Add support for PG17 (#2130)

- A new node type is introduced for JSON support, that is
  JsonConstructorExpr - wrapper over FuncExpr/Aggref/WindowFunc for
  SQL/JSON constructors.
- Added additional checks for JsonConstructorExpr expression node for
  which the walker would crash.
- Removed palloc0fast function call (which is not available in PG17)

Author: uhayat

src/backend/nodes/ag_nodes.c

@@ -156,7 +156,7 @@ ExtensibleNode *_new_ag_node(Size size, ag_node_tag tag)
 {
     ExtensibleNode *n;
 
-    n = (ExtensibleNode *)palloc0fast(size);
+    n = (ExtensibleNode *)palloc0(size);
     n->type = T_ExtensibleNode;
     n->extnodename = node_names[tag];
 

src/backend/parser/cypher_analyze.c

@@ -174,14 +174,17 @@ static bool convert_cypher_walker(Node *node, ParseState *pstate)
          * OpExpr - expression node for an operator invocation
          * Const - constant value or expression node
          * BoolExpr - expression node for the basic Boolean operators AND, OR, NOT
+         * JsonConstructorExpr - wrapper over FuncExpr/Aggref/WindowFunc for
+         *                       SQL/JSON constructors
          *
          * These are a special case that needs to be ignored.
          *
          */
         if (IsA(funcexpr, SQLValueFunction)
                 || IsA(funcexpr, CoerceViaIO)
                 || IsA(funcexpr, Var)   || IsA(funcexpr, OpExpr)
-                || IsA(funcexpr, Const) || IsA(funcexpr, BoolExpr))
+                || IsA(funcexpr, Const) || IsA(funcexpr, BoolExpr)
+                || IsA(funcexpr, JsonConstructorExpr))
         {
             return false;
         }
@@ -346,14 +349,17 @@ static bool is_func_cypher(FuncExpr *funcexpr)
      * OpExpr - expression node for an operator invocation
      * Const - constant value or expression node
      * BoolExpr - expression node for the basic Boolean operators AND, OR, NOT
+     * JsonConstructorExpr - wrapper over FuncExpr/Aggref/WindowFunc for
+     *                       SQL/JSON constructors
      *
      * These are a special case that needs to be ignored.
      *
      */
     if (IsA(funcexpr, SQLValueFunction)
             || IsA(funcexpr, CoerceViaIO)
             || IsA(funcexpr, Var)   || IsA(funcexpr, OpExpr)
-            || IsA(funcexpr, Const) || IsA(funcexpr, BoolExpr))
+            || IsA(funcexpr, Const) || IsA(funcexpr, BoolExpr)
+            || IsA(funcexpr, JsonConstructorExpr))
     {
         return false;
     }