The general approach that I take, is that an error message is one of the most stressful occurrences that a user encounters, so it's incumbent upon me to make it as pain-free as possible.
First of all, unless I'm writing an engineering tool, my users aren't geeks, and don't especially care why the error is happening (geeks always need to know why). They just need to know that what was expected, did not happen. If there is a remedy, and it can be simply stated, then I can add that, but it needs to be short and simple. Longer stuff needs to go into some kind of secondary screen (which probably won't be read).
Also, I take the "shopkeeper" approach. The customer is always right, and it's never the customer's fault. I avoid any hints of blaming the user (even if it is their fault), and try to be polite and helpful[0].
Of course, the best way to deal with errors, is to avoid them. I try to design good affordances.
The rules are different for SDKs, though. In that case, I tend to send a great deal of information back. I take advantage of Swift's enums, and the ability to associate data. It can allow me to nest error reports.
First of all, unless I'm writing an engineering tool, my users aren't geeks, and don't especially care why the error is happening (geeks always need to know why). They just need to know that what was expected, did not happen. If there is a remedy, and it can be simply stated, then I can add that, but it needs to be short and simple. Longer stuff needs to go into some kind of secondary screen (which probably won't be read).
Also, I take the "shopkeeper" approach. The customer is always right, and it's never the customer's fault. I avoid any hints of blaming the user (even if it is their fault), and try to be polite and helpful[0].
Of course, the best way to deal with errors, is to avoid them. I try to design good affordances.
The rules are different for SDKs, though. In that case, I tend to send a great deal of information back. I take advantage of Swift's enums, and the ability to associate data. It can allow me to nest error reports.
[0] https://littlegreenviper.com/miscellany/the-road-most-travel...