Comment by wolrah
1 hour ago
> I'm not sure how I'd do acceptance/E2E testing without the magic of port 0.
Same as anything else, an explicit flag to achieve the same "just give me a port" functionality as this "magic number" does without resulting in the documented unpredictable behavior around a technically legitimate port number.
As the article points out, most if not all of the services exposed on port 0 seem to be accidental and likely resulted from people assuming this magic behavior applies everywhere instead of just to one specific API.
> Same as anything else
Yeah, obviously I'm a programmer so I'm well aware it's technically possible, it was a bit of an exaggeration to explain how much value I feel I get from it.
> most if not all of the services exposed on port 0 seem to be accidental
No program actually end up "exposed on port 0", if it's not supported it won't be able to create a listener on that port, AFAIK. Most yeah, all no. P2P software commonly leverage port 0, and other "discover<>connect" types of software. But I'd agree that it's most likely accidental if outside of those niches.