d6/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb#L1322

This was a change made in 2019 and released from Rails 7.0 in December 2021. So, 2.5 years after but I'm happy to discover that and sharing it.

https://github.com/rails/rails/commit/57015cdfa2083351f64a82f7566965172a41efcb#diff-868f1dccfcbed26a288bf9f3fd8a39c863a4413ab0075e12b6805d9798f556d1R714-R716

For people following here, Rails 7.1 is already planned and is already passing the entire test suite. Hopefully, it won't take long.

Cheers!