Fix Issue 2256: segmentation fault when calling coalesce function

regress/expected/cypher.out

@@ -169,6 +169,22 @@ CREATE TABLE my_edges AS
 -- create a table of 4 columns, u, e, v, p. should be 5 rows
 CREATE TABLE my_detailed_paths AS
     (SELECT * FROM cypher('issue_1767', $$ MATCH p=(u)-[e]->(v) RETURN u,e,v,p $$) as (u agtype, e agtype, v agtype, p agtype));
+--
+-- Issue 2256: A segmentation fault occurs when calling the coalesce function
+--             This also occurs with the greatest function too.
+--
+SELECT * FROM coalesce(1, 0);
+ coalesce 
+----------
+        1
+(1 row)
+
+SELECT * FROM greatest(1, 0);
+ greatest 
+----------
+        1
+(1 row)
+
 -- dump out the tables
 SELECT * FROM my_vertices;
                                u                                

regress/sql/cypher.sql

@@ -94,6 +94,13 @@ CREATE TABLE my_edges AS
 CREATE TABLE my_detailed_paths AS
     (SELECT * FROM cypher('issue_1767', $$ MATCH p=(u)-[e]->(v) RETURN u,e,v,p $$) as (u agtype, e agtype, v agtype, p agtype));
 
+--
+-- Issue 2256: A segmentation fault occurs when calling the coalesce function
+--             This also occurs with the greatest function too.
+--
+SELECT * FROM coalesce(1, 0);
+SELECT * FROM greatest(1, 0);
+
 -- dump out the tables
 SELECT * FROM my_vertices;
 SELECT * FROM my_edges;

src/backend/parser/cypher_analyze.c

@@ -171,14 +171,20 @@ static bool convert_cypher_walker(Node *node, ParseState *pstate)
          * JsonConstructorExpr - wrapper over FuncExpr/Aggref/WindowFunc for
          *                       SQL/JSON constructors
          *
-         * These are a special case that needs to be ignored.
+         * Added the following, although only the first 2 caused crashes in tests -
+         * CoalesceExpr, MinMaxExpr, CaseExpr, XmlExpr, ArrayExpr, RowExpr
+         *
+         * These are all 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, JsonConstructorExpr))
+            || IsA(funcexpr, CoerceViaIO)
+            || IsA(funcexpr, Var)   || IsA(funcexpr, OpExpr)
+            || IsA(funcexpr, Const) || IsA(funcexpr, BoolExpr)
+            || IsA(funcexpr, JsonConstructorExpr)
+            || IsA(funcexpr, CoalesceExpr) || IsA(funcexpr, MinMaxExpr)
+            || IsA(funcexpr, CaseExpr) || IsA(funcexpr, XmlExpr)
+            || IsA(funcexpr, ArrayExpr) || IsA(funcexpr, RowExpr))
         {
             return false;
         }
@@ -346,14 +352,20 @@ static bool is_func_cypher(FuncExpr *funcexpr)
      * JsonConstructorExpr - wrapper over FuncExpr/Aggref/WindowFunc for
      *                       SQL/JSON constructors
      *
-     * These are a special case that needs to be ignored.
+     * Added the following, although only the first 2 caused crashes in tests -
+     * CoalesceExpr, MinMaxExpr, CaseExpr, XmlExpr, ArrayExpr, RowExpr
+     *
+     * These are all 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, JsonConstructorExpr))
+            || IsA(funcexpr, JsonConstructorExpr)
+            || IsA(funcexpr, CoalesceExpr) || IsA(funcexpr, MinMaxExpr)
+            || IsA(funcexpr, CaseExpr) || IsA(funcexpr, XmlExpr)
+            || IsA(funcexpr, ArrayExpr) || IsA(funcexpr, RowExpr))
     {
         return false;
     }