Debugging

Recovering Work After a Bad git reset --hard

Your commits are almost certainly still there. Here is how reflog works, what it cannot save, and the recovery path for each case.

Kubernetes

CrashLoopBackOff: A Complete Diagnostic Flowchart

CrashLoopBackOff is not an error, it is a symptom with about nine distinct causes. Here is how to identify which one you have in under three minutes.

Networking

redirect_uri_mismatch and the Rest of OAuth Debugging

OAuth errors are unhelpful by design, because detailed errors would help attackers too. Here is how to work out what is actually wrong.

AI

Testing an LLM Feature When the Output Is Different Every Time

You cannot assert equality on a model response. You can assert a lot of other things, and most teams assert none of them.

Debugging

How Breakpoints Actually Work: INT3 and ptrace

Setting a breakpoint rewrites your program's machine code while it runs. Here is the mechanism, from the 0xCC byte up to why conditional breakpoints are slow.

React

Hydration Failed: Every Cause of the Initial UI Mismatch

A complete diagnostic guide to React hydration mismatches: the eight real causes ranked by how often they actually happen, with the fix for each.

PostgreSQL

The Database Migration That Locked the Table for Nine Minutes

Adding a column should be instant. Sometimes it is not, and the difference is worth knowing before you run it in production.

Debugging

What Running Hosting Infrastructure Taught Me About Debugging

Five years of keeping other people's websites online rewired how I think about failure. Mostly by making the consequences immediate.

Python

How to Read a Python Traceback (Most Read It Backwards)

The last line tells you what broke. The middle tells you why. Here is how to get a working hypothesis out of a traceback in about ten seconds.

Shopify

Shopify Metafields: Why Your Value Renders as Escaped JSON

You added a metafield, output it in Liquid, and got a wall of quotes and brackets. Here is what metafield_tag does and when you still need the raw value.

AI

Why Your Coding Agent Got Worse Halfway Through the Session

It was sharp for an hour and now it is contradicting itself and reintroducing bugs you already fixed. That is context degradation, and it is manageable.

Debugging

Every Bug Is a Story About a Wrong Assumption

Why I started a blog about software failure instead of software success, and what a debugging writeup should actually contain.