From ae58f1430abb4b0c309c40b377f91bf9d080334b Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 12 Jun 2015 13:44:06 -0400
Subject: [PATCH] Fix failure to cover scalar-vs-rowtype cases in
exec_stmt_return().
In commit 9e3ad1aac52454569393a947c06be0d301749362 I modified plpgsql
to use exec_stmt_return's simple-variables fast path in more cases.
However, I overlooked that there are really two different return
conventions in use here, depending on whether estate->retistuple is true,
and the existing fast-path code had only bothered to handle one of them.
So trying to return a scalar in a function returning composite, or vice
versa, could lead to unexpected error messages (typically "cache lookup
failed for type 0") or to a null-pointer-dereference crash.
In the DTYPE_VAR case, we can just throw error if retistuple is true,
corresponding to what happens in the general-expression code path that was
being used previously. (Perhaps someday both of these code paths should
attempt a coercion, but today is not that day.)
In the REC and ROW cases, just hand the problem to exec_eval_datum()
when not retistuple. Also clean up the ROW coding slightly so it looks
more like exec_eval_datum().
The previous commit also caused exec_stmt_return_next() to be used in
more cases, but that code seems to be OK as-is.
Per off-list report from Serge Rielau. This bug is new in 9.5 so no need
to back-patch.
---
src/pl/plpgsql/src/pl_exec.c | 58 ++++++++++++++++++++++-----
src/test/regress/expected/plpgsql.out | 32 +++++++++++++++
src/test/regress/sql/plpgsql.sql | 33 +++++++++++++++
3 files changed, 112 insertions(+), 11 deletions(-)
diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c
index aac7cdaf7cb..79dd6a22fce 100644
--- a/src/pl/plpgsql/src/pl_exec.c
+++ b/src/pl/plpgsql/src/pl_exec.c
@@ -2508,6 +2508,7 @@ exec_stmt_return(PLpgSQL_execstate *estate, PLpgSQL_stmt_return *stmt)
estate->retval = (Datum) 0;
estate->rettupdesc = NULL;
estate->retisnull = true;
+ estate->rettype = InvalidOid;
/*
* Special case path when the RETURN expression is a simple variable
@@ -2534,18 +2535,40 @@ exec_stmt_return(PLpgSQL_execstate *estate, PLpgSQL_stmt_return *stmt)
estate->retval = var->value;
estate->retisnull = var->isnull;
estate->rettype = var->datatype->typoid;
+
+ /*
+ * Cope with retistuple case. A PLpgSQL_var could not be
+ * of composite type, so we needn't make any effort to
+ * convert. However, for consistency with the expression
+ * code path, don't throw error if the result is NULL.
+ */
+ if (estate->retistuple && !estate->retisnull)
+ ereport(ERROR,
+ (errcode(ERRCODE_DATATYPE_MISMATCH),
+ errmsg("cannot return non-composite value from function returning composite type")));
}
break;
case PLPGSQL_DTYPE_REC:
{
PLpgSQL_rec *rec = (PLpgSQL_rec *) retvar;
+ int32 rettypmod;
if (HeapTupleIsValid(rec->tup))
{
- estate->retval = PointerGetDatum(rec->tup);
- estate->rettupdesc = rec->tupdesc;
- estate->retisnull = false;
+ if (estate->retistuple)
+ {
+ estate->retval = PointerGetDatum(rec->tup);
+ estate->rettupdesc = rec->tupdesc;
+ estate->retisnull = false;
+ }
+ else
+ exec_eval_datum(estate,
+ retvar,
+ &estate->rettype,
+ &rettypmod,
+ &estate->retval,
+ &estate->retisnull);
}
}
break;
@@ -2553,15 +2576,28 @@ exec_stmt_return(PLpgSQL_execstate *estate, PLpgSQL_stmt_return *stmt)
case PLPGSQL_DTYPE_ROW:
{
PLpgSQL_row *row = (PLpgSQL_row *) retvar;
+ int32 rettypmod;
- Assert(row->rowtupdesc);
- estate->retval =
- PointerGetDatum(make_tuple_from_row(estate, row,
- row->rowtupdesc));
- if (DatumGetPointer(estate->retval) == NULL) /* should not happen */
- elog(ERROR, "row not compatible with its own tupdesc");
- estate->rettupdesc = row->rowtupdesc;
- estate->retisnull = false;
+ if (estate->retistuple)
+ {
+ HeapTuple tup;
+
+ if (!row->rowtupdesc) /* should not happen */
+ elog(ERROR, "row variable has no tupdesc");
+ tup = make_tuple_from_row(estate, row, row->rowtupdesc);
+ if (tup == NULL) /* should not happen */
+ elog(ERROR, "row not compatible with its own tupdesc");
+ estate->retval = PointerGetDatum(tup);
+ estate->rettupdesc = row->rowtupdesc;
+ estate->retisnull = false;
+ }
+ else
+ exec_eval_datum(estate,
+ retvar,
+ &estate->rettype,
+ &rettypmod,
+ &estate->retval,
+ &estate->retisnull);
}
break;
diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out
index 78e5a85810e..7ce5415f053 100644
--- a/src/test/regress/expected/plpgsql.out
+++ b/src/test/regress/expected/plpgsql.out
@@ -4001,6 +4001,38 @@ $$ language plpgsql;
select compos();
ERROR: cannot return non-composite value from function returning composite type
CONTEXT: PL/pgSQL function compos() line 3 at RETURN
+-- RETURN variable is a different code path ...
+create or replace function compos() returns compostype as $$
+declare x int := 42;
+begin
+ return x;
+end;
+$$ language plpgsql;
+select * from compos();
+ERROR: cannot return non-composite value from function returning composite type
+CONTEXT: PL/pgSQL function compos() line 4 at RETURN
+drop function compos();
+-- test: invalid use of composite variable in scalar-returning function
+create or replace function compos() returns int as $$
+declare
+ v compostype;
+begin
+ v := (1, 'hello');
+ return v;
+end;
+$$ language plpgsql;
+select compos();
+ERROR: invalid input syntax for integer: "(1,hello)"
+CONTEXT: PL/pgSQL function compos() while casting return value to function's return type
+-- test: invalid use of composite expression in scalar-returning function
+create or replace function compos() returns int as $$
+begin
+ return (1, 'hello')::compostype;
+end;
+$$ language plpgsql;
+select compos();
+ERROR: invalid input syntax for integer: "(1,hello)"
+CONTEXT: PL/pgSQL function compos() while casting return value to function's return type
drop function compos();
drop type compostype;
--
diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql
index e19e4153867..aaf3e8479fe 100644
--- a/src/test/regress/sql/plpgsql.sql
+++ b/src/test/regress/sql/plpgsql.sql
@@ -3248,6 +3248,39 @@ $$ language plpgsql;
select compos();
+-- RETURN variable is a different code path ...
+create or replace function compos() returns compostype as $$
+declare x int := 42;
+begin
+ return x;
+end;
+$$ language plpgsql;
+
+select * from compos();
+
+drop function compos();
+
+-- test: invalid use of composite variable in scalar-returning function
+create or replace function compos() returns int as $$
+declare
+ v compostype;
+begin
+ v := (1, 'hello');
+ return v;
+end;
+$$ language plpgsql;
+
+select compos();
+
+-- test: invalid use of composite expression in scalar-returning function
+create or replace function compos() returns int as $$
+begin
+ return (1, 'hello')::compostype;
+end;
+$$ language plpgsql;
+
+select compos();
+
drop function compos();
drop type compostype;
--
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