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The following bug has been logged on the website:

Bug reference:      15669
Logged by:          Thibaut MADELAINE
Email address:      thibaut.madelaine@dalibo.com
PostgreSQL version: 11.2
Operating system:   Debian
Description:        

Hello,

A client found a possible bug in version 11.2.

Trying to use "unnest" on an array record with the predicate "false" fails
with the message:
ERROR:  set-valued function called in context that cannot accept a set

In PostgreSQL 10.7 and before, it is possible to run the following query:
==========
thibaut=# select version();
                                                      version               
                                      
-------------------------------------------------------------------------------------------------------------------
 PostgreSQL 10.7 (Debian 10.7-1.pgdg100+1) on x86_64-pc-linux-gnu, compiled
by gcc (Debian 8.2.0-16) 8.2.0, 64-bit
(1 ligne)

thibaut=# WITH test AS ( SELECT array[1,2] AS intarr ) 
                 SELECT unnest(intarr) AS lot_id FROM test WHERE false;
 lot_id 
--------
(0 ligne)
==========

In version 11.2, the same query fails:
==========
thibaut=# select version();
                                                      version               
                                      
-------------------------------------------------------------------------------------------------------------------
 PostgreSQL 11.2 (Debian 11.2-1.pgdg100+1) on x86_64-pc-linux-gnu, compiled
by gcc (Debian 8.2.0-16) 8.2.0, 64-bit
(1 ligne)

thibaut=#  \set VERBOSITY verbose
thibaut=# WITH test AS ( SELECT array[1,2] AS intarr ) 
                 SELECT unnest(intarr) AS lot_id FROM test WHERE false;
ERROR:  0A000: set-valued function called in context that cannot accept a
set
LIGNE 2 :  SELECT unnest(intarr) as lot_id FROM test where false;
                  ^
EMPLACEMENT : ExecInitFunc, execExpr.c : 2212
==========

The same query with a false predicate that needs to be evaluated succeeds:
==========
thibaut=# with test as ( SELECT array[1,2] as intarr )
 SELECT unnest(intarr) as lot_id FROM test where now()<'1996-01-01';
 lot_id 
--------
(0 ligne)
==========