There are two failure modes and teams pick one without deciding. Either nobody updates anything until a CVE forces a jump across four major versions in a week, or Dependabot opens eleven PRs

Every B2B application eventually needs tenant isolation, and the decision gets made early — usually by whoever writes the first migration, usually without a discussion. Three months later you find out whether it

Every one of these ships to production regularly, and none of them are signs that someone is a bad developer. They’re mistakes Rails makes easy — the framework optimises for getting something working

user&.profile&.address&.city looks defensive and reads as careful code. It’s also a sentence that says “I don’t know which of these can be nil, so I’ve assumed all of them can” — and when

Your form markup is forty lines per field: a label, an input, a conditional error span, three utility classes, an aria attribute someone added once. Multiply by eleven fields and six forms and

Someone asks for help and you paste forty lines into Slack. It wraps at column sixty, loses its indentation, and scrolls off the channel in an hour. Or you paste a screenshot of

Someone adds RuboCop to a six-year-old Rails app, runs it, and gets 47,000 offences. The obvious next move — rubocop -A and commit — produces a diff touching every file in the repository,

There’s a stage in every text-parsing problem where the regex stops being the right tool. You’ve got a pattern with four alternations and three lookaheads, it’s slow, it’s unreadable, and it still can’t

uninitialized constant Billing::PDFGenerator on a file that unmistakably exists at app/services/billing/pdf_generator.rb. Or a class that loads fine in development and vanishes in production. Or a change to a model that doesn’t take effect

A pre-commit hook that runs your full test suite gets bypassed with --no-verify within a week, and then it may as well not exist. A hook that catches a committed binding.pry in 200

Remote pairing has a bad reputation earned mostly by bad sessions: three hours on a call, one person driving the whole time, the other watching a laggy screen share and drifting into Slack.

Controller specs let you call an action directly and assert on assigned instance variables. They’re fast, they’re focused, and the Rails team has been steering people away from them for years. The reason

You want to add display logic to a model without putting it on the model. So you reach for SimpleDelegator, wrap the object, add three methods, and it works — until something calls

Invalid configuration. That’s the whole message. Somewhere in a 300-line YAML file there’s a problem, and the program knows exactly which key, which line, and what it expected — it just chose not

rails db:migrate on a forty-row development database takes eleven milliseconds. The same migration against a forty-million-row production table takes an ACCESS EXCLUSIVE lock, queues every query behind it, exhausts the connection pool, and