Capybara Webkit runtime warning: Class is implemented in both

Question

I get a slew of warnings from webkit when I run rspec. I am using capybara-webkit and qt installed from brew. I sure would love to fix these. Thanks for your help.

Warnings like: "Implemented in both"

objc[97388]: Class WebCoreMovieObserver is implemented in both /usr/local/Cellar/qt/4.8.0/lib/QtWebKit.framework/Versions/4/QtWebKit and /System/Library/Frameworks/WebKit.framework/Versions/A/Frameworks/WebCore.framework/Versions/A/WebCore. One of the two will be used. Which one is undefined.
objc[97388]: Class WebCoreSharedBufferData is implemented in both /usr/local/Cellar/qt/4.8.0/lib/QtWebKit.framework/Versions/4/QtWebKit and /System/Library/Frameworks/WebKit.framework/Versions/A/Frameworks/WebCore.framework/Versions/A/WebCore. One of the two will be used. Which one is undefined.
objc[97388]: Class WebVideoFullscreenWindow is implemented in both /usr/local/Cellar/qt/4.8.0/lib/QtWebKit.framework/Versions/4/QtWebKit and /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit. One of the two will be used. Which one is undefined.
objc[97388]: Class WebVideoFullscreenController is implemented in both /usr/local/Cellar/qt/4.8.0/lib/QtWebKit.framework/Versions/4/QtWebKit and /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit. One of the two will be used. Which one is undefined.
objc[97388]: Class WebVideoFullscreenHUDWindowController is implemented in both /usr/local/Cellar/qt/4.8.0/lib/QtWebKit.framework/Versions/4/QtWebKit and /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit. One of the two will be used. Which one is undefined.
objc[97388]: Class WebVideoFullscreenHUDWindow is implemented in both /usr/local/Cellar/qt/4.8.0/lib/QtWebKit.framework/Versions/4/QtWebKit and /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit. One of the two will be used. Which one is undefined.
objc[97388]: Class WebWindowFadeAnimation is implemented in both /usr/local/Cellar/qt/4.8.0/lib/QtWebKit.framework/Versions/4/QtWebKit and /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit. One of the two will be used. Which one is undefined.
objc[97388]: Class WebWindowScaleAnimation is implemented in both /usr/local/Cellar/qt/4.8.0/lib/QtWebKit.framework/Versions/4/QtWebKit and /System/Library/Frameworks/WebKit.framework/Versions/A/WebKit. One of the two will be used. Which one is undefined.

EDIT: I'm only interested in answers that involve qt installed from brew. Thanks.

Answer 1

I recommend to download and use the pre-built version of Qt library.

I was trying to build using MacPorts and had difficulty. Qt site have prebuilt binary for that. In my case, it's working fine.

I've been using capybara-webkit with pre-built Qt for nearly a year, without issues on MacOS X 10.6 and 10.7