This patch addresses the problem mentioned in the "process crash

when a plpython function returns unicode" thread:

http://archives.postgresql.org/pgsql-bugs/2005-06/msg00105.php

In several places PL/Python was calling PyObject_Str() and then
PyString_AsString() without checking if the former had returned
NULL to indicate an error.  PyString_AsString() doesn't expect a
NULL argument, so passing one causes a segmentation fault.  This
patch adds checks for NULL and raises errors via PLy_elog(), which
prints details of the underlying Python exception.  The patch also
adds regression tests for these checks.  All tests pass on my
Solaris 9 box running HEAD and Python 2.4.1.

In one place the patch doesn't call PLy_elog() because that could
cause infinite recursion; see the comment I added.  I'm not sure
how to test that particular case or whether it's even possible to
get an error there: the value that the code should check is the
Python exception type, so I wonder if a NULL value "shouldn't
happen."  This patch converts NULL to "Unknown Exception" but I
wonder if an Assert() would be appropriate.

The patch is against HEAD but the same changes should be applied
to earlier versions because they have the same problem.  The patch
might not apply cleanly against earlier versions -- will the committer
take care of little differences or should I submit different versions
of the patch?

Michael Fuhr

1 files changed, 28 insertions, 0 deletions

diff --git a/src/pl/plpython/sql/plpython_function.sql b/src/pl/plpython/sql/plpython_function.sql
index 25ac388495a..e3ec2afe014 100644
--- a/src/pl/plpython/sql/plpython_function.sql
+++ b/src/pl/plpython/sql/plpython_function.sql
@@ -313,3 +313,31 @@ LANGUAGE plpythonu;
 CREATE OR REPLACE FUNCTION newline_crlf() RETURNS integer AS
 'x = 100\r\ny = 23\r\nreturn x + y\r\n'
 LANGUAGE plpythonu;
+
+--
+-- Unicode error handling
+--
+
+CREATE FUNCTION unicode_return_error() RETURNS text AS '
+return u"\\x80"
+' LANGUAGE plpythonu;
+
+CREATE FUNCTION unicode_trigger_error() RETURNS trigger AS '
+TD["new"]["testvalue"] = u"\\x80"
+return "MODIFY"
+' LANGUAGE plpythonu;
+
+CREATE TRIGGER unicode_test_bi BEFORE INSERT ON unicode_test
+  FOR EACH ROW EXECUTE PROCEDURE unicode_trigger_error();
+
+CREATE FUNCTION unicode_plan_error1() RETURNS text AS '
+plan = plpy.prepare("SELECT $1 AS testvalue", ["text"])
+rv = plpy.execute(plan, [u"\\x80"], 1)
+return rv[0]["testvalue"]
+' LANGUAGE plpythonu;
+
+CREATE FUNCTION unicode_plan_error2() RETURNS text AS '
+plan = plpy.prepare("SELECT $1 AS testvalue1, $2 AS testvalue2", ["text", "text"])
+rv = plpy.execute(plan, u"\\x80", 1)
+return rv[0]["testvalue1"]
+' LANGUAGE plpythonu;