Add concept of invalid value to SysCacheIdentifier

This commit tweaks the generation of the syscache IDs for the enum
SysCacheIdentifier to now include an invalid value, with -1 assigned as
value.  The concept of an invalid syscache ID exists when handling
lookups of a ObjectAddress, based on their set of properties in
ObjectPropertyType.  -1 is used for the case where an object type has no
option for a syscache lookup.

This has been found as independently useful while discussing a switch of
SysCacheIdentifier to a typedef, as we already have places that want to
know about the concept of an invalid value when dealing with
ObjectAddresses.

Reviewed-by: Andreas Karlsson <andreas@proxel.se>
Discussion: https://postgr.es/m/aZQRnmp9nVjtxAHS@paquier.xyz

src/backend/catalog/aclchk.c

@@ -4101,7 +4101,7 @@ object_ownercheck(Oid classid, Oid objectid, Oid roleid)
 		classid = LargeObjectMetadataRelationId;
 
 	cacheid = get_object_catcache_oid(classid);
-	if (cacheid != -1)
+	if (cacheid != SYSCACHEID_INVALID)
 	{
 		/* we can get the object's tuple from the syscache */
 		HeapTuple	tuple;

src/backend/catalog/genbki.pl

@@ -797,7 +797,7 @@ print $fk_info "};\n\n#endif\t\t\t\t\t\t\t/* SYSTEM_FK_INFO_H */\n";
 print_boilerplate($syscache_ids_fh, "syscache_ids.h", "SysCache identifiers");
 print $syscache_ids_fh "enum SysCacheIdentifier
 {
-";
+\tSYSCACHEID_INVALID = -1,\n";
 
 print_boilerplate($syscache_info_fh, "syscache_info.h",
 	"SysCache definitions");
@@ -812,7 +812,14 @@ print $syscache_info_fh "static const struct cachedesc cacheinfo[] = {\n";
 my $last_syscache;
 foreach my $syscache (sort keys %syscaches)
 {
-	print $syscache_ids_fh "\t$syscache,\n";
+	if (not defined $last_syscache)
+	{
+		print $syscache_ids_fh "\t$syscache = 0,\n";
+	}
+	else
+	{
+		print $syscache_ids_fh "\t$syscache,\n";
+	}
 	$last_syscache = $syscache;
 
 	print $syscache_info_fh "\t[$syscache] = {\n";

src/backend/catalog/objectaddress.c

@@ -135,8 +135,8 @@ static const ObjectPropertyType ObjectProperty[] =
 		"access method operator",
 		AccessMethodOperatorRelationId,
 		AccessMethodOperatorOidIndexId,
-		-1,
-		-1,
+		SYSCACHEID_INVALID,
+		SYSCACHEID_INVALID,
 		Anum_pg_amop_oid,
 		InvalidAttrNumber,
 		InvalidAttrNumber,
@@ -149,8 +149,8 @@ static const ObjectPropertyType ObjectProperty[] =
 		"access method procedure",
 		AccessMethodProcedureRelationId,
 		AccessMethodProcedureOidIndexId,
-		-1,
-		-1,
+		SYSCACHEID_INVALID,
+		SYSCACHEID_INVALID,
 		Anum_pg_amproc_oid,
 		InvalidAttrNumber,
 		InvalidAttrNumber,
@@ -163,8 +163,8 @@ static const ObjectPropertyType ObjectProperty[] =
 		"cast",
 		CastRelationId,
 		CastOidIndexId,
-		-1,
-		-1,
+		SYSCACHEID_INVALID,
+		SYSCACHEID_INVALID,
 		Anum_pg_cast_oid,
 		InvalidAttrNumber,
 		InvalidAttrNumber,
@@ -178,7 +178,7 @@ static const ObjectPropertyType ObjectProperty[] =
 		CollationRelationId,
 		CollationOidIndexId,
 		COLLOID,
-		-1,						/* COLLNAMEENCNSP also takes encoding */
+		SYSCACHEID_INVALID,		/* COLLNAMEENCNSP also takes encoding */
 		Anum_pg_collation_oid,
 		Anum_pg_collation_collname,
 		Anum_pg_collation_collnamespace,
@@ -192,7 +192,7 @@ static const ObjectPropertyType ObjectProperty[] =
 		ConstraintRelationId,
 		ConstraintOidIndexId,
 		CONSTROID,
-		-1,
+		SYSCACHEID_INVALID,
 		Anum_pg_constraint_oid,
 		Anum_pg_constraint_conname,
 		Anum_pg_constraint_connamespace,
@@ -220,7 +220,7 @@ static const ObjectPropertyType ObjectProperty[] =
 		DatabaseRelationId,
 		DatabaseOidIndexId,
 		DATABASEOID,
-		-1,
+		SYSCACHEID_INVALID,
 		Anum_pg_database_oid,
 		Anum_pg_database_datname,
 		InvalidAttrNumber,
@@ -233,8 +233,8 @@ static const ObjectPropertyType ObjectProperty[] =
 		"default ACL",
 		DefaultAclRelationId,
 		DefaultAclOidIndexId,
-		-1,
-		-1,
+		SYSCACHEID_INVALID,
+		SYSCACHEID_INVALID,
 		Anum_pg_default_acl_oid,
 		InvalidAttrNumber,
 		InvalidAttrNumber,
@@ -247,8 +247,8 @@ static const ObjectPropertyType ObjectProperty[] =
 		"extension",
 		ExtensionRelationId,
 		ExtensionOidIndexId,
-		-1,
-		-1,
+		SYSCACHEID_INVALID,
+		SYSCACHEID_INVALID,
 		Anum_pg_extension_oid,
 		Anum_pg_extension_extname,
 		InvalidAttrNumber,		/* extension doesn't belong to extnamespace */
@@ -290,7 +290,7 @@ static const ObjectPropertyType ObjectProperty[] =
 		ProcedureRelationId,
 		ProcedureOidIndexId,
 		PROCOID,
-		-1,						/* PROCNAMEARGSNSP also takes argument types */
+		SYSCACHEID_INVALID,		/* PROCNAMEARGSNSP also takes argument types */
 		Anum_pg_proc_oid,
 		Anum_pg_proc_proname,
 		Anum_pg_proc_pronamespace,
@@ -317,8 +317,8 @@ static const ObjectPropertyType ObjectProperty[] =
 		"large object metadata",
 		LargeObjectMetadataRelationId,
 		LargeObjectMetadataOidIndexId,
-		-1,
-		-1,
+		SYSCACHEID_INVALID,
+		SYSCACHEID_INVALID,
 		Anum_pg_largeobject_metadata_oid,
 		InvalidAttrNumber,
 		InvalidAttrNumber,
@@ -332,7 +332,7 @@ static const ObjectPropertyType ObjectProperty[] =
 		OperatorClassRelationId,
 		OpclassOidIndexId,
 		CLAOID,
-		-1,						/* CLAAMNAMENSP also takes opcmethod */
+		SYSCACHEID_INVALID,		/* CLAAMNAMENSP also takes opcmethod */
 		Anum_pg_opclass_oid,
 		Anum_pg_opclass_opcname,
 		Anum_pg_opclass_opcnamespace,
@@ -346,7 +346,7 @@ static const ObjectPropertyType ObjectProperty[] =
 		OperatorRelationId,
 		OperatorOidIndexId,
 		OPEROID,
-		-1,						/* OPERNAMENSP also takes left and right type */
+		SYSCACHEID_INVALID,		/* OPERNAMENSP also takes left and right type */
 		Anum_pg_operator_oid,
 		Anum_pg_operator_oprname,
 		Anum_pg_operator_oprnamespace,
@@ -360,7 +360,7 @@ static const ObjectPropertyType ObjectProperty[] =
 		OperatorFamilyRelationId,
 		OpfamilyOidIndexId,
 		OPFAMILYOID,
-		-1,						/* OPFAMILYAMNAMENSP also takes opfmethod */
+		SYSCACHEID_INVALID,		/* OPFAMILYAMNAMENSP also takes opfmethod */
 		Anum_pg_opfamily_oid,
 		Anum_pg_opfamily_opfname,
 		Anum_pg_opfamily_opfnamespace,
@@ -387,8 +387,8 @@ static const ObjectPropertyType ObjectProperty[] =
 		"role membership",
 		AuthMemRelationId,
 		AuthMemOidIndexId,
-		-1,
-		-1,
+		SYSCACHEID_INVALID,
+		SYSCACHEID_INVALID,
 		Anum_pg_auth_members_oid,
 		InvalidAttrNumber,
 		InvalidAttrNumber,
@@ -401,8 +401,8 @@ static const ObjectPropertyType ObjectProperty[] =
 		"rule",
 		RewriteRelationId,
 		RewriteOidIndexId,
-		-1,
-		-1,
+		SYSCACHEID_INVALID,
+		SYSCACHEID_INVALID,
 		Anum_pg_rewrite_oid,
 		Anum_pg_rewrite_rulename,
 		InvalidAttrNumber,
@@ -444,7 +444,7 @@ static const ObjectPropertyType ObjectProperty[] =
 		TableSpaceRelationId,
 		TablespaceOidIndexId,
 		TABLESPACEOID,
-		-1,
+		SYSCACHEID_INVALID,
 		Anum_pg_tablespace_oid,
 		Anum_pg_tablespace_spcname,
 		InvalidAttrNumber,
@@ -458,7 +458,7 @@ static const ObjectPropertyType ObjectProperty[] =
 		TransformRelationId,
 		TransformOidIndexId,
 		TRFOID,
-		-1,
+		SYSCACHEID_INVALID,
 		Anum_pg_transform_oid,
 		InvalidAttrNumber,
 		InvalidAttrNumber,
@@ -471,8 +471,8 @@ static const ObjectPropertyType ObjectProperty[] =
 		"trigger",
 		TriggerRelationId,
 		TriggerOidIndexId,
-		-1,
-		-1,
+		SYSCACHEID_INVALID,
+		SYSCACHEID_INVALID,
 		Anum_pg_trigger_oid,
 		Anum_pg_trigger_tgname,
 		InvalidAttrNumber,
@@ -485,8 +485,8 @@ static const ObjectPropertyType ObjectProperty[] =
 		"policy",
 		PolicyRelationId,
 		PolicyOidIndexId,
-		-1,
-		-1,
+		SYSCACHEID_INVALID,
+		SYSCACHEID_INVALID,
 		Anum_pg_policy_oid,
 		Anum_pg_policy_polname,
 		InvalidAttrNumber,
@@ -626,7 +626,7 @@ static const ObjectPropertyType ObjectProperty[] =
 		UserMappingRelationId,
 		UserMappingOidIndexId,
 		USERMAPPINGOID,
-		-1,
+		SYSCACHEID_INVALID,
 		Anum_pg_user_mapping_oid,
 		InvalidAttrNumber,
 		InvalidAttrNumber,
@@ -2583,7 +2583,7 @@ get_object_namespace(const ObjectAddress *address)
 
 	/* Currently, we can only handle object types with system caches. */
 	cache = property->oid_catcache_id;
-	Assert(cache != -1);
+	Assert(cache != SYSCACHEID_INVALID);
 
 	/* Fetch tuple from syscache and extract namespace attribute. */
 	tuple = SearchSysCache1(cache, ObjectIdGetDatum(address->objectId));