>> Hm, buildfarm's not complaining --- what's the test case?
> This was discovered while testing/reviewing the latest version of the > INCLUDE covering indexes patch. It now seems to be unrelated.
Oh, wait ... I wonder if you saw that because you were running a new backend without having re-initdb'd? Once you had re-initdb'd, then of course there would be no old-format btree indexes anywhere. But if you hadn't, then anyplace that was not prepared to cope with the old header format would complain about pre-existing indexes.
In short, this sounds like a place that did not get the memo about how to cope with un-upgraded indexes.
That's an issue, because meta-page should be upgraded "on the fly".
That was tested, but perhaps without assertions. I'll investigate more on
