Fix handling of polymorphic output arguments for procedures.

Most of the infrastructure for procedure arguments was already
okay with polymorphic output arguments, but it turns out that
CallStmtResultDesc() was a few bricks shy of a load here.  It thought
all it needed to do was call build_function_result_tupdesc_t, but
that function specifically disclaims responsibility for resolving
polymorphic arguments.  Failing to handle that doesn't seem to be
a problem for CALL in plpgsql, but CALL from plain SQL would get
errors like "cannot display a value of type anyelement", or even
crash outright.

In v14 and later we can simply examine the exposed types of the
CallStmt.outargs nodes to get the right type OIDs.  But it's a lot
more complicated to fix in v12/v13, because those versions don't
have CallStmt.outargs, nor do they do expand_function_arguments
until ExecuteCallStmt runs.  We have to duplicatively run
expand_function_arguments, and then re-determine which elements
of the args list are output arguments.

Per bug #18463 from Drew Kimball.  Back-patch to all supported
versions, since it's busted in all of them.

Discussion: https://postgr.es/m/18463-f8cd77e12564d8a2@postgresql.org

diff --git a/src/backend/commands/functioncmds.c b/src/backend/commands/functioncmds.c
index 016cdf20fb2df543a435d40fc1f744e5dc34350f..0434f197960b3d9bb8e4e56235150551d5cd2172 100644 (file)
--- a/src/backend/commands/functioncmds.c
+++ b/src/backend/commands/functioncmds.c
@@ -56,6 +56,7 @@
 #include "executor/functions.h"
 #include "funcapi.h"
 #include "miscadmin.h"
+#include "nodes/nodeFuncs.h"
 #include "optimizer/optimizer.h"
 #include "parser/analyze.h"
 #include "parser/parse_coerce.h"
@@ -2391,5 +2392,32 @@ CallStmtResultDesc(CallStmt *stmt)
 
    ReleaseSysCache(tuple);
 
+   /*
+    * The result of build_function_result_tupdesc_t has the right column
+    * names, but it just has the declared output argument types, which is the
+    * wrong thing in polymorphic cases.  Get the correct types by examining
+    * stmt->outargs.  We intentionally keep the atttypmod as -1 and the
+    * attcollation as the type's default, since that's always the appropriate
+    * thing for function outputs; there's no point in considering any
+    * additional info available from outargs.  Note that tupdesc is null if
+    * there are no outargs.
+    */
+   if (tupdesc)
+   {
+       Assert(tupdesc->natts == list_length(stmt->outargs));
+       for (int i = 0; i < tupdesc->natts; i++)
+       {
+           Form_pg_attribute att = TupleDescAttr(tupdesc, i);
+           Node       *outarg = (Node *) list_nth(stmt->outargs, i);
+
+           TupleDescInitEntry(tupdesc,
+                              i + 1,
+                              NameStr(att->attname),
+                              exprType(outarg),
+                              -1,
+                              0);
+       }
+   }
+
    return tupdesc;
 }

diff --git a/src/pl/plpgsql/src/expected/plpgsql_call.out b/src/pl/plpgsql/src/expected/plpgsql_call.out
index 25ad35d81407f8c6dc23d037bbb43db2d8156e44..5a99ac3bc7ce91ea9a910aaa27e51bba598f986d 100644 (file)
--- a/src/pl/plpgsql/src/expected/plpgsql_call.out
+++ b/src/pl/plpgsql/src/expected/plpgsql_call.out
@@ -397,6 +397,40 @@ END
 $$;
 NOTICE:  a: <NULL>, b: {30,7}
 NOTICE:  _a: 37, _b: 30, _c: 7
+-- polymorphic OUT arguments
+CREATE PROCEDURE test_proc12(a anyelement, OUT b anyelement, OUT c anyarray)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+  RAISE NOTICE 'a: %', a;
+  b := a;
+  c := array[a];
+END;
+$$;
+DO $$
+DECLARE _a int; _b int; _c int[];
+BEGIN
+  _a := 10;
+  CALL test_proc12(_a, _b, _c);
+  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;
+END
+$$;
+NOTICE:  a: 10
+NOTICE:  _a: 10, _b: 10, _c: {10}
+DO $$
+DECLARE _a int; _b int; _c text[];
+BEGIN
+  _a := 10;
+  CALL test_proc12(_a, _b, _c);  -- error
+  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;
+END
+$$;
+ERROR:  procedure test_proc12(integer, integer, text[]) does not exist
+LINE 1: CALL test_proc12(_a, _b, _c)
+             ^
+HINT:  No procedure matches the given name and argument types. You might need to add explicit type casts.
+QUERY:  CALL test_proc12(_a, _b, _c)
+CONTEXT:  PL/pgSQL function inline_code_block line 5 at CALL
 -- transition variable assignment
 TRUNCATE test1;
 CREATE FUNCTION triggerfunc1() RETURNS trigger

diff --git a/src/pl/plpgsql/src/sql/plpgsql_call.sql b/src/pl/plpgsql/src/sql/plpgsql_call.sql
index d80a5d2819e633f0e91c1349a721ae5e5d9e3f67..27624f1386d713b02cb381e1dd266fd7dcfde150 100644 (file)
--- a/src/pl/plpgsql/src/sql/plpgsql_call.sql
+++ b/src/pl/plpgsql/src/sql/plpgsql_call.sql
@@ -363,6 +363,36 @@ BEGIN
 END
 $$;
 
+-- polymorphic OUT arguments
+
+CREATE PROCEDURE test_proc12(a anyelement, OUT b anyelement, OUT c anyarray)
+LANGUAGE plpgsql
+AS $$
+BEGIN
+  RAISE NOTICE 'a: %', a;
+  b := a;
+  c := array[a];
+END;
+$$;
+
+DO $$
+DECLARE _a int; _b int; _c int[];
+BEGIN
+  _a := 10;
+  CALL test_proc12(_a, _b, _c);
+  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;
+END
+$$;
+
+DO $$
+DECLARE _a int; _b int; _c text[];
+BEGIN
+  _a := 10;
+  CALL test_proc12(_a, _b, _c);  -- error
+  RAISE NOTICE '_a: %, _b: %, _c: %', _a, _b, _c;
+END
+$$;
+
 
 -- transition variable assignment
 

diff --git a/src/test/regress/expected/create_procedure.out b/src/test/regress/expected/create_procedure.out
index f3eabc0a6a312f425b35f267ee3d9dde67b3b613..3281c9267345afcc88b0593db16934dd2ae25307 100644 (file)
--- a/src/test/regress/expected/create_procedure.out
+++ b/src/test/regress/expected/create_procedure.out
@@ -193,6 +193,40 @@ AS $$
 SELECT NULL::int;
 $$;
 CALL ptest6(1, 2);
+CREATE PROCEDURE ptest6a(inout a anyelement, out b anyelement)
+LANGUAGE SQL
+AS $$
+SELECT $1, $1;
+$$;
+CALL ptest6a(1, null);
+ a | b 
+---+---
+ 1 | 1
+(1 row)
+
+CALL ptest6a(1.1, null);
+  a  |  b  
+-----+-----
+ 1.1 | 1.1
+(1 row)
+
+CREATE PROCEDURE ptest6b(a anyelement, out b anyelement, out c anyarray)
+LANGUAGE SQL
+AS $$
+SELECT $1, array[$1];
+$$;
+CALL ptest6b(1, null, null);
+ b |  c  
+---+-----
+ 1 | {1}
+(1 row)
+
+CALL ptest6b(1.1, null, null);
+  b  |   c   
+-----+-------
+ 1.1 | {1.1}
+(1 row)
+
 -- collation assignment
 CREATE PROCEDURE ptest7(a text, b text)
 LANGUAGE SQL

diff --git a/src/test/regress/sql/create_procedure.sql b/src/test/regress/sql/create_procedure.sql
index 50a4d881f9441e3a8aab6596e7661da45d2de250..c617577992a67ddc5082fcf6677ce308ef9a5380 100644 (file)
--- a/src/test/regress/sql/create_procedure.sql
+++ b/src/test/regress/sql/create_procedure.sql
@@ -131,6 +131,24 @@ $$;
 
 CALL ptest6(1, 2);
 
+CREATE PROCEDURE ptest6a(inout a anyelement, out b anyelement)
+LANGUAGE SQL
+AS $$
+SELECT $1, $1;
+$$;
+
+CALL ptest6a(1, null);
+CALL ptest6a(1.1, null);
+
+CREATE PROCEDURE ptest6b(a anyelement, out b anyelement, out c anyarray)
+LANGUAGE SQL
+AS $$
+SELECT $1, array[$1];
+$$;
+
+CALL ptest6b(1, null, null);
+CALL ptest6b(1.1, null, null);
+
 
 -- collation assignment