Re: SQL:2023 JSON simplified accessor support - Mailing list pgsql-hackers

On Aug 27, 2025, at 15:26, Chao Li <li.evan.chao@gmail.com> wrote:

diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h

index f7d07c84542..58a4b9df157 100644

--- a/src/include/parser/parse_node.h

+++ b/src/include/parser/parse_node.h

@@ -361,7 +361,7 @@ extern SubscriptingRef *transformContainerSubscripts(ParseState *pstate,

                                                                                                         Node *containerBase,

                                                                                                         Oid containerType,

                                                                                                         int32 containerTypMod,

-                                                                                                        List *indirection,

+                                                                                                        List **indirection,

                                                                                                         bool isAssignment);

Here we change “indirection” from * to **, I guess the reason is to indicate if the indirection list is fully processed. In case of fully processed, set it to NULL, then caller gets NULL via **.

As “indirection” is of type “List *”, can we just set “indirection->length = 0”? I checked pg_list.h, there is not a function or macro to cleanup a list (free elements and reset length to 0). There is a “list_free(List *list)”, but it will free “list” itself as well. Maybe we can add a new function, say “list_reset(List *list)” or “list_cleanup(List *list)”. This way will keep the function interface unchanged, and less changes would be involved.