Fix use-after-release mistake in currtid() and currtid2() for views

This issue has been present since the introduction of this code as of
a3519a2 from 2002, and has been found by buildfarm member prion that
uses RELCACHE_FORCE_RELEASE via the tests introduced recently in
e786be5.

Discussion: https://postgr.es/m/20200601022055.GB4121@paquier.xyz
Backpatch-through: 9.5

diff --git a/src/backend/utils/adt/tid.c b/src/backend/utils/adt/tid.c
index cc699ee2f422d495fe789bf7a61774dc99c4c953..509a0fdffcd6b8528f803cdbe7eca1c90fc6cda8 100644 (file)
--- a/src/backend/utils/adt/tid.c
+++ b/src/backend/utils/adt/tid.c
@@ -338,8 +338,13 @@ currtid_for_view(Relation viewrel, ItemPointer tid)
                                        rte = rt_fetch(var->varno, query->rtable);
                                        if (rte)
                                        {
+                                               Datum           result;
+
+                                               result = DirectFunctionCall2(currtid_byreloid,
+                                                                                                        ObjectIdGetDatum(rte->relid),
+                                                                                                        PointerGetDatum(tid));
                                                table_close(viewrel, AccessShareLock);
-                                               return DirectFunctionCall2(currtid_byreloid, ObjectIdGetDatum(rte->relid), PointerGetDatum(tid));
+                                               return result;
                                        }
                                }
                        }