thoughtbot/shoulda-matchers · error · NonCaseSwappableValueError

Your #{model.name} model has a uniqueness validation on :#{a

Error message

Your #{model.name} model has a uniqueness validation on :#{attribute} which is
declared to be case-sensitive, but the value the uniqueness matcher used,
#{value.inspect}, doesn't contain any alpha characters, so using it to
test the case-sensitivity part of the validation is ineffective. There are
two possible solutions for this depending on what you're trying to do here:

a) If you meant for the validation to be case-sensitive, then you need to give
   the uniqueness matcher a saved instance of #{model.name} with a value for
   :#{attribute} that contains alpha characters.

b) If you meant for the validation to be case-insensitive, then you need to
   add `case_sensitive: false` to the validation and add `case_insensitive` to
   the matcher.

For more information, please see:

https://matchers.shoulda.io/docs/v#{Shoulda::Matchers::VERSION}/file.NonCaseSwappableValueError.html

What it means

Error "Your #{model.name} model has a uniqueness validation on :#{attribute} which is declared to be case-sensitive, but the value the uniqueness matcher used, #{value.inspect}, doesn't contain any alpha characters, so using it to test the case-sensitivity part of the validation is ineffective. There are two possible solutions for this depending on what you're trying to do here: a) If you meant for the validation to be case-sensitive, then you need to give the uniqueness matcher a saved instance of #{model.name} with a value for :#{attribute} that contains alpha characters. b) If you meant for the validation to be case-insensitive, then you need to add `case_sensitive: false` to the validation and add `case_insensitive` to the matcher. For more information, please see: https://matchers.shoulda.io/docs/v#{Shoulda::Matchers::VERSION}/file.NonCaseSwappableValueError.html" thrown in thoughtbot/shoulda-matchers.

Source

Thrown at lib/shoulda/matchers/active_record/validate_uniqueness_of_matcher.rb:750

        def does_not_match_uniqueness_without_scopes?
          @failure_reason = nil

          if existing_value_read.blank?
            update_existing_record!(arbitrary_non_blank_value)
          end

          allows_value_of(existing_value_read, @expected_message)
        end

        def matches_uniqueness_with_case_sensitivity_strategy?
          if should_test_case_sensitivity?
            value = existing_value_read
            swapcased_value = value.swapcase

            if case_sensitivity_strategy == :sensitive
              if value == swapcased_value
                raise NonCaseSwappableValueError.create(
                  model:,
                  attribute: @attribute,
                  value:,
                )
              end

              allows_value_of(swapcased_value, @expected_message)
            else
              disallows_value_of(swapcased_value, @expected_message)
            end
          else
            true
          end
        end

        def does_not_match_uniqueness_with_case_sensitivity_strategy?
          if should_test_case_sensitivity?
            @failure_reason = nil

View on GitHub (pinned to 79cdfbc326)

When it happens

Trigger: Thrown at lib/shoulda/matchers/active_record/validate_uniqueness_of_matcher.rb:750 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of thoughtbot/shoulda-matchers@79cdfbc326 (2026-08-23). Data as JSON: /api/errors/058163b799b12511. Report an issue: GitHub.