text encoding of composite types error with schema and table name.

• asyncpg version: 0.23.0
• PostgreSQL version: 10.13
• Do you use a PostgreSQL SaaS? If so, which? Can you reproduce
  the issue with a local PostgreSQL install?: No. I ran PG on local machine.
• Python version: 3.8.2
• Platform: MacOs catalina 10.15.7
• Do you use pgbouncer?: No
• Did you install asyncpg with pip?: Yes
• If you built asyncpg locally, which version of Cython did you use?: No
• Can the issue be reproduced under both asyncio and
  uvloop?: Not tried

Hello!

I have table with ltree column:

create table product
(
    product_id    varchar(18)                                    not null
        constraint product_pkey
            primary key,
    category_path ltree
);

And trying execute this SQL query:

    insert into product
    (product_id, category_path)
    (select  r.product_id, r.category_path from unnest($1::product[]) as r)

Args:

[[{'category_path': 'A.B', 'product_id': '3912331'}]]

And i get this error:

File "/venv/lib/python3.8/site-packages/asyncpg/pool.py", line 530, in execute
    return await con.execute(query, *args, timeout=timeout)
  File "/venv/lib/python3.8/site-packages/asyncpg/connection.py", line 299, in execute
    _, status, _ = await self._execute(
  File "/venv/lib/python3.8/site-packages/asyncpg/connection.py", line 1623, in _execute
    result, _ = await self.__execute(
  File "/venv/lib/python3.8/site-packages/asyncpg/connection.py", line 1648, in __execute
    return await self._do_execute(
  File "/venv/lib/python3.8/site-packages/asyncpg/connection.py", line 1675, in _do_execute
    stmt = await self._get_statement(
  File "/venv/lib/python3.8/site-packages/asyncpg/connection.py", line 392, in _get_statement
    settings.register_data_types(types)
  File "asyncpg/protocol/settings.pyx", line 35, in asyncpg.protocol.protocol.ConnectionSettings.register_data_types
  File "asyncpg/protocol/settings.pyx", line 36, in asyncpg.protocol.protocol.ConnectionSettings.register_data_types
  File "asyncpg/protocol/codecs/base.pyx", line 506, in asyncpg.protocol.protocol.DataCodecConfig.add_types
  File "asyncpg/protocol/codecs/base.pyx", line 371, in asyncpg.protocol.protocol.Codec.new_composite_codec
  File "asyncpg/protocol/codecs/base.pyx", line 76, in asyncpg.protocol.protocol.Codec.init
asyncpg.exceptions._base.UnsupportedClientFeatureError: cannot decode type "public"."product": text encoding of composite types is not supported

But "public"."product" -- it's schema and table name.

If i create new table with category_path = text instead ltree, all ok.

Beginne damit, die Abfrage mit der ltree-Spalte und dem zusammengesetzten Produkttyp zu reproduzieren. Untersuche anschließend asyncpg/protocol/settings.pyx und asyncpg/protocol/codecs/base.pyx, die im Traceback erscheinen. Verfolge die Registrierung des zusammengesetzten Typs und überprüfe, dass das Verhalten für diesen Fall korrigiert ist, ohne die bestehende Behandlung zusammengesetzter Typen zu beeinträchtigen.