BUG #16214: Settings is not copy

The following bug has been logged on the website:

Bug reference: 16214
Logged by: Michail Shurutov
Email address: shurutov(at)gmail(dot)com
PostgreSQL version: 11.6
Operating system: Gentoo, RHEL
Description:

I downloaded and ulpoaded into local PostgreSQL instance demo database from
Postgres Professional: https://postgrespro.ru/education/demodb
Than I made copy as "CREATE DATABASE demo_small template demo", after this I
noticed:
postgres=# \c demo

You are now connected to database "demo" as user "postgres".

demo=# select name,setting from pg_settings where name = 'search_path';

name | setting

-------------+------------------

search_path | bookings, public

(1 row)



demo=# \c demo_small

You are now connected to database "demo_small" as user "postgres".

demo_small=# select name,setting from pg_settings where name =
'search_path';
name | setting

-------------+-----------------

search_path | "$user", public

(1 row)



demo_small=# \q

Parameter "search_path" was not copied.

And command "ALTER DATABASE" was not in included into dump made by
pg_dump:
mshurutov(at)desktop fromarch $ sudo -u postgres pg_dump -C demo_small >
/var/tmp/demo_small.sql
mshurutov(at)desktop fromarch $ grep "ALTER DATABASE" demo-small-20170815.sql
ALTER DATABASE demo SET search_path = bookings, public;
ALTER DATABASE demo SET bookings.lang = ru;
mshurutov(at)desktop fromarch $ grep "ALTER DATABASE" /var/tmp/demo_small.sql

ALTER DATABASE demo_small OWNER TO postgres;
mshurutov(at)desktop fromarch $