can't navigate to initial state using dojo.back

[coldwind]

After several dojo.back.attToHistory() with unique changeUrl value you can't back to initial state (FF3).

To reproduce this issue open: ​http://archive.dojotoolkit.org/nightly/dojotoolkit/dojo/tests/back.html

and then click "Link 1", "Link 3" and again "Link 1". After that navigation with browser's "Back" button (only "Back", i.e. previous page) shows:

Back/Forward? Info:
BACK for State Data: This is data for link 3
FORWARD for State Data: This is data for link 1

If I chain only "Link 1", "Link 3" and "Link 4" then it will show:

Back/Forward? Info:
BACK for State Data: This is data for link 3
BACK for State Data: This is data for link 1
BACK for State Data: This is the initial state (page first loaded)

[Ben Lowery]

Sadly we have no way to deal with this case. What happens is this: history is stored as an array (two actually, but it doesn't matter). each element in the array has a urlHash associated with it. when we pick up a hash change, we look at the hash before and after the current hash to see if it matches the new browser hash. In the case illustrated above, we end up in a state where we have the same hash before and after the current hash, so we don't really know whether to go forward or backward.

One way to solve this is to use unique hashes. In the case above, we'd stick a timestamp after the named hash value. Then things work as you would expect with history.

Back implementation tend to try to serve two cases: the case where you just want to react to a hash change, and the case where you truly want to record the full back/forward motion the user takes through the site. Our test illustrates the first, and sadly not the second.