"AttributeError: 'NoneType' object has no attribute 'decode'" when executing empty script

Start with asyncpg/connection.py at Connection.execute and follow the protocol query path shown in asyncpg/protocol/protocol.pyx, especially _on_result__simple_query. Reproduce the comment-only query, then add or update coverage so it completes successfully without the NoneType decode error and preserves normal results for nonempty queries.

Wouldn't it be natural that executing a script with only comments is a no-op returning OK?
Such that for example commenting out the contents of a migration script while developing runs the script as a no-op.

Instead what happens when running this:

import os
import asyncpg
import asyncio

async def main():
    conn = await asyncpg.connect(os.environ["DATABASE_URI"])
    async with conn.transaction():
        await conn.execute("-- hello")

if __name__ == "__main__":
    asyncio.run(main())

Is this:

Traceback (most recent call last):
  File "/home/msa/dev/sandbox/pgtesting/hello.py", line 13, in <module>
    asyncio.run(main())
    ~~~~~~~~~~~^^^^^^^^
  File "/home/msa/.local/share/uv/python/cpython-3.13.0-linux-x86_64-gnu/lib/python3.13/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ~~~~~~~~~~^^^^^^
  File "/home/msa/.local/share/uv/python/cpython-3.13.0-linux-x86_64-gnu/lib/python3.13/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^
  File "/home/msa/.local/share/uv/python/cpython-3.13.0-linux-x86_64-gnu/lib/python3.13/asyncio/base_events.py", line 721, in run_until_complete
    return future.result()
           ~~~~~~~~~~~~~^^
  File "/home/msa/dev/sandbox/pgtesting/hello.py", line 9, in main
    await conn.execute("-- hello")
  File "/home/msa/dev/sandbox/pgtesting/.venv/lib/python3.13/site-packages/asyncpg/connection.py", line 349, in execute
    result = await self._protocol.query(query, timeout)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "asyncpg/protocol/protocol.pyx", line 375, in query
  File "asyncpg/protocol/protocol.pyx", line 888, in asyncpg.protocol.protocol.BaseProtocol._dispatch_result
  File "asyncpg/protocol/protocol.pyx", line 815, in asyncpg.protocol.protocol.BaseProtocol._on_result__simple_query
AttributeError: 'NoneType' object has no attribute 'decode'

Setup is just

mkdir hello
cd hello
uv init .
uv add asyncpg
export DATABUTTON_URI="something"
uv run hello.py # above example