lazy-wheel: improve handling of servers that tell us that they support range requests but do not respect them

src/poetry/inspection/lazy_wheel.py

@@ -49,6 +49,11 @@ class HTTPRangeRequestUnsupported(LazyWheelUnsupportedError):
     """Raised when the remote server appears unable to support byte ranges."""
 
 
+class HTTPRangeRequestNotRespected(LazyWheelUnsupportedError):
+    """Raised when the remote server tells us that it supports byte ranges
+    but does not respect a respective request."""
+
+
 class UnsupportedWheel(LazyWheelUnsupportedError):
     """Unsupported wheel."""
 
@@ -429,7 +434,12 @@ def _stream_response(self, start: int, end: int) -> Response:
         self._request_count += 1
         response = self._session.get(self._url, headers=headers, stream=True)
         response.raise_for_status()
-        assert int(response.headers["Content-Length"]) == (end - start + 1)
+        if int(response.headers["Content-Length"]) != (end - start + 1):
+            raise HTTPRangeRequestNotRespected(
+                f"server did not respect byte range request: "
+                f"requested {end - start + 1} bytes, got "
+                f"{response.headers['Content-Length']} bytes"
+            )
         return response
 
     def _fetch_content_range(self, start: int, end: int) -> Iterator[bytes]:

tests/inspection/test_lazy_wheel.py

@@ -14,6 +14,7 @@
 
 from requests import codes
 
+from poetry.inspection.lazy_wheel import HTTPRangeRequestNotRespected
 from poetry.inspection.lazy_wheel import HTTPRangeRequestUnsupported
 from poetry.inspection.lazy_wheel import InvalidWheel
 from poetry.inspection.lazy_wheel import LazyWheelUnsupportedError
@@ -38,6 +39,7 @@ def __call__(
             *,
             accept_ranges: str | None = "bytes",
             negative_offset_error: tuple[int, bytes] | None = None,
+            ignore_accept_ranges: bool = False,
         ) -> HTTPrettyRequestCallback: ...
 
     class AssertMetadataFromWheelUrl(Protocol):
@@ -113,6 +115,7 @@ def _factory(
         *,
         accept_ranges: str | None = "bytes",
         negative_offset_error: tuple[int, bytes] | None = None,
+        ignore_accept_ranges: bool = False,
     ) -> HTTPrettyRequestCallback:
         def handle_request(
             request: HTTPrettyRequest, uri: str, response_headers: dict[str, Any]
@@ -156,7 +159,7 @@ def handle_request(
                         response_headers,
                         negative_offset_error[1],
                     )
-            if accept_ranges == "bytes" and rng:
+            if accept_ranges == "bytes" and rng and not ignore_accept_ranges:
                 return build_partial_response(
                     rng,
                     wheel_bytes,
@@ -404,6 +407,31 @@ def test_metadata_from_wheel_url_range_requests_not_supported_two_requests(
     assert latest_requests[1].method == "HEAD"
 
 
+def test_metadata_from_wheel_url_range_requests_supported_but_not_respected(
+    http: type[httpretty.httpretty],
+    handle_request_factory: RequestCallbackFactory,
+) -> None:
+    domain = "range-requests-not-respected.com"
+    uri_regex = re.compile(f"^https://{domain}/.*$")
+    request_callback = handle_request_factory(
+        negative_offset_error=(codes.method_not_allowed, b"Method not allowed"),
+        ignore_accept_ranges=True,
+    )
+    http.register_uri(http.GET, uri_regex, body=request_callback)
+    http.register_uri(http.HEAD, uri_regex, body=request_callback)
+
+    url = f"https://{domain}/poetry_core-1.5.0-py3-none-any.whl"
+
+    with pytest.raises(HTTPRangeRequestNotRespected):
+        metadata_from_wheel_url("poetry-core", url, requests.Session())
+
+    latest_requests = http.latest_requests()
+    assert len(latest_requests) == 3
+    assert latest_requests[0].method == "GET"
+    assert latest_requests[1].method == "HEAD"
+    assert latest_requests[2].method == "GET"
+
+
 def test_metadata_from_wheel_url_invalid_wheel(
     http: type[httpretty.httpretty],
     handle_request_factory: RequestCallbackFactory,