A place for code I want to explain, mistakes worth remembering, and the occasional story from my life.
PHP 2 min read
A CSV contains the date 2026-02-31. A date parser may normalize it into March instead of treating it as an invalid business date. For an expiry date or reporting period, that silen...
PHP 2 min read
You filter an imported list before saving it, then discover that out-of-stock products disappeared. The default array_filter behavior removes values considered empty, including zer...
PHP 2 min read
A permission list contains integer identifiers, while a request supplies strings. If membership testing quietly converts types, a value can match even though it violates the input...
PHP 2 min read
A webhook signature check fails even though the decoded payload looks correct. One common cause is decoding JSON and encoding it again before verification. Whitespace and key order...
PHP 2 min read
An importer reads a large file, converts every record into an array, then loops over that array to save it. The temporary copy can become larger than the original file. A generator...
PHP 2 min read
A product name contains a comma: "Washer, stainless". Splitting each line with explode creates an extra column and can shift the stock count into the wrong field. CSV needs a CSV p...
PHP 2 min read
A successful HTTP request does not guarantee a usable JSON document. A proxy can return HTML, a supplier can truncate a response, and the literal JSON value null can be perfectly v...
PHP 2 min read
An inventory API sends {"stock":0}. That is a valid stock count. Another response omits stock because the supplier did not include that field. Treating both responses as "empty" ma...
MySQL 2 min read
A provider sends the same event twice. Two workers both check whether the event exists, both see nothing, and both process it. The initial SELECT is not a concurrency guarantee. En...
