Bugzilla

As mentioned in https://bugzilla.mozilla.org/show_bug.cgi?id=1679012#c4 and following comments we would like to get rid of the cookie lifetime policy. While there used to be more options for cookie lifetime, the remaining one is "session".

For most users, the concept of "session" cookies is very hard to understand and so we try to make it a little more opaque by calling the option "Delete cookies and site data when Nightly is closed". Because this can already be done with sanitization preferences we effectively end up with two different ways in Firefox to clear cookies and site data on exit. The difference between is almost impossible to understand for anyone who is not a Firefox engineer.

In addition to usability concerns, having "in-memory-only" session cookie lifetime has meant adding ugly hacks and workarounds for most of our storage technologies for a long time now (or simply disabling them in that mode). We had already decided in the past to stop treating "session lifetime" as equivalent to "in-memory" to avoid these issues. At that point there's no real reason to have the concept of session lifetime anymore when all of it could be handled through sanitization.

The path forward here is to start removing UI that allows users to enable session lifetime and migrate all users with the pref set to sanitization prefs instead. If we do it right there should be few implications for the affected users except less site breakage :)

As mentioned in https://bugzilla.mozilla.org/show_bug.cgi?id=1679012#c4 and following comments we would like to get rid of the cookie lifetime policy. While there used to be more options for cookie lifetime, the remaining one is "session".

For most users, the concept of "session" cookies is very hard to understand and so we try to make it a little more opaque by calling the option "Delete cookies and site data when Nightly is closed". Because this can already be done with sanitization preferences we effectively end up with two different ways in Firefox to clear cookies and site data on exit. The difference between them is almost impossible to understand for anyone who is not a Firefox engineer.

In addition to usability concerns, having "in-memory-only" session cookie lifetime has meant adding ugly hacks and workarounds for most of our storage technologies for a long time now (or simply disabling them in that mode). We had already decided in the past to stop treating "session lifetime" as equivalent to "in-memory" to avoid these issues. At that point there's no real reason to have the concept of session lifetime anymore when all of it could be handled through sanitization.

The path forward here is to start removing UI that allows users to enable session lifetime and migrate all users with the pref set to sanitization prefs instead. If we do it right there should be few implications for the affected users except less site breakage :)