Fix issue 1124: Segmentation fault when using specific tables

regress/expected/expr.out

@@ -6913,9 +6913,79 @@ SELECT * FROM cypher('graph_395', $$ MATCH (p:Project)-[:Has]->(t:Task)-[:Assign
  {"pn": "Project B", "tasks": [{"tn": "Task C", "users": [{"id": 1407374883553282, "label": "Person", "properties": {"age": 43, "name": "Bob"}}::vertex]}]}
 (2 rows)
 
+---
+--- Fix: Segmentation fault when using specific names for tables #1124
+---
+--- The following are just a few commands to test SQLValueFunction types
+---
+SELECT count(*) FROM CURRENT_ROLE;
+ count 
+-------
+     1
+(1 row)
+
+SELECT count(*) FROM CURRENT_USER;
+ count 
+-------
+     1
+(1 row)
+
+SELECT count(*) FROM USER;
+ count 
+-------
+     1
+(1 row)
+
+SELECT count(*) FROM SESSION_USER;
+ count 
+-------
+     1
+(1 row)
+
+SELECT * FROM CURRENT_CATALOG;
+  current_catalog   
+--------------------
+ contrib_regression
+(1 row)
+
+SELECT * FROM CURRENT_SCHEMA;
+ current_schema 
+----------------
+ ag_catalog
+(1 row)
+
+SELECT * FROM create_graph('issue_1124');
+NOTICE:  graph "issue_1124" has been created
+ create_graph 
+--------------
+
+(1 row)
+
+SELECT results, pg_typeof(user) FROM cypher('issue_1124', $$ CREATE (u) RETURN u $$) AS (results agtype), user;
+                            results                             | pg_typeof 
+----------------------------------------------------------------+-----------
+ {"id": 281474976710657, "label": "", "properties": {}}::vertex | name
+(1 row)
+
+SELECT results, pg_typeof(user) FROM cypher('issue_1124', $$ MATCH (u) RETURN u $$) AS (results agtype), user;
+                            results                             | pg_typeof 
+----------------------------------------------------------------+-----------
+ {"id": 281474976710657, "label": "", "properties": {}}::vertex | name
+(1 row)
+
 --
 -- Cleanup
 --
+SELECT * FROM drop_graph('issue_1124', true);
+NOTICE:  drop cascades to 2 other objects
+DETAIL:  drop cascades to table issue_1124._ag_label_vertex
+drop cascades to table issue_1124._ag_label_edge
+NOTICE:  graph "issue_1124" has been dropped
+ drop_graph 
+------------
+
+(1 row)
+
 SELECT * FROM drop_graph('graph_395', true);
 NOTICE:  drop cascades to 7 other objects
 DETAIL:  drop cascades to table graph_395._ag_label_vertex

regress/sql/expr.sql

@@ -2810,9 +2810,27 @@ SELECT * FROM cypher('graph_395', $$ MATCH (p:Project)-[:Has]->(t:Task)-[:Assign
                                      WITH p, collect(task) AS tasks
                                      WITH {pn: p.name, tasks:tasks} AS project
                                      RETURN project $$) AS (p agtype);
+
+---
+--- Fix: Segmentation fault when using specific names for tables #1124
+---
+--- The following are just a few commands to test SQLValueFunction types
+---
+
+SELECT count(*) FROM CURRENT_ROLE;
+SELECT count(*) FROM CURRENT_USER;
+SELECT count(*) FROM USER;
+SELECT count(*) FROM SESSION_USER;
+SELECT * FROM CURRENT_CATALOG;
+SELECT * FROM CURRENT_SCHEMA;
+SELECT * FROM create_graph('issue_1124');
+SELECT results, pg_typeof(user) FROM cypher('issue_1124', $$ CREATE (u) RETURN u $$) AS (results agtype), user;
+SELECT results, pg_typeof(user) FROM cypher('issue_1124', $$ MATCH (u) RETURN u $$) AS (results agtype), user;
+
 --
 -- Cleanup
 --
+SELECT * FROM drop_graph('issue_1124', true);
 SELECT * FROM drop_graph('graph_395', true);
 SELECT * FROM drop_graph('chained', true);
 SELECT * FROM drop_graph('VLE', true);

src/backend/parser/cypher_analyze.c

@@ -167,6 +167,21 @@ static bool convert_cypher_walker(Node *node, ParseState *pstate)
                      parser_errposition(pstate, exprLocation((Node *)funcexpr))));
         }
 
+        /*
+         * From PG -
+         * SQLValueFunction - parameterless functions with special grammar
+         *                    productions.
+         *
+         * These are a special case that needs to be ignored.
+         *
+         * TODO: This likely needs to be done with XmlExpr types, and maybe
+         *       a few others too.
+         */
+        if (IsA(funcexpr, SQLValueFunction))
+        {
+            return false;
+        }
+
         return expression_tree_walker((Node *)funcexpr->args,
                                       convert_cypher_walker, pstate);
     }
@@ -296,6 +311,21 @@ static bool is_rte_cypher(RangeTblEntry *rte)
  */
 static bool is_func_cypher(FuncExpr *funcexpr)
 {
+    /*
+     * From PG -
+     * SQLValueFunction - parameterless functions with special grammar
+     *                    productions.
+     *
+     * These are a special case that needs to be ignored.
+     *
+     *  TODO: This likely needs to be done with XmlExpr types, and maybe
+     *        a few others too.
+     */
+    if (IsA(funcexpr, SQLValueFunction))
+    {
+        return false;
+    }
+
     return is_oid_ag_func(funcexpr->funcid, "cypher");
 }