Error calling BaseHTTPRequestHandler.end_headers()

Bug report

Bug description:

If a call is made to BaseHTTPRequestHandler.end_headers() but no headers or response have been queued, an exception is raised exposing implementation details.

    class request_handler(BaseHTTPRequestHandler):
        def do_GET(self):
            self.end_headers()

Actual result

AttributeError("'request_handler' object has no attribute '_headers_buffer'")

Expected result:

pass

flush_headers has a guard to check if the buffer has been allocated which is missing from end_headers

if hasattr(self, '_headers_buffer'):

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-131718

首先定位 CPython 的 BaseHTTPRequestHandler.end_headers() 並將其處理方式與 flush_headers() 進行比較，尤其要檢查報告中描述的 _headers_buffer 保護。完成的標準是：在沒有排隊的標頭或 response 的情況下呼叫 end_headers()，能夠完成且不會暴露 AttributeError；開始前請檢查關聯的 PR gh-131718。