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.

Stowell

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

Fluctuate

I thought brew used a pre-built qt. How is brew's qt different from your qt? Please note that I am not using MacPorts. – Stowell

I'm not using brew so I may misunderstand how brew configuration work, but according to github.com/mxcl/homebrew/blob/master/Library/Formula/qt.rb It's configuring and making it. – Fluctuate

Doesn't explain why the error occurs, but I suspect that it does indeed get rid of the warnings so awarding the bounty. – Bab

Answer 2

Apologies... this belongs as a comment on @shigeya's answer.

The pre-built Qt binary does not fix this problem. Installed 4.8.2 just now, along with brew remove --force qt, resulting in:

objc[67716]: Class WebCoreMovieObserver is implemented in both /Library/Frameworks/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[67716]: Class WebCoreSharedBufferData is implemented in both /Library/Frameworks/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[67716]: Class WebVideoFullscreenWindow is implemented in both /Library/Frameworks/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[67716]: Class WebVideoFullscreenController is implemented in both /Library/Frameworks/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[67716]: Class WebVideoFullscreenHUDWindowController is implemented in both /Library/Frameworks/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[67716]: Class WebVideoFullscreenHUDWindow is implemented in both /Library/Frameworks/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[67716]: Class WebWindowFadeAnimation is implemented in both /Library/Frameworks/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[67716]: Class WebWindowScaleAnimation is implemented in both /Library/Frameworks/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.

Monotony

Also, while this does not answer the question, I found that switching from capybara-webkit to poltergeist (based on brew installed phantomjs which uses webkit) made the warnings go away. – Monotony