I keep hitting the following assertion in UStringImpl::create(), which was introduced in r54545: ASSERT(vector.data()); This function is sometimes legitimately called with an empty vector. It behaves correctly when called with an empty vector, because it special-cases for a vector.size() result of 0 and returns &empty() in that case.
The assertion is in UStringImpl::adopt(), not UStringImpl::create(). I'll have a patch in a moment.
Created attachment 48435 [details] Patch to only assert that vector.data() is non-empty if vector.size() is non-zero.
Comment on attachment 48435 [details] Patch to only assert that vector.data() is non-empty if vector.size() is non-zero. ok
CC'ing Gavin, since he introduced the ASSERT.
Fixed in http://trac.webkit.org/changeset/54563