Possible bug with adding subviews?

[Stephen Brandon]

Hi,

I converted a MacOSX nib using nib2gmodel, and am debugging the results :=(

The issue here is that GNUstep complains thus:

Uncaught exception NSInvalidArgumentException, reason: addSubview: creates a 
loop in the views tree!

The problem occurs under the following conditions:

- unarchiving from gmodel file
- NSBox object ("box") has contentview "a"
- nsview "a" also appears in box's subviews array
- nsview "a" has superview "box"
- during the unarchiving of "a" (superview "box" is decoded, then [superview 
addSubview:self] is called)

The exception is thrown in -[NSView addSubview:], where the box's 
_content_view object is asked to add *itself*, since _content_view == "a":

if ([self isDescendantOf: aView]) {...   (throws exception)


I'm not sure where the best place to fix this is. Should the unarchiver do a 
check to see if the superview's contentview equals itself? (but then the 
superview would never add the view to its subview list). Or should NSView 
just do a check to see if a view is adding itself as a subview, and silently 
ignore it?

It's also possible that the situation as described above should never 
actually happen, and that either my original nib is in a mess, or nib2gmodel 
made an error in converting it.

Any help welcome!

Cheers,
Stephen Brandon