Fix confusion about the return rowtype of SQL-language procedures.

There is a very ancient hack in check_sql_fn_retval that allows a
single SELECT targetlist entry of composite type to be taken as
supplying all the output columns of a function returning composite.
(This is grotty and fundamentally ambiguous, but it's really hard
to do nested composite-returning functions without it.)

As far as I know, that doesn't cause any problems in ordinary
functions.  It's disastrous for procedures however.  All procedures
that have any output parameters are labeled with prorettype RECORD,
and the CALL code expects it will get back a record with one column
per output parameter, regardless of whether any of those parameters
is composite.  Doing something else leads to an assertion failure
or core dump.

This is simple enough to fix: we just need to not apply that rule
when considering procedures.  However, that requires adding another
argument to check_sql_fn_retval, which at least in principle might be
getting called by external callers.  Therefore, in the back branches
convert check_sql_fn_retval into an ABI-preserving wrapper around a
new function check_sql_fn_retval_ext.

Per report from Yahor Yuzefovich.  This has been broken since we
implemented procedures, so back-patch to all supported branches.

Discussion: https://postgr.es/m/CABz5gWHSjj2df6uG0NRiDhZ_Uz=Y8t0FJP-_SVSsRsnrQT76Gg@mail.gmail.com

diff --git a/src/backend/catalog/pg_proc.c b/src/backend/catalog/pg_proc.c
index 7514015549263317df429044bc122598b1b31b11..5fd8a385a570b27c5b397016dfdf24da1212b15c 100644 (file)
--- a/src/backend/catalog/pg_proc.c
+++ b/src/backend/catalog/pg_proc.c
@@ -972,9 +972,10 @@ fmgr_sql_validator(PG_FUNCTION_ARGS)
 
            (void) get_func_result_type(funcoid, &rettype, &rettupdesc);
 
-           (void) check_sql_fn_retval(querytree_list,
-                                      rettype, rettupdesc,
-                                      false, NULL);
+           (void) check_sql_fn_retval_ext(querytree_list,
+                                          rettype, rettupdesc,
+                                          proc->prokind,
+                                          false, NULL);
        }
 
        error_context_stack = sqlerrcontext.previous;

diff --git a/src/backend/executor/functions.c b/src/backend/executor/functions.c
index dd7418a4fc10aa71c6a9dbf8c2e8627da04f997d..63062a0b924000212a1e315eb79efdb7f4cc2a13 100644 (file)
--- a/src/backend/executor/functions.c
+++ b/src/backend/executor/functions.c
@@ -750,11 +750,12 @@ init_sql_fcache(FunctionCallInfo fcinfo, Oid collation, bool lazyEvalOK)
     * the rowtype column into multiple columns, since we have no way to
     * notify the caller that it should do that.)
     */
-   fcache->returnsTuple = check_sql_fn_retval(queryTree_list,
-                                              rettype,
-                                              rettupdesc,
-                                              false,
-                                              &resulttlist);
+   fcache->returnsTuple = check_sql_fn_retval_ext(queryTree_list,
+                                                  rettype,
+                                                  rettupdesc,
+                                                  procedureStruct->prokind,
+                                                  false,
+                                                  &resulttlist);
 
    /*
     * Construct a JunkFilter we can use to coerce the returned rowtype to the
@@ -1615,6 +1616,21 @@ check_sql_fn_retval(List *queryTreeLists,
                    Oid rettype, TupleDesc rettupdesc,
                    bool insertDroppedCols,
                    List **resultTargetList)
+{
+   /* Wrapper function to preserve ABI compatibility in released branches */
+   return check_sql_fn_retval_ext(queryTreeLists,
+                                  rettype, rettupdesc,
+                                  PROKIND_FUNCTION,
+                                  insertDroppedCols,
+                                  resultTargetList);
+}
+
+bool
+check_sql_fn_retval_ext(List *queryTreeLists,
+                       Oid rettype, TupleDesc rettupdesc,
+                       char prokind,
+                       bool insertDroppedCols,
+                       List **resultTargetList)
 {
    bool        is_tuple_result = false;
    Query      *parse;
@@ -1632,7 +1648,7 @@ check_sql_fn_retval(List *queryTreeLists,
 
    /*
     * If it's declared to return VOID, we don't care what's in the function.
-    * (This takes care of the procedure case, as well.)
+    * (This takes care of procedures with no output parameters, as well.)
     */
    if (rettype == VOIDOID)
        return false;
@@ -1787,8 +1803,13 @@ check_sql_fn_retval(List *queryTreeLists,
         * or not the record type really matches.  For the moment we rely on
         * runtime type checking to catch any discrepancy, but it'd be nice to
         * do better at parse time.
+        *
+        * We must *not* do this for a procedure, however.  Procedures with
+        * output parameter(s) have rettype RECORD, and the CALL code expects
+        * to get results corresponding to the list of output parameters, even
+        * when there's just one parameter that's composite.
         */
-       if (tlistlen == 1)
+       if (tlistlen == 1 && prokind != PROKIND_PROCEDURE)
        {
            TargetEntry *tle = (TargetEntry *) linitial(tlist);
 

diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
index 1b7aaf092cc2ab0f18e2c7c782f2bf001bb030e0..9d817747c883325435addd8b99a60cf6f16f1333 100644 (file)
--- a/src/backend/optimizer/util/clauses.c
+++ b/src/backend/optimizer/util/clauses.c
@@ -4622,9 +4622,10 @@ inline_function(Oid funcid, Oid result_type, Oid result_collid,
     * needed; that's probably not important, but let's be careful.
     */
    querytree_list = list_make1(querytree);
-   if (check_sql_fn_retval(list_make1(querytree_list),
-                           result_type, rettupdesc,
-                           false, NULL))
+   if (check_sql_fn_retval_ext(list_make1(querytree_list),
+                               result_type, rettupdesc,
+                               funcform->prokind,
+                               false, NULL))
        goto fail;              /* reject whole-tuple-result cases */
 
    /*
@@ -5173,9 +5174,10 @@ inline_set_returning_function(PlannerInfo *root, RangeTblEntry *rte)
     * shows it's returning a whole tuple result; otherwise what it's
     * returning is a single composite column which is not what we need.
     */
-   if (!check_sql_fn_retval(list_make1(querytree_list),
-                            fexpr->funcresulttype, rettupdesc,
-                            true, NULL) &&
+   if (!check_sql_fn_retval_ext(list_make1(querytree_list),
+                                fexpr->funcresulttype, rettupdesc,
+                                funcform->prokind,
+                                true, NULL) &&
        (functypclass == TYPEFUNC_COMPOSITE ||
         functypclass == TYPEFUNC_COMPOSITE_DOMAIN ||
         functypclass == TYPEFUNC_RECORD))

diff --git a/src/include/executor/functions.h b/src/include/executor/functions.h
index 4c20cf4df95fb12d3213e09fbb11b924680887d9..fda7424c53dc0bc3be9d80164c4c831f2afbe64a 100644 (file)
--- a/src/include/executor/functions.h
+++ b/src/include/executor/functions.h
@@ -50,6 +50,12 @@ extern bool check_sql_fn_retval(List *queryTreeLists,
                                bool insertDroppedCols,
                                List **resultTargetList);
 
+extern bool check_sql_fn_retval_ext(List *queryTreeLists,
+                                   Oid rettype, TupleDesc rettupdesc,
+                                   char prokind,
+                                   bool insertDroppedCols,
+                                   List **resultTargetList);
+
 extern DestReceiver *CreateSQLFunctionDestReceiver(void);
 
 #endif                         /* FUNCTIONS_H */

diff --git a/src/test/regress/expected/create_procedure.out b/src/test/regress/expected/create_procedure.out
index 46c827f9791c6b8e0803f15a2403fd76cdb2fe6d..f3eabc0a6a312f425b35f267ee3d9dde67b3b613 100644 (file)
--- a/src/test/regress/expected/create_procedure.out
+++ b/src/test/regress/expected/create_procedure.out
@@ -148,7 +148,19 @@ CALL ptest4a(a, b);  -- error, not supported
 $$;
 ERROR:  calling procedures with output arguments is not supported in SQL functions
 CONTEXT:  SQL function "ptest4b"
-DROP PROCEDURE ptest4a;
+-- we used to get confused by a single output argument that is composite
+CREATE PROCEDURE ptest4c(INOUT comp int8_tbl)
+LANGUAGE SQL
+AS $$
+SELECT ROW(1, 2);
+$$;
+CALL ptest4c(NULL);
+ comp  
+-------
+ (1,2)
+(1 row)
+
+DROP PROCEDURE ptest4a, ptest4c;
 -- named and default parameters
 CREATE OR REPLACE PROCEDURE ptest5(a int, b text, c int default 100)
 LANGUAGE SQL

diff --git a/src/test/regress/sql/create_procedure.sql b/src/test/regress/sql/create_procedure.sql
index 75cc0fcf2a6ce43bb7d6aff88f3e41b9a603d803..50a4d881f9441e3a8aab6596e7661da45d2de250 100644 (file)
--- a/src/test/regress/sql/create_procedure.sql
+++ b/src/test/regress/sql/create_procedure.sql
@@ -90,7 +90,16 @@ AS $$
 CALL ptest4a(a, b);  -- error, not supported
 $$;
 
-DROP PROCEDURE ptest4a;
+-- we used to get confused by a single output argument that is composite
+CREATE PROCEDURE ptest4c(INOUT comp int8_tbl)
+LANGUAGE SQL
+AS $$
+SELECT ROW(1, 2);
+$$;
+
+CALL ptest4c(NULL);
+
+DROP PROCEDURE ptest4a, ptest4c;
 
 
 -- named and default parameters