Hey, Emmanuel Hayford here with the latest from the Rails codebase. Let’s get to it!

Oh! In case you missed it, all the talks from #RailsWorld 2025 are now available online here.

Fix SCRIPT_NAME handling for engines mounted at root.
When an engine is mounted at / and SCRIPT_NAME is in use, URL helpers were incorrectly dropping the script name from generated URLs. The issue was traced to RoutesProxy#merge_script_names, which didn’t handle the edge case where the script name was just /. The fix trims trailing slashes from new_script_name, restoring correct URL generation for apps deployed under a path prefix.

Generalize :rich_text_area Capybara selector
The :rich_text_area Capybara selector no longer depends on a <trix-editor> element and instead looks for role="textbox" and contenteditable attributes. This change makes it easier to support other Action Text–capable WYSIWYG editors. The fill_in_rich_textarea test helper was also updated to use the .value property on <trix-editor> (available since trix v2.1.7) before falling back to editor.loadHTML().

Show engine routes in /rails/info/routes
Engine routes are now displayed in /rails/info/routes alongside application routes. Previously, only the main application routes were shown because _routes.routes excluded engine routes. This change uses Rails.application.routes.routes, ensuring that mounted engines appear in the routes output as well.

Restore Active Storage config to disable variants and analyzers
Active Storage now lets you fully configure which analyzers and variant processor to use. You can clear out analyzers entirely or provide your own:

# ActiveStorage.analyzers can be set to an empty array:
config.active_storage.analyzers = []
# => ActiveStorage.analyzers = []

# or use custom analyzer:
config.active_storage.analyzers = [ CustomAnalyzer ]
# => ActiveStorage.analyzers = [ CustomAnalyzer ]

If no configuration is provided, it will use the default analyzers.

You can also disable variant processor to remove warnings on startup about missing gems.

config.active_storage.variant_processor = :disabled

Fix time attribute dirty tracking with timezone conversions
Time-only attributes could be incorrectly marked as changed when assigning the same time, due to timezone conversions shifting the hidden date part. The fix normalizes time values to a fixed date (2000-01-01) during conversions, preventing false dirty tracking while leaving datetime attributes unchanged.

Before (Bug)

  # Configuration
  Time.zone = "Tokyo"
  ActiveRecord.default_timezone = :utc

  user = User.create!(created_at: "14:30")
  user.reload

  user.created_at = "14:30"
  user.changed_attribute_names_to_save
  # => ["created_at"] # Incorrectly marked as changed!

After (Fixed)

  # Configuration
  config.active_record.use_fixed_date_for_time_attributes = true

  user = User.create!(created_at: "14:30")
  user.reload

  user.created_at = "14:30"
  user.changed_attribute_names_to_save
  # => [] # Correctly not marked as changed

RateLimiting: support method names for :by and :with
Prior to this commit, :by and :with options only supported callables. This commit aims to bring rate limiting closer in parity to callbacks declarations like before_action and after_action by supporting instance method names as well.

Without this change, multi-line customized callables can make declarations difficult to read. Similarly, shared customization would require a local variable to be re-used. For example:

  rate_limiting_bucket = -> { ... }

  rate_limit to: 3, within: 1.minutes, by: rate_limiting_bucket
  rate_limit to: 10, within: 5.minutes, by: rate_limiting_bucket
  rate_limit to: 30, within: 10.minutes,
    by: -> {
      # ...
      # multiple lines
      # ...
    },
    with: -> {
      # ...
      # multiple lines
      # ...
    }

You can view the whole list of changes here. We had 22 contributors to the Rails codebase this past week!

Until next time!

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