urllib.request.urlopen(data_uri).file are closed automatically when the response is not hold by a variable

Bug report

Opening a data uri with urllib.request.urlopen and read it directly will result in I/O operation on closed file..

Errored example:

from urllib.request import urlopen

url = 'data:text/plain,hello world'
print(urlopen(url).file.read())

"""
Output:

Traceback (most recent call last):
  File "/home/maple3142/tmp/xa.py", line 4, in <module>
    print(urlopen(url).file.read())
ValueError: I/O operation on closed file.
"""

Normal example:

from urllib.request import urlopen

url = 'data:text/plain,hello world'
resp = urlopen(url)
print(resp.file.read())

"""
Output:

b'hello world'
"""

Your environment

• CPython versions tested on: 3.8.11, 3.10.4
• Operating system and architecture: Arch Linux on WSL2 on Windows 10 x64

先重現 urllib.request.urlopen 的兩個範例，然後檢查該進入點背後的 data-URI 處理。完成標準是直接鏈式呼叫 .file.read() 能夠正常運作且不會出現檔案已關閉錯誤，同時現有的儲存回應範例仍然正確，並為此行為加入回歸測試。