remove TODO, as Cache-Control: no-cache is the correct behavior

src/pip/_internal/network/lazy_wheel.py

@@ -156,6 +156,14 @@ def __next__(self) -> bytes:
 _DEFAULT_INITIAL_FETCH = 1_000_000
 
 
+# The requests we perform in this file are intentionally small, and we don't want to
+# guess at how the server will interpret caching directives for range requests (we
+# especially don't want the server to return 200 OK with the entire file contents).
+# TODO: consider If-Match (etag) and handling 304 File Modified, here or in the
+#       unpack_url() method.
+_UNCACHED_HEADERS = {**HEADERS, 'Cache-Control': 'no-cache'}
+
+
 class LazyHTTPFile(ReadOnlyIOWrapper):
     """File-like object mapped to a ZIP file over HTTP.
 
@@ -231,13 +239,13 @@ def __exit__(self, *exc: Any) -> None:
 
     def _content_length_from_head(self) -> int:
         self._request_count += 1
-        head = self._session.head(self._url, headers=HEADERS)
+        head = self._session.head(self._url, headers=_UNCACHED_HEADERS)
         head.raise_for_status()
         assert head.status_code == codes.ok
         accepted_range = head.headers.get("Accept-Ranges", None)
         if accepted_range != "bytes":
             raise HTTPRangeRequestUnsupported(
-                f"server does not support byte ranges: header was {accepted_range}"
+                f"server does not support byte ranges: header was '{accepted_range}'"
             )
         return int(head.headers["Content-Length"])
 
@@ -249,14 +257,10 @@ def _parse_full_length_from_content_range(arg: str) -> int:
         return int(m.group(1))
 
     def _try_initial_chunk_request(self, initial_chunk_size: int) -> tuple[int, bytes]:
-        headers = HEADERS.copy()
+        headers = _UNCACHED_HEADERS.copy()
         # Perform a negative range index, which is not supported by some servers.
         headers["Range"] = f"bytes=-{initial_chunk_size}"
         logger.debug("initial bytes request: %s", headers["Range"])
-        # TODO: Get range requests to be correctly cached
-        headers["Cache-Control"] = "no-cache"
-        # TODO: If-Match (etag) to detect file changed during fetch would be a
-        # good addition to HEADERS
 
         self._request_count += 1
         tail = self._session.get(self._url, headers=headers)
@@ -339,13 +343,9 @@ def _stay(self) -> Iterator[None]:
     def _stream_response(self, start: int, end: int) -> Response:
         """Return streaming HTTP response to a range request from start to end."""
         # https://www.rfc-editor.org/rfc/rfc9110#field.content-range
-        headers = HEADERS.copy()
+        headers = _UNCACHED_HEADERS.copy()
         headers["Range"] = f"bytes={start}-{end}"
         logger.debug("streamed bytes request: %s", headers["Range"])
-        # TODO: Get range requests to be correctly cached
-        headers["Cache-Control"] = "no-cache"
-        # TODO: If-Match (etag) to detect file changed during fetch would be a
-        # good addition to HEADERS
         self._request_count += 1
         response = self._session.get(self._url, headers=headers, stream=True)
         response.raise_for_status()