[mikewest]

WebKit and Chromium are different repositories, and point to each other via a "DEPS" (dependencies) file. We roll new revisions of WebKit into Chromium regularly, and call the process of diagnosing and fixing problems with the rolls "Gardening": http://www.chromium.org/developers/how-tos/webkit-gardening is a good reference.

[tripzilch]

Hey, clicking around that Wiki it has some pretty interesting information. Do other large open-source projects have a very similar workflow?

[zanny]

You mean having full-time engineers handling merge conflicts / upstream breakage / regressions / running test suites? In anything sufficiently large, that becomes a major issue inevitably.

Almost any project worth its salt has someone doing testing. But it is really time consuming.

[bradleyjg]

The most significant long term upstream-downstream relationships are probably the linux distros to the kernel.