so 19. 12. 2020 v 21:35 odesílatel Tom Lane <tgl@sss.pgh.pa.us> napsal:
I wrote: > However, further experimentation found a case that fails: > regression=# select '3'::jsonb || '{}'::jsonb; > ERROR: invalid concatenation of jsonb objects > I wonder what is the point of this weird exception, and whether > whoever devised it can provide a concise explanation of what > they think the full behavior of "jsonb || jsonb" is. Why isn't > '[3, {}]' a reasonable result here, if the cases above are OK?
Here is a proposed patch for that. It turns out that the third else-branch in IteratorConcat() already does the right thing, if we just remove its restrictive else-condition and let it handle everything except the two-objects and two-arrays cases. But it seemed to me that trying to handle both the object || array and array || object cases in that one else-branch was poorly thought out: only one line of code can actually be shared, and it took several extra lines of infrastructure to support the sharing. So I split those cases into separate else-branches.
This also addresses the inadequate documentation that was the original complaint.
Thoughts? Should we back-patch this? The existing behavior seems to me to be inconsistent enough to be arguably a bug, but we've not had field complaints saying "this should work".
