Warn if package index gets unexpected Content-Type

[deveshks]

Fixes and closes #6754

[sbidoul]

I note all error reports in this area are debug level. Does it make sense to change only one of them? On the contrary, would it make sense to change all of them?

[deveshks]

I note all error reports in this area are debug level. Does it make sense to change only one of them? On the contrary, would it make sense to change all of them?

I think we can change https://github.com/pypa/pip/blob/master/src/pip/_internal/index/collector.py#L437 and https://github.com/pypa/pip/blob/master/src/pip/_internal/index/collector.py#L453 , both to logger.warning, since they both look like user errors in providing arguments to pip command line, and can be potentially helpful to show it to them

Perhaps: https://github.com/pypa/pip/blob/master/src/pip/_internal/index/collector.py#L411 as well, but this lies outside _get_html_page

[deveshks]

As per #8083 (comment) , can I extend the scope of this issue, as well as the associated PR to include the remaining two logger.debug messages which actually contain an error to logger.warning, or should I do that perhaps as part of another PR (I am more in favor of handling this as part of another PR)

[pfmoore]

One minor wording nit

[pfmoore]

I'm happy to have changing the other messages' level be in a separate PR. I'm not entirely sure that the other messages even should be changed to warnings - IMO that should be discussed and decided on a case by case basis, so a separate PR seems correct.

[deveshks]

I'm happy to have changing the other messages' level be in a separate PR. I'm not entirely sure that the other messages even should be changed to warnings - IMO that should be discussed and decided on a case by case basis, so a separate PR seems correct.

I have gone ahead and create an issue to discuss this #8128 , and get some agreement before creating a PR for the same

[deveshks]

If there are no more changes necessary to be done in this PR, may I get this merged?