Fix issue with adaptation of empty arrays in pg

docs/contents/changelog.rst

@@ -15,6 +15,7 @@ Version 5.0.1
   on the mailing list by Justin Pryzby).
 - Allow extra values that are not used in the command in the parameter dict
   passed to the query_formatted() method (as suggested by Justin Pryzby).
+- Improved handling of empty arrays in the classic module.
 - Unused classic connections were not properly garbage collected which could
   cause memory leaks (reported by Justin Pryzby).
 - Made C extension compatible with MSVC 9 again (this was needed to compile for

pg.py

@@ -517,7 +517,7 @@ def guess_simple_type(cls, value):
         if isinstance(value, (date, time, datetime, timedelta)):
             return 'date'
         if isinstance(value, list):
-            return '%s[]' % cls.guess_simple_base_type(value)
+            return '%s[]' % (cls.guess_simple_base_type(value) or 'text',)
         if isinstance(value, tuple):
             simple_type = cls.simple_type
             typ = simple_type('record')

tests/test_classic_dbwrapper.py

@@ -929,6 +929,18 @@ def testQueryFormatted(self):
         r = q.getresult()[0][0]
         self.assertEqual(r, 'alphabetagammadeltaepsilon')
 
+    def testQueryFormattedWithAny(self):
+        f = self.db.query_formatted
+        q = "select 2 = any(%s)"
+        r = f(q, [[1, 3]]).getresult()[0][0]
+        self.assertEqual(r, False if pg.get_bool() else 'f')
+        r = f(q, [[1, 2, 3]]).getresult()[0][0]
+        self.assertEqual(r, True if pg.get_bool() else 't')
+        r = f(q, [[]]).getresult()[0][0]
+        self.assertEqual(r, False if pg.get_bool() else 'f')
+        r = f(q, [[None]]).getresult()[0][0]
+        self.assertIsNone(r)
+
     def testPkey(self):
         query = self.db.query
         pkey = self.db.pkey