WITH db_privs AS (SELECT datname, unnest(datacl)::text AS priv  
FROM pg_database
WHERE datname=current_database()),
db_extracted_privs AS (SELECT 
left(priv, (position('=' IN priv)-1)) AS grantee,
substring(priv, position('=' IN priv)+1, position('/' IN priv)-position('=' IN priv)-1) AS privileges
FROM db_privs),
grantees AS (SELECT table_privileges.grantee
FROM information_schema.table_privileges
WHERE table_schema NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL)
UNION SELECT routine_privileges.grantee
FROM information_schema.routine_privileges
WHERE routine_schema NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL))
SELECT format('GRANT CONNECT ON DATABASE %1$I TO %2$I;', current_database(), grantee) AS statements
FROM grantees
WHERE NOT EXISTS (SELECT *
FROM db_extracted_privs AS dep
WHERE dep.grantee=grantees.grantee
AND privileges~'c')
AND grantee<>'PUBLIC'
AND NOT EXISTS (SELECT usename
FROM pg_user
WHERE pg_user.usename=grantees.grantee
AND usesuper=TRUE)
ORDER BY grantee;