Ruby on @zhisme :: signal over noise

The Constant Frozen at Boot Bug: A Ruby Exercise For An Interview

Wed, 10 Jun 2026 00:00:00 +0000

I like interview questions that come from real incidents instead of a puzzle book. You can’t google your way out of them, and the candidate’s reasoning maps directly onto the job. This one came from a payment service. It looks trivial. It is not.

I’ve stripped the production code and rebuilt the same shape around a fake payment router. The bug is identical; the names are not.

The Question

Here is a class that routes payments to a gateway. Occasionally a charge is
written to the database with method_id = NULL, even though the payment method
clearly exists in the payment_methods table. No exception is raised. The only
thing that reliably fixes it is restarting the process. Find the bug.

Ruby IO buffering

Fri, 16 Jan 2026 00:00:00 +0000

Your Kibana/Cloudwatch/Grafana have different timestamps, you don’t see recent logs from your application. Why is that? You may ask. Some QA reports that your application is not working/was not deployed, asking you to review the deploy process. Or even worse: asking your devops colleagues to “something went wrong” with last deployment could you check?

You login into your shell running kubectl get pods to verify timestamps update or checking Helm releases helm ls. But everything seems fine, everything deployed. CI/CD is green, all timestamps updated. But yet. QA does not see the logs. Where have they gone?

You Don’t Need Types in Ruby

Wed, 29 Oct 2025 00:00:00 +0000

There was a lively discussion on Hacker News here about Sorbet and static typing in Ruby that inspired this post.

It’s fascinating how people try to make Ruby look like a statically typed language. But this isn’t the first attempt — and every time, it ends up fighting against what Ruby fundamentally is.

Turning Ruby into Java isn’t progress. It’s a step backward.
Let me explain why.

How Ruby Deals with Types

Ruby is a dynamically typed, object-oriented language designed around message passing — an idea borrowed from Smalltalk.

lazy_names gem, how much time do you spend in console?

Sun, 12 Jan 2020 00:00:00 +0000

I’m happy to share the lazy_names gem!
This gem allows you to define a config file that maps long, namespaced constants to something simpler and more intuitive:

'Models::Users::CreditCard': 'UserCard'

I spend a lot of time in the console, which is why I originally wrote this gem. Here’s a quick look at my most frequently run commands from my Zsh history:

$: history | awk '{$1=""; print $0}' | sort | uniq -c | sort -nr
 647 gs
 135 rc # rails console
 135 ls
 134 gd
 ...

Do you use the Ruby console much while developing? I personally like to check my code directly in the console — calling methods to inspect return values — especially in the early development stage before tests are written. Sometimes, I need to drop records from the database or build some structs on the fly.