Bug report

Currently the following is False

from urllib.request import Request, urlopen

len(urlopen(Request("http://google.com", method="HEAD")).read()) == 0  # False

But this is True

len(urlopen(Request("http://www.google.com", method="HEAD")).read()) == 0 # True

This is because http://google.com redirects with 302 to http://www.google.com.

This means that checking for existence of some file by URL will actually download the file when the URL responds with a redirect. This makes no sense. Also the HTTP spec says nothing about changing HEAD requests into GET requests; it just says that everything but GET and HEAD requests should require user interaction on redirect, which Python violates, but there's a comment on that explaining it's an active choice to violate the spec there.

To me it seems like this is an oversight. Note that curl -LI http://google.com also sticks to HEAD requests.

Linked PRs

• gh-99730: HEAD should remain HEAD request on redirect #99731