Ignore system and dropped attributes in composite types (#43)

Author: elprans

asyncpg/introspection.py

@@ -20,6 +20,8 @@
             pg_attribute ia
             INNER JOIN pg_class c
                 ON (ia.attrelid = c.oid)
+        WHERE
+            ia.attnum > 0 AND NOT ia.attisdropped
         GROUP BY
             c.reltype
     ),

asyncpg/protocol/codecs/base.pyx

@@ -153,8 +153,14 @@ cdef class Codec:
 
             if received_elem_typ != elem_typ:
                 raise RuntimeError(
-                    'unexpected attribute data type: {}, expected {}'
-                        .format(received_elem_typ, elem_typ))
+                    'unexpected data type of composite type attribute {}: '
+                    '{!r}, expected {!r}'
+                        .format(
+                            i,
+                            TYPEMAP.get(received_elem_typ, received_elem_typ),
+                            TYPEMAP.get(elem_typ, elem_typ)
+                        )
+                )
 
             elem_len = hton.unpack_int32(buf.read(4))
             if elem_len == -1:

tests/test_codecs.py

@@ -867,12 +867,36 @@ async def test_composites_in_arrays(self):
             CREATE TABLE tab (d t[]);
         ''')
 
-        await self.con.execute(
-            'INSERT INTO tab (d) VALUES ($1)',
-            [('a', 1)])
+        try:
+            await self.con.execute(
+                'INSERT INTO tab (d) VALUES ($1)',
+                [('a', 1)])
+
+            r = await self.con.fetchval('''
+                SELECT d FROM tab
+            ''')
+
+            self.assertEqual(r, [('a', 1)])
+        finally:
+            await self.con.execute('''
+                DROP TABLE tab;
+                DROP TYPE t;
+            ''')
 
-        r = await self.con.fetchval('''
-            SELECT d FROM tab
+    async def test_table_as_composite(self):
+        await self.con.execute('''
+            CREATE TABLE tab (a text, b int);
+            INSERT INTO tab VALUES ('1', 1);
         ''')
 
-        self.assertEqual(r, [('a', 1)])
+        try:
+            r = await self.con.fetchrow('''
+                SELECT tab FROM tab
+            ''')
+
+            self.assertEqual(r, (('1', 1),))
+
+        finally:
+            await self.con.execute('''
+                DROP TABLE tab;
+            ''')