HTTP request handler: check sys.stderr != None before logging

[xiaolingbao]

BPO	44894

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-08-11.23:56:49.134>
labels = ['type-bug', 'library', '3.9']
title = 'HTTP request handler: check sys.stderr != None before logging'
updated_at = <Date 2021-08-13.23:02:22.093>
user = 'https://bugs.python.org/xiaolingbao'

bugs.python.org fields:

activity = <Date 2021-08-13.23:02:22.093>
actor = 'terry.reedy'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-08-11.23:56:49.134>
creator = 'xiaolingbao'
dependencies = []
files = []
hgrepos = []
issue_num = 44894
keywords = []
message_count = 2.0
messages = ['399423', '399470']
nosy_count = 1.0
nosy_names = ['xiaolingbao']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue44894'
versions = ['Python 3.9']

[xiaolingbao]

This is about HTTP server library (found on Windows with python 3.9, not sure other platforms).

In file Lib\http\server.py, we define:
class BaseHTTPRequestHandler(...):
def log_message(self, format, *args):
sys.stderr.write(...)

In certain cases, sys.stderr could be None and thus this function call will throw exception. My use case: I created an XMLRPC server (SimpleXMLRPCRequestHandler derives from BaseHTTPRequestHandler) within a Windows service. I guess with that combination, sys.stderr will be None. When this issue happens, the client got empty response and not much error log for debugging.

I can upload sample source code files if needed.

[xiaolingbao]

It looks https://bugs.python.org/issue43348 has the same root cause as this one. When running with pythonservice.exe or pythonw.exe, sys.stderr will be None and thus causing crash when logging messages (calling sys.stderr.write).