IRB’s multi-line completion can slow down input and make Backspace unreliable; --nomultiline or IRB.conf[:USE_MULTILINE] = false disables it while keeping Tab completion.

makandra_sidekiq 0.2.0 prevents Sidekiq from killing long-running jobs during shutdown by honoring the configured timeout and allowing jobs to requeue safely.

Reliable file-download testing in Capybara, including filename, content type, disposition, and text inspection across Selenium and Rack::Test without leaving the page.

Chrome and Safari consoles expose the selected DOM node, making Angular scope inspection fast when debugging selected page elements.

RSpec partial double verification blocks stubbing helper methods that come from Rails controllers; without_partial_double_verification or a spec config can disable it temporarily.

Changing RubyGems or Bundler versions on servers can leave deployed gems and binstubs incompatible; clearing the shared bundle path forces reinstall and avoids boot failures.

Relative asset URLs can work in Rails development but break after assets:precompile, because files are merged into public/assets and fingerprinted.

pre blocks can break out of nested flex layouts because flex items default to min-width: auto, causing overflowing code boxes and broken layouts.

ES2021 adds safer global string replacement, Promise.any(), logical assignment operators, numeric separators and WeakRef support in modern browsers.

Rails apps with multiple databases need separate test cleanup, or records bleed between specs and migrations. DatabaseCleaner can target each connection via a model-backed database key.

attribute? often checks presence like attribute.present?, but numeric values and associations behave differently; 0 can be false for ActiveRecord query attributes.

Unpoly event listeners can be limited to a single execution with { once: true } or up.off, useful for tests and callbacks that must not repeat.

Inspect registered DOM event handlers in Chrome DevTools with getEventListeners(object) or the Event Listeners tab when debugging missing or duplicate listeners.

Need version or install-path details for a Ruby gem? gem info and Gem.loaded_specs provide gem metadata at the command line or during runtime.

Merge requests are often rejected for avoidable issues: missing tests, debug code, UI defects, slow queries, missing indexes, or incomplete database changes.

Shared data in threaded Ruby code needs protection or immutability; concurrent-ruby offers thread-safe Array and Hash, and Hamster uses immutable collections.

Query strings are easier to read and modify with URLSearchParams; it parses, updates, removes, and checks parameters across modern browsers, except IE 11.

Inspect Rails emails in a real mail app by exporting a Mail::Message to .eml and opening it, instead of relying only on browser previews.

Jasmine boot failures can stem from browser/module detection issues, causing jasmineRequire or getJasmineRequireObj() errors in Webpacker and esbuild setups.

Auto-growing text inputs need a textarea-based workaround because normal inputs cannot wrap; autosize makes the field expand and shrink with its content.

Cast ActiveRecord instances or relations to ActiveType::Record subclasses for safer behavior than ActiveRecord#becomes and consistent typed access.