history.replaceState/location.replace incorrectly adds new entries to global history in Safari

• Component: Page Loading
• Status: NEW ---

[Jason Davies]

The purpose of history.replaceState is to *modify* the current history entry.  This works in the context of using the back button.

However, it always seems to add *new* history entries, in the context of the History menu item (and "Show History" page).

This causes a huge number of history entries for pages that update the URL frequently, e.g. zoom/pan of maps where the current zoom and position are encoded in the URL.

A good example of this in the wild is http://polymaps.org/ - e.g. http://polymaps.org/ex/midnight-commander.html - note that Polymaps actually uses location.replace internally with the same problem, though using history.replaceState doesn't fix it.

[Jason Davies]

Interestingly, Chrome appears to have the same behaviour for history.replaceState (adding new entries to the history page) - but not for location.replace.

[Brady Eidson]

The specs declare when the browser engine has to do with the session history, which is what is represented by the back button. And WebKit handles that correctly.

I don't believe any spec defines what browsers have to do with their global history collections, as that's outside the scope of the engine.

So I think you're reporting a Safari bug, as Safari decides what entires to show in its history menu. And Safari is not WebKit.