It looks like this is -- like a lot of plpgsql patches -- having
difficulty catching the attention of reviewers and committers.
Aleksander asked for a test and Pavel put quite a bit of work into
adding a good test case. I actually like that there's a test because
it shows the API can be used effectively.
From my quick skim of this code it does indeed look like it's ready to
commit. It's mostly pretty mechanical code to expose a couple fields
so that a debugger can see them.
Pavel, are you planning to add a debugger to contrib using this? The
test example code looks like it would already be kind of useful even
in this form.