Dropped correct roundtrip of empty array

The feature in itself is not extremely useful and instead PostgreSQL is
not always able to cast away from text[], which is a regression see
(ticket #42).

NEWS

@@ -17,7 +17,6 @@ What's new in psycopg 2.4
     missing encodings: EUC_CN, EUC_JIS_2004, ISO885910, ISO885916,
     LATIN10, SHIFT_JIS_2004.
   - Dropped repeated dictionary lookups with unicode query/parameters.
-  - Empty lists correctly roundtrip Python -> PostgreSQL -> Python.
 
 * Bug fixes:
 

psycopg/adapter_list.c

@@ -45,7 +45,7 @@ list_quote(listObject *self)
 
     /* empty arrays are converted to NULLs (still searching for a way to
        insert an empty array in postgresql */
-    if (len == 0) return Bytes_FromString("'{}'::text[]");
+    if (len == 0) return Bytes_FromString("'{}'");
 
     tmp = PyTuple_New(len);
 

tests/types_basic.py

@@ -152,13 +152,25 @@ class TypesBasicTests(unittest.TestCase):
             self.assertEqual(s, buf2)
 
     def testArray(self):
-        s = self.execute("SELECT %s AS foo", ([],))
-        self.failUnlessEqual(s, [])
         s = self.execute("SELECT %s AS foo", ([[1,2],[3,4]],))
         self.failUnlessEqual(s, [[1,2],[3,4]])
         s = self.execute("SELECT %s AS foo", (['one', 'two', 'three'],))
         self.failUnlessEqual(s, ['one', 'two', 'three'])
 
+    def testEmptyArrayRegression(self):
+        # ticket #42
+        import datetime
+        curs = self.conn.cursor()
+        curs.execute("create table array_test (id integer, col timestamp without time zone[])")
+
+        curs.execute("insert into array_test values (%s, %s)", (1, [datetime.date(2011,2,14)]))
+        curs.execute("select col from array_test where id = 1")
+        self.assertEqual(curs.fetchone()[0], [datetime.datetime(2011, 2, 14, 0, 0)])
+
+        curs.execute("insert into array_test values (%s, %s)", (2, []))
+        curs.execute("select col from array_test where id = 2")
+        self.assertEqual(curs.fetchone()[0], [])
+
     @testutils.skip_on_python3
     def testTypeRoundtripBuffer(self):
         o1 = buffer("".join(map(chr, range(256))))