Comment 6 for bug 1595781

I'm still not happy with the general idea. lxml makes a couple of assumptions about the tree, which may no longer hold for externally provided trees. That suggests that lxml would at least want to make a copy instead of using the tree as it comes in.

Is it really that bad to serialise the tree after building it and to parse it with lxml then? How performance critical can such code be?

What kind of "custom parser" do you actually use? Is that really external to libxml2?