My local tests started failing soon after upgrading my machine to Safari 4.0.4. Some research and pointers from the GWT folk pointed me at the root cause, a WebKit bug which is now fixed.
Kelly Norton pointed me at a quick fix:
- Download the latest WebKit nightly from here
- Save it locally
- Add the following environment variable to your testing .launch targets (using the path to your new WebKit.app, of course). Tests run from Ant or the command line will need to use the appropriate tasks or shell commands:
Name: DYLD_FRAMEWORK_PATH Value: /Applications/path-to-your-local-webkit/WebKit.app/Contents/Frameworks/10.5
- Snow Leopard users will need to use 10.6 in the path above.
The proper fix should arrive in WebKit 4.0.5 at some point, but this will keep you running for now.
Jim Douglas has posted more detailed instructions on how to configure your launch targets on the GWT issue here: Issue #4220: GWT crash (Safari 4.0.4)

Thanks, Matt! I linked to this blog entry from http://code.google.com/p/google-web-toolkit/issues/detail?id=4220#c22, with instructions for getting it working in Eclipse.
Jim,
Thanks for fleshing out the instructions some more! I’ll link this entry to that issue as well.
Thank you for this fix. Saved quite a few of my hair.
Brice.
Thanks, you just saved my ass today…
This fix works for me as well. Many thanks .. saved me a lot of trouble and time