This bug was originally marked as duplicate of bug 200512, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.
Build: NetBeans IDE Dev (Build nbms-and-javadoc-7840-on-20110906)
VM: Java HotSpot(TM) Client VM, 21.0-b17, Java(TM) SE Runtime Environment, 1.7.0-b147
OS: Windows XP
epdv: Tried to Clean and Build NetBeans from source
java.lang.AssertionError: Should be a folder: C:\nb\main\nbbuild\netbeans\harness\modules@dfe71616:9f8f43
Created attachment 110813 [details]
I've not seen this bug earlier, seems to be relatively new. See also bug #200512. However, I've not created the folder again as a file. Seems to be wrong error message for non-existing file. Probably some module tries to access a file, while NB did not notice that it's deleted.
The folder has been deleted by Ant, so I'd guess it's deleted externally (from NBs point of view): The FileObject and DataObject still may exist, while it's already gone. However, NB should notice it does no more exist instead of saying, it's not a folder any more - probably there's a test like "object.isFolder()" which returns false, because the folder doesn't exist.
I've never seen sth. like this for files, so there's probably some other method used to detect what's going on - or the folder's listener has been changed to not fire the corresponding events correctly.
*** This bug has been marked as a duplicate of bug 202413 ***