[syahra712]

A request with the header Range: bytes=- makes WebOb raise instead of ignoring the malformed header:

>>> from webob import Request, Response
>>> req = Request.blank("/", headers={"Range": "bytes=-"})
>>> req.range
ValueError: invalid literal for int() with base 10: ''
>>> req.get_response(Response(body=b"hello", conditional_response=True))
ValueError: invalid literal for int() with base 10: ''

Because the header comes from the client, any app that uses conditional_response=True (for example static file serving) returns a 500 for that request.

Cause: _rx_range is bytes *= *(\d*) *- *(\d*), so bytes=- matches with both groups empty. Range.parse then takes the suffix branch and calls int(""). Other malformed values already return None (the documented "may return None if header is invalid").

Fix: return None when both positions are empty. The header is then ignored, as for other invalid ranges.

Tests:

• Parse cases in test_range_parse.
• A conditional-response test that expects a 200 with the full body.

Both fail without the change. The full suite passes (2399 passed), and black and isort are clean. I also added a Bugfix entry to CHANGES.txt.

This doesn't overlap with #502, which changes range_for_length for oversized suffix ranges.

AI-assisted (Claude): I used it to help read the code and draft the test. I reviewed and ran everything myself.