Add builtin varchar array codec

asyncpg/protocol/codecs/array.pyx

@@ -858,8 +858,17 @@ cdef arraytext_decode(ConnectionSettings settings, FRBuffer *buf):
     return array_decode(settings, buf, <decode_func_ex>&text_decode_ex, NULL)
 
 
+cdef arrayvarchar_encode(ConnectionSettings settings, WriteBuffer buf, items):
+    array_encode(settings, buf, items, VARCHAROID,
+                 <encode_func_ex>&text_encode_ex, NULL)
+
+
+cdef arrayvarchar_decode(ConnectionSettings settings, FRBuffer *buf):
+    return array_decode(settings, buf, <decode_func_ex>&text_decode_ex, NULL)
+
+
 cdef init_array_codecs():
-    # oid[] and text[] are registered as core codecs
+    # oid[], text[], and varchar[] are registered as core codecs
     # to make type introspection query work
     #
     register_core_codec(_OIDOID,
@@ -872,4 +881,9 @@ cdef init_array_codecs():
                         <decode_func>&arraytext_decode,
                         PG_FORMAT_BINARY)
 
+    register_core_codec(_VARCHAROID,
+                        <encode_func>&arrayvarchar_encode,
+                        <decode_func>&arrayvarchar_decode,
+                        PG_FORMAT_BINARY)
+
 init_array_codecs()

asyncpg/protocol/pgtypes.pxi

@@ -51,6 +51,7 @@ DEF MONEYOID = 790
 DEF MACADDROID = 829
 DEF INETOID = 869
 DEF _TEXTOID = 1009
+DEF _VARCHAROID = 1015
 DEF _OIDOID = 1028
 DEF ACLITEMOID = 1033
 DEF BPCHAROID = 1042
@@ -113,7 +114,7 @@ DEF ANYCOMPATIBLEARRAYOID = 5078
 DEF ANYCOMPATIBLENONARRAYOID = 5079
 DEF ANYCOMPATIBLERANGEOID = 5080
 
-ARRAY_TYPES = {_TEXTOID, _OIDOID}
+ARRAY_TYPES = {_TEXTOID, _VARCHAROID, _OIDOID}
 
 BUILTIN_TYPE_OID_MAP = {
     ABSTIMEOID: 'abstime',
@@ -215,7 +216,8 @@ BUILTIN_TYPE_OID_MAP = {
     XIDOID: 'xid',
     XMLOID: 'xml',
     _OIDOID: 'oid[]',
-    _TEXTOID: 'text[]'
+    _TEXTOID: 'text[]',
+    _VARCHAROID: 'varchar[]'
 }
 
 BUILTIN_TYPE_NAME_MAP = {v: k for k, v in BUILTIN_TYPE_OID_MAP.items()}

tests/test_introspection.py

@@ -25,6 +25,15 @@ async def _introspect_types(self, *args, **kwargs):
         return await super()._introspect_types(*args, **kwargs)
 
 
+class CountingIntrospectionConnection(apg_con.Connection):
+    """Connection class to assert when type introspection is skipped."""
+    introspect_count = 0
+
+    async def _introspect_types(self, *args, **kwargs):
+        self.introspect_count += 1
+        return await super()._introspect_types(*args, **kwargs)
+
+
 class TestIntrospection(tb.ConnectedTestCase):
     @classmethod
     def setUpClass(cls):
@@ -78,6 +87,29 @@ async def test_introspection_on_large_db(self):
         with self.assertRunUnder(MAX_RUNTIME):
             await self.con.fetchval('SELECT $1::int[]', [1, 2])
 
+    async def test_varchar_array_does_not_introspect(self):
+        conn = await self.connect(
+            connection_class=CountingIntrospectionConnection)
+        try:
+            cases = [
+                ['a', 'b'],
+                [None, 'b'],
+                [],
+                [['a', 'b'], ['c', 'd']],
+            ]
+
+            for case in cases:
+                result = await conn.fetchval('SELECT $1::varchar[]', case)
+                self.assertEqual(result, case)
+
+            result = await conn.fetchval(
+                "SELECT ARRAY['a', 'b']::varchar[]")
+            self.assertEqual(result, ['a', 'b'])
+
+            self.assertEqual(conn.introspect_count, 0)
+        finally:
+            await conn.close()
+
     @tb.with_connection_options(statement_cache_size=0)
     async def test_introspection_no_stmt_cache_01(self):
         old_uid = apg_con._uid

tools/generate_type_map.py

@@ -16,7 +16,7 @@
 # Array types with builtin codecs, necessary for codec
 # bootstrap to work
 #
-_BUILTIN_ARRAYS = ('_text', '_oid')
+_BUILTIN_ARRAYS = ('_text', '_varchar', '_oid')
 
 _INVALIDOID = 0