runtime error copying oids field

In our testPgRegressTrigger test log, I saw the following (this was for a relatively old version of PG):

197859  [ts-1]  ../../../../../../src/postgres/src/backend/commands/indexcmds.c:1062:22: runtime error: null pointer passed as argument 2, which is declared to never be null
197860  [ts-1]  /opt/yb-build/brew/linuxbrew-20181203T161736v9/include/string.h:43:28: note: nonnull attribute specified here
197861  [ts-1]       #0 0xacbd0f in DefineIndex $YB_SRC_ROOT/src/postgres/src/backend/commands/../../../../../../src/postgres/src/backend/commands/indexcmds.c:1062:4
197862  [ts-1]       #1 0x11441e0 in ProcessUtilitySlow $YB_SRC_ROOT/src/postgres/src/backend/tcop/../../../../../../src/postgres/src/backend/tcop/utility.c:1436:7
197863  [ts-1]       #2 0x114141f in standard_ProcessUtility $YB_SRC_ROOT/src/postgres/src/backend/tcop/../../../../../../src/postgres/src/backend/tcop/utility.c:962:4
197864  [ts-1]       #3 0x1140b65 in YBProcessUtilityDefaultHook $YB_SRC_ROOT/src/postgres/src/backend/tcop/../../../../../../src/postgres/src/backend/tcop/utility.c:3574:3
197865  [ts-1]       #4 0x7f47d4950eac in pgss_ProcessUtility $YB_SRC_ROOT/src/postgres/contrib/pg_stat_statements/../../../../../src/postgres/contrib/pg_stat_statements/pg_stat_statements.c:1120:4

This was the line runtime error was raised:

        memcpy(part_oids, partdesc->oids, sizeof(Oid) * nparts);

	if (nparts > 0)	{		PartitionBoundInfo boundinfo;		int		   *mapping;		int			next_index = 0;
		result->oids = (Oid *) palloc0(nparts * sizeof(Oid));