Add copy/equal support for XID lists

Commit f10a025cfe97 added support for List to store Xids, but didn't
handle the new type in all cases.  Add some obviously necessary pieces.
As far as I am aware, this is all dead code as far as core code is
concerned, but it seems unacceptable not to have it in case third-party
code wants to rely on this type of list.  (Some parts of the List API
remain unimplemented, but that can be fixed as and when needed -- see
lack of list_intersection_oid, list_deduplicate_int as precedents.)

Discussion: https://postgr.es/m/20220708164534.nbejhgt4ajz35p65@alvherre.pgsql

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index b8e40a4195ac6884903716fb41a9a682cd9d3802..e76fda8eba3cfcaa6519856d4db7eee59786eea9 100644 (file)
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -187,11 +187,12 @@ copyObjectImpl(const void *from)
            break;
 
            /*
-            * Lists of integers and OIDs don't need to be deep-copied, so we
-            * perform a shallow copy via list_copy()
+            * Lists of integers, OIDs and XIDs don't need to be deep-copied,
+            * so we perform a shallow copy via list_copy()
             */
        case T_IntList:
        case T_OidList:
+       case T_XidList:
            retval = list_copy(from);
            break;
 

diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 8d54e1a4866800b27372fa439eb5142bed42eab7..0373aa30fe9fd1bcc91023188bb279507911d087 100644 (file)
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -188,6 +188,13 @@ _equalList(const List *a, const List *b)
                    return false;
            }
            break;
+       case T_XidList:
+           forboth(item_a, a, item_b, b)
+           {
+               if (lfirst_xid(item_a) != lfirst_xid(item_b))
+                   return false;
+           }
+           break;
        default:
            elog(ERROR, "unrecognized list node type: %d",
                 (int) a->type);
@@ -238,6 +245,7 @@ equal(const void *a, const void *b)
        case T_List:
        case T_IntList:
        case T_OidList:
+       case T_XidList:
            retval = _equalList(a, b);
            break;
 

diff --git a/src/test/modules/test_oat_hooks/test_oat_hooks.c b/src/test/modules/test_oat_hooks/test_oat_hooks.c
index 0ad77e743de00f914a5739f4280a1298f8152840..1f40d632e07970d1f0d3d375196bef3f97fbecac 100644 (file)
--- a/src/test/modules/test_oat_hooks/test_oat_hooks.c
+++ b/src/test/modules/test_oat_hooks/test_oat_hooks.c
@@ -1122,6 +1122,9 @@ nodetag_to_string(NodeTag tag)
        case T_OidList:
            return "OidList";
            break;
+       case T_XidList:
+           return "XidList";
+           break;
        case T_ExtensibleNode:
            return "ExtensibleNode";
            break;