Here is v3 version of the patch. I've fixed some comments and added some words to docs.
Hi again Andrey,
Cfbot reported the following difference (twice) in the index_including_gist test:
- ERROR: included columns must not intersect with key columns + ERROR: relation "tbl_gist_idx" already exists
Well, both of those errors are valid complaints in this case... maybe the order of checks changed in master since you wrote the patch? Probably better to use a different name for the index anyway.
Thanks! The problem appeared with commit 701fd0b [0] which dropped validation rules checked in failed test. Here's the patch with fixed tests.