Find where a Ruby method is defined and inspect its implementation; Method#source_location reveals file and line, while method_source can return the method body.

Making fixes in someone else’s GitHub repository is easier with modern open source tools, but pull requests and branch workflow still need care.

Move exact database records between systems by serializing Ruby objects with Marshal and Base64 when a direct export/import needs to preserve IDs and state.

Mailer previews often break when mailer code changes, and automated checks can catch missing updates before they reach development workflows.

Compile Webpacker assets once in parallel test runs and skip recompilation when files are unchanged, avoiding duplicate work and Capybara timeouts.

Paperclip attachments can collide across development, test, and parallel test processes when they share one storage tree. Separate environment-specific paths prevent overwritten files and missing test data.

Run Sidekiq jobs synchronously in development to avoid a separate worker process and benefit from code reloading.

Browser support in Webpacker depends on both Babel and UglifyJS; mismatched settings can break legacy browsers like IE11 even when JavaScript is transpiled.

A library for testing a Ruby gem against multiple Ruby, dependency and database combinations, with shared local and CI setup for full permutation coverage.

Bundler does not auto-require gems, so specs may miss dependencies unless the environment calls Bundler.require; direct dependencies still must be required by the gem itself.

Selenium browser tests see real system time unless the client clock is patched; timemachine.js and Timecop keep browser time aligned, while TZ can align the process time zone.

High-latency pagination queries can be reduced to one PostgreSQL statement by using COUNT(*) OVER() to return page rows and total rows together.

Remote Chrome debugging in Docker is awkward when integration tests need a browser you can inspect. SSH port forwarding can expose a local chromedriver inside the test container.

Ruby 1.8.7 test runs can fail with Gem::LOADED_SPECS_MUTEX NameError under older Bundler; Bundler 1.16.1 resolves it.

Forms can fail validation without visible feedback when the offending field has no input. A development-only error box keeps all form errors visible without leaving debug markup behind.

Passing arguments to Ruby’s block shorthand makes map(&:method) usable for nested lookup and JSON extraction without full block syntax.

RubyMine on Ubuntu can be installed as a snap with automatic updates or set up manually from the legacy archive. Configuration stays in ~/.config/JetBrains/RubyMine<version> with classic confinement.

includes can duplicate primary keys in ids when loading associated records, causing unexpected non-unique results; preload keeps the ids list stable.

Quickly gauge which database tables are growing unnoticed by checking approximate row counts in PostgreSQL or MySQL.

RSpec helper specs can leak content_for state between examples, making repeated checks fail. A fresh helper instance avoids stale instance variables.

Generate full url_for links only within selected view or controller blocks, with temporary opt-out and optional fixed host. Asset URLs remain unchanged.

Capybara has no built-in switch for disabling cookies in browser tests; a small Rack middleware can strip request cookies so scenarios can verify sign-in failures without them.

html_safe strings lose $1 and other match variables inside gsub blocks. A SafeBuffer override can restore access to capture groups during replacements.

unscope removes selected ActiveRecord scope constraints such as where and order, while unscoped returns an entirely unconstrained relation.