A quiet week, and the bug that ate a job

Six commits this week, and nothing reached production. I am writing the post anyway. A weekly blog that only appears in the weeks with something impressive to announce is not a record of how software gets made, and the quiet weeks are where most of the real defects get found.

One of the six was worth the whole week.

A role that disappeared

The resume generator takes your profile — the full work history, everything you have ever done — and produces a document for one specific job. Internally it has to keep track of which role each generated bullet belongs to, so it builds a key for every role out of a few fields joined together with a delimiter.

The delimiter was a character that could also show up inside the data. When a role contained it, the key no longer matched anything, and that role could quietly fail to reach the generated resume. No error. No warning. A resume that comes back looking perfectly normal, with two years of somebody’s working life missing from the middle of it.

The worst bugs in a tool like this are not the ones that crash. They are the ones that produce a plausible, complete-looking document that is wrong.

That is exactly the failure mode I am most afraid of here, because a person cannot catch it by looking. If the app throws an error, you know. If your resume comes back and the 2019 to 2021 role is gone, you might not notice until the interview where somebody asks what you were doing that year.

The fix has two parts. The key now uses a printable delimiter that cannot collide with the contents. And separately, the generator now guarantees that every role in the profile reaches the output — that is a property that gets checked, not a consequence of the keying working correctly. Those are two different repairs and I wanted both. The first fixes this bug. The second makes the whole class of bug visible if it ever comes back in another form.

The typing bug

The other one to mention is small and purely about respect for the person using the thing. Several fields in the profile take a list — skills, tools, keywords — separated by commas. The input was processing the separator as you typed, which meant that trying to type a list naturally fought you the whole way. It is the sort of bug that makes someone conclude the product is cheap, and they are not wrong to conclude that.

Why the week was quiet

No mystery: the job-feed backend is in the middle of being built, and it is not the kind of work that produces anything worth releasing halfway. The honest summary of the week is four bug fixes, one of them serious, and a lot of unfinished plumbing I will describe when it works.