[PR #7651/45f98b7d backport][3.9] Fix BadStatusLine message (#7667)

**This is a backport of PR #7651 as merged into master
(45f98b7).**

CHANGES/7651.bugfix

@@ -0,0 +1 @@
+Fixed display of ``BadStatusLine`` messages from ``llhttp`` -- by :user:`Dreamsorcerer`

aiohttp/_http_parser.pyx

@@ -2,7 +2,6 @@
 #
 # Based on https://github.com/MagicStack/httptools
 #
-from __future__ import absolute_import, print_function
 
 from cpython cimport (
     Py_buffer,
@@ -813,7 +812,9 @@ cdef parser_error_from_errno(cparser.llhttp_t* parser, data, pointer):
     cdef cparser.llhttp_errno_t errno = cparser.llhttp_get_errno(parser)
     cdef bytes desc = cparser.llhttp_get_error_reason(parser)
 
-    if errno in (cparser.HPE_CB_MESSAGE_BEGIN,
+    err_msg = "{}:\n\n  {!r}\n  {}".format(desc.decode("latin-1"), data, pointer)
+
+    if errno in {cparser.HPE_CB_MESSAGE_BEGIN,
                  cparser.HPE_CB_HEADERS_COMPLETE,
                  cparser.HPE_CB_MESSAGE_COMPLETE,
                  cparser.HPE_CB_CHUNK_HEADER,
@@ -823,22 +824,13 @@ cdef parser_error_from_errno(cparser.llhttp_t* parser, data, pointer):
                  cparser.HPE_INVALID_CONTENT_LENGTH,
                  cparser.HPE_INVALID_CHUNK_SIZE,
                  cparser.HPE_INVALID_EOF_STATE,
-                 cparser.HPE_INVALID_TRANSFER_ENCODING):
-        cls = BadHttpMessage
-
-    elif errno == cparser.HPE_INVALID_STATUS:
-        cls = BadStatusLine
-
-    elif errno == cparser.HPE_INVALID_METHOD:
-        cls = BadStatusLine
-
-    elif errno == cparser.HPE_INVALID_VERSION:
-        cls = BadStatusLine
-
+                 cparser.HPE_INVALID_TRANSFER_ENCODING}:
+        return BadHttpMessage(err_msg)
+    elif errno in {cparser.HPE_INVALID_STATUS,
+                   cparser.HPE_INVALID_METHOD,
+                   cparser.HPE_INVALID_VERSION}:
+        return BadStatusLine(error=err_msg)
     elif errno == cparser.HPE_INVALID_URL:
-        cls = InvalidURLError
-
-    else:
-        cls = BadHttpMessage
+        return InvalidURLError(err_msg)
 
-    return cls("{}:\n\n  {!r}\n  {}".format(desc.decode("latin-1"), data, pointer))
+    return BadHttpMessage(err_msg)

aiohttp/http_exceptions.py

@@ -95,10 +95,10 @@ def __init__(self, hdr: Union[bytes, str]) -> None:
 
 
 class BadStatusLine(BadHttpMessage):
-    def __init__(self, line: str = "") -> None:
+    def __init__(self, line: str = "", error: Optional[str] = None) -> None:
         if not isinstance(line, str):
             line = repr(line)
-        super().__init__(f"Bad status line {line!r}")
+        super().__init__(error or f"Bad status line {line!r}")
         self.args = (line,)
         self.line = line
 

tests/test_http_parser.py

@@ -656,8 +656,10 @@ def test_http_request_parser(parser) -> None:
 
 def test_http_request_bad_status_line(parser) -> None:
     text = b"getpath \r\n\r\n"
-    with pytest.raises(http_exceptions.BadStatusLine):
+    with pytest.raises(http_exceptions.BadStatusLine) as exc_info:
         parser.feed_data(text)
+    # Check for accidentally escaped message.
+    assert r"\n" not in exc_info.value.message
 
 
 def test_http_request_upgrade(parser) -> None: