Mark pg_config() stable rather than immutable

jconway · jconway · commit 290e3b77fde9 · 2019-02-17T09:21:13.000-05:00
pg_config() has been marked immutable since its inception. As part of a larger discussion around the definition of immutable versus stable and related implications for marking functions parallel safe raised by Andres, the consensus was clearly that pg_config() is stable, since it could possibly change output even for the same minor version with a recompile or installation of a new binary. So mark it stable. Theoretically this could/should be backpatched, but it was deemed to be not worth the effort since in practice this is very unlikely to cause problems in the real world. Discussion: https://postgr.es/m/20181126234521.rh3grz7aavx2ubjv@alap3.anarazel.de
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
@@ -10433,7 +10433,7 @@
 
 # pg_config
 { oid => '3400', descr => 'pg_config binary as a function',
-  proname => 'pg_config', prorows => '23', proretset => 't', proparallel => 'r',
+  proname => 'pg_config', provolatile => 's', prorows => '23', proretset => 't', proparallel => 'r',
   prorettype => 'record', proargtypes => '', proallargtypes => '{text,text}',
   proargmodes => '{o,o}', proargnames => '{name,setting}',
   prosrc => 'pg_config' },
