From 17082a88eadfca79b50c04c5a78a2c38ee4f5d9c Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Tue, 13 Jun 2017 08:49:41 -0400 Subject: [PATCH] Prevent copying default collation This will not have the desired effect and might lead to crashes when the copied collation is used. Reported-by: Tom Lane --- src/backend/commands/collationcmds.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/backend/commands/collationcmds.c b/src/backend/commands/collationcmds.c index ab702c2479c..91b65b174d3 100644 --- a/src/backend/commands/collationcmds.c +++ b/src/backend/commands/collationcmds.c @@ -120,6 +120,18 @@ DefineCollation(ParseState *pstate, List *names, List *parameters, bool if_not_e collprovider = ((Form_pg_collation) GETSTRUCT(tp))->collprovider; ReleaseSysCache(tp); + + /* + * Copying the "default" collation is not allowed because most code + * checks for DEFAULT_COLLATION_OID instead of COLLPROVIDER_DEFAULT, + * and so having a second collation with COLLPROVIDER_DEFAULT would + * not work and potentially confuse or crash some code. This could be + * fixed with some legwork. + */ + if (collprovider == COLLPROVIDER_DEFAULT) + ereport(ERROR, + (errcode(ERRCODE_INVALID_OBJECT_DEFINITION), + errmsg("collation \"default\" cannot be copied"))); } if (localeEl) -- 2.30.2