Fix pg_dump to assign domain array type OIDs during pg_upgrade.

During a binary upgrade, all type OIDs are supposed to be assigned by
pg_dump based on their values in the old cluster.  But now that domains
have arrays, there's nothing to base the arrays' type OIDs on, if we're
upgrading from a pre-v11 cluster.  Make pg_dump search for an unused type
OID to use for this purpose.  Per buildfarm.

Discussion: https://postgr.es/m/E1dyLlE-0002gT-H5@gemulon.postgresql.org

src/bin/pg_dump/pg_dump.c

@@ -253,7 +253,9 @@ static void dumpDatabase(Archive *AH);
 static void dumpEncoding(Archive *AH);
 static void dumpStdStrings(Archive *AH);
 static void binary_upgrade_set_type_oids_by_type_oid(Archive *fout,
-										 PQExpBuffer upgrade_buffer, Oid pg_type_oid);
+										 PQExpBuffer upgrade_buffer,
+										 Oid pg_type_oid,
+										 bool force_array_type);
 static bool binary_upgrade_set_type_oids_by_rel_oid(Archive *fout,
 										PQExpBuffer upgrade_buffer, Oid pg_rel_oid);
 static void binary_upgrade_set_pg_class_oids(Archive *fout,
@@ -3949,10 +3951,11 @@ dumpSubscription(Archive *fout, SubscriptionInfo *subinfo)
 static void
 binary_upgrade_set_type_oids_by_type_oid(Archive *fout,
 										 PQExpBuffer upgrade_buffer,
-										 Oid pg_type_oid)
+										 Oid pg_type_oid,
+										 bool force_array_type)
 {
 	PQExpBuffer upgrade_query = createPQExpBuffer();
-	PGresult   *upgrade_res;
+	PGresult   *res;
 	Oid			pg_type_array_oid;
 
 	appendPQExpBufferStr(upgrade_buffer, "\n-- For binary upgrade, must preserve pg_type oid\n");
@@ -3964,12 +3967,43 @@ binary_upgrade_set_type_oids_by_type_oid(Archive *fout,
 	appendPQExpBuffer(upgrade_query,
 					  "SELECT typarray "
 					  "FROM pg_catalog.pg_type "
-					  "WHERE pg_type.oid = '%u'::pg_catalog.oid;",
+					  "WHERE oid = '%u'::pg_catalog.oid;",
 					  pg_type_oid);
 
-	upgrade_res = ExecuteSqlQueryForSingleRow(fout, upgrade_query->data);
+	res = ExecuteSqlQueryForSingleRow(fout, upgrade_query->data);
+
+	pg_type_array_oid = atooid(PQgetvalue(res, 0, PQfnumber(res, "typarray")));
 
-	pg_type_array_oid = atooid(PQgetvalue(upgrade_res, 0, PQfnumber(upgrade_res, "typarray")));
+	PQclear(res);
+
+	if (!OidIsValid(pg_type_array_oid) && force_array_type)
+	{
+		/*
+		 * If the old version didn't assign an array type, but the new version
+		 * does, we must select an unused type OID to assign.  This currently
+		 * only happens for domains, when upgrading pre-v11 to v11 and up.
+		 *
+		 * Note: local state here is kind of ugly, but we must have some,
+		 * since we mustn't choose the same unused OID more than once.
+		 */
+		static Oid	next_possible_free_oid = FirstNormalObjectId;
+		bool		is_dup;
+
+		do
+		{
+			++next_possible_free_oid;
+			printfPQExpBuffer(upgrade_query,
+							  "SELECT EXISTS(SELECT 1 "
+							  "FROM pg_catalog.pg_type "
+							  "WHERE oid = '%u'::pg_catalog.oid);",
+							  next_possible_free_oid);
+			res = ExecuteSqlQueryForSingleRow(fout, upgrade_query->data);
+			is_dup = (PQgetvalue(res, 0, 0)[0] == 't');
+			PQclear(res);
+		} while (is_dup);
+
+		pg_type_array_oid = next_possible_free_oid;
+	}
 
 	if (OidIsValid(pg_type_array_oid))
 	{
@@ -3980,7 +4014,6 @@ binary_upgrade_set_type_oids_by_type_oid(Archive *fout,
 						  pg_type_array_oid);
 	}
 
-	PQclear(upgrade_res);
 	destroyPQExpBuffer(upgrade_query);
 }
 
@@ -4008,7 +4041,7 @@ binary_upgrade_set_type_oids_by_rel_oid(Archive *fout,
 	pg_type_oid = atooid(PQgetvalue(upgrade_res, 0, PQfnumber(upgrade_res, "crel")));
 
 	binary_upgrade_set_type_oids_by_type_oid(fout, upgrade_buffer,
-											 pg_type_oid);
+											 pg_type_oid, false);
 
 	if (!PQgetisnull(upgrade_res, 0, PQfnumber(upgrade_res, "trel")))
 	{
@@ -9840,7 +9873,8 @@ dumpEnumType(Archive *fout, TypeInfo *tyinfo)
 
 	if (dopt->binary_upgrade)
 		binary_upgrade_set_type_oids_by_type_oid(fout, q,
-												 tyinfo->dobj.catId.oid);
+												 tyinfo->dobj.catId.oid,
+												 false);
 
 	appendPQExpBuffer(q, "CREATE TYPE %s AS ENUM (",
 					  qtypname);
@@ -9976,8 +10010,9 @@ dumpRangeType(Archive *fout, TypeInfo *tyinfo)
 					  qtypname);
 
 	if (dopt->binary_upgrade)
-		binary_upgrade_set_type_oids_by_type_oid(fout,
-												 q, tyinfo->dobj.catId.oid);
+		binary_upgrade_set_type_oids_by_type_oid(fout, q,
+												 tyinfo->dobj.catId.oid,
+												 false);
 
 	appendPQExpBuffer(q, "CREATE TYPE %s AS RANGE (",
 					  qtypname);
@@ -10091,8 +10126,9 @@ dumpUndefinedType(Archive *fout, TypeInfo *tyinfo)
 					  qtypname);
 
 	if (dopt->binary_upgrade)
-		binary_upgrade_set_type_oids_by_type_oid(fout,
-												 q, tyinfo->dobj.catId.oid);
+		binary_upgrade_set_type_oids_by_type_oid(fout, q,
+												 tyinfo->dobj.catId.oid,
+												 false);
 
 	appendPQExpBuffer(q, "CREATE TYPE %s;\n",
 					  qtypname);
@@ -10296,10 +10332,14 @@ dumpBaseType(Archive *fout, TypeInfo *tyinfo)
 	appendPQExpBuffer(delq, "%s CASCADE;\n",
 					  qtypname);
 
-	/* We might already have a shell type, but setting pg_type_oid is harmless */
+	/*
+	 * We might already have a shell type, but setting pg_type_oid is
+	 * harmless, and in any case we'd better set the array type OID.
+	 */
 	if (dopt->binary_upgrade)
 		binary_upgrade_set_type_oids_by_type_oid(fout, q,
-												 tyinfo->dobj.catId.oid);
+												 tyinfo->dobj.catId.oid,
+												 false);
 
 	appendPQExpBuffer(q,
 					  "CREATE TYPE %s (\n"
@@ -10490,7 +10530,8 @@ dumpDomain(Archive *fout, TypeInfo *tyinfo)
 
 	if (dopt->binary_upgrade)
 		binary_upgrade_set_type_oids_by_type_oid(fout, q,
-												 tyinfo->dobj.catId.oid);
+												 tyinfo->dobj.catId.oid,
+												 true); /* force array type */
 
 	qtypname = pg_strdup(fmtId(tyinfo->dobj.name));
 
@@ -10692,7 +10733,8 @@ dumpCompositeType(Archive *fout, TypeInfo *tyinfo)
 	if (dopt->binary_upgrade)
 	{
 		binary_upgrade_set_type_oids_by_type_oid(fout, q,
-												 tyinfo->dobj.catId.oid);
+												 tyinfo->dobj.catId.oid,
+												 false);
 		binary_upgrade_set_pg_class_oids(fout, q, tyinfo->typrelid, false);
 	}
 
@@ -10967,7 +11009,8 @@ dumpShellType(Archive *fout, ShellTypeInfo *stinfo)
 
 	if (dopt->binary_upgrade)
 		binary_upgrade_set_type_oids_by_type_oid(fout, q,
-												 stinfo->baseType->dobj.catId.oid);
+												 stinfo->baseType->dobj.catId.oid,
+												 false);
 
 	appendPQExpBuffer(q, "CREATE TYPE %s;\n",
 					  fmtId(stinfo->dobj.name));