Xcode 7.2：NSHTMLTextDocumentAttribute的未定义符号

Question

Updated to Xcode 7.2 and I can no longer compile. I'm getting a few Undefined Symbols errors:

undef: _OBJC_CLASS_$_NSTextContainer
undef: _OBJC_CLASS_$_NSMutableParagraphStyle
undef: _OBJC_CLASS_$_NSLayoutManager
undef: _NSUnderlineStyleAttributeName
undef: _NSParagraphStyleAttributeName
undef: _NSLinkAttributeName
undef: _OBJC_CLASS_$_NSTextStorage
undef: _OBJC_CLASS_$_NSTextAttachment
undef: _NSBaselineOffsetAttributeName
undef: _NSBackgroundColorAttributeName
undef: _NSDocumentTypeDocumentAttribute
undef: _NSFontAttributeName
undef: _NSHTMLTextDocumentType
undef: _NSForegroundColorAttributeName
undef: _OBJC_CLASS_$_UIFont

All of the classes seem to have to do with UIKit... but I checked and it's being imported.

The offending code does not throw errors until linking.

Anybody know what's going on?

Note: I have cleaned, deleted derived data, etc.

Answer 1

Deleting and Reinstalling Xcode 7.2 worked for a while, but the issue kept returning.

I finally narrowed down the issue to a new module I had added to one of my branches. I had created a new module I called UIFoundation . I was pushing common components into that module (shared across multiple projects). Since we have Foundation and UIKit framework from Apple, I figured UIFoundation would be safe. I was wrong. Apple must use this name internally because simply adding a module with that name to the project caused it to fail when linking. Renaming the module to something else fixed the problem completely.

But the issue would persist itself on other branches once I had built on the branch that had the UIFoundation module. Even deleting Derived Data wouldn't fix the issue. I can only assume there was some cache or some setting that was being affected, which semi-permanently confused Xcode?... not sure. Whatever the case is, creating deleting UIFoundation and replacing it with another module name worked.