[aitorlb]

Ticket: CASE-4454

Problem

On PostgreSQL, a unique violation on a table that the current role is subject to row-level security on carries no DETAIL: Key (...)=(...) already exists. line. PostgreSQL omits it because the values could belong to a row the role cannot see.

PostgresqlAdapter.unique_error_columns does error.message[/Key \((.+)\)=/, 1].split(', '), so the missing line makes it call split on nil. validates_db_uniqueness_of then raises NoMethodError: undefined method 'split' for nil where it should add the validation error. It only happens on the path this gem exists for: two writers pass validation and the index decides.

Fix

error.message[/Key \((.+)\)=/, 1]&.split(', ')

Rescuer builds two keys for a unique violation, one from the columns and one from the index name, and UniquenessKeyExtractor.attribute_by_key registers every validator under both. The index name is still in the message (duplicate key value violates unique constraint "..."), so returning nil is enough. The MySQL adapter already returns nil from unique_error_columns and relies on the same thing.

Tests

• spec/validations/validates_db_uniqueness_of_row_level_security_spec.rb: a table with row-level security enabled, run as a role that is not a superuser (a superuser bypasses RLS and keeps the detail line). It covers an attribute-only validator, a scoped validator and an index_name: validator, each through create and create!. A first example asserts the error really has no Key ( line, so it fails if PostgreSQL changes.
• spec/adapters/postgresql_unique_error_columns_spec.rb: the adapter method with and without the detail line.

Without the change, 7 of the 9 new examples fail with undefined method 'split' for nil; with it all 9 pass. The existing PostgreSQL examples still pass (166 in validates_db_uniqueness_of_spec.rb, 25 in the presence and belongs-to specs), and RuboCop is clean with the repo config.

The new RLS spec creates and drops a role, so it needs a database user that can create roles (CI's root can). It skips otherwise.

Not run

MySQL and SQLite: the gems were not available where I ran this. The change touches only the PostgreSQL adapter.

Found while testing PostgreSQL row-level security on toptal/career-services-backend, where 7 specs hit this.

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