In your case, they should've certainly dug into your open source, at least if it was directly in their line of business.
I certainly love it when I ask a candidate "tell me about a project you found interesting" and they can go into details, talk about tradeoffs, etc. Sadly, most candidates can't. They can't come up with anything better than "well I rewrote the thing, and it was challenging since I hadn't used Kotlin before, learning Kotlin was interesting." So at that point I'm unimpressed, but I'll give them a chance to code still because (a) not everybody has had opportunities to work on interesting stuff and (b) I wouldn't have enough people to hire otherwise.
But if "has open source software we use" is the bar, you're gonna fail a lot more good engineers than you would using algo questions.
In your case, they should've certainly dug into your open source, at least if it was directly in their line of business.
I certainly love it when I ask a candidate "tell me about a project you found interesting" and they can go into details, talk about tradeoffs, etc. Sadly, most candidates can't. They can't come up with anything better than "well I rewrote the thing, and it was challenging since I hadn't used Kotlin before, learning Kotlin was interesting." So at that point I'm unimpressed, but I'll give them a chance to code still because (a) not everybody has had opportunities to work on interesting stuff and (b) I wouldn't have enough people to hire otherwise.
But if "has open source software we use" is the bar, you're gonna fail a lot more good engineers than you would using algo questions.