presentError:

FROM : Quincey Morris
DATE : Sat Apr 19 21:47:51 2008

(1) The HIG guidelines say, regarding alert icons:

> "In rare cases, you may want to display a caution icon in your 
> alert, badged with the application icon as shown in Figure 14-48. A 
> badged alert is appropriate only if the user is performing a task, 
> such as installing software, and a possible side effect of that task 
> would be the inadvertent destruction of data. Don’t use a caution 
> icon for tasks whose only purpose is to overwrite or remove data, 
> such as Save or Empty Trash; too-frequent use of the caution icon 
> dilutes its significance."


Yet presentError: *always* chooses to use a badged caution icon, 
AFAICT, even though there's no good reason to assume that an error in 
general implies the possible "inadvertent destruction of data". For 
example, NSDocumentController reports (via presentError:, I assume) a 
failure to create or open a document with a caution icon, and in 
neither case is it likely that data destruction is imminent.

(2) According to the NSResponder class reference for the alert 
resulting from 'presentError:',

> "The alert displays information found in the NSError object anError; 
> this information can include error description, recovery suggestion, 
> failure reason, and button titles (all localized)."



In fact, AFAICT the failure reason is never included in the alert -- 
the secondary (smaller) text always comes from the recovery suggestion 
and the failure reason is ignored.

(3) According to the NSResponder class reference, a responder passes 
presentError to the next error responder and:

> "if there is no next responder, it passes the error object to NSApp, 
> which displays a document-modal error alert"



I had hoped this meant that NSApp cleverly displayed the error as a 
sheet on the document window and waited for it to be dismissed. In 
fact, if you send presentError: to a NSDocument you get an application-
modal alert.

Before I radar these as bugs, I though I'd see if anyone has any 
comments. Maybe I misunderstand something.