document should not be unloaded during same-document navigation

[kalenikaliaksandr]

the problem is reproducible with following steps:

1. navigable is navigated to a page
2. a script running on the page adds new session history entry by history.pushState()
3. traverse the history by a delta is called with delta = -1
4. apply the history step unloads a displayed document on step 14.11.1.1
5. activate history entry (step 14.11.1.3) fails because document in session history entry that should become active is unloaded although it is same-document navigation backwards.

it appears to be a bug that 14.11.1.1 step in apply the history step unloads document during same-document navigation.

[ADKaster]

@domenic this also occurs during fragment navigation via navigation.back() and navigation.forward(). In that case, we enter apply the history step through apply the push or replace history step via perform a navigation api traversal step 12.4

And it also happens from navigation.navigate(location.href + "#1", { history: "push" }) through navigate to a fragment step 18.1 which does the push or replace history step through finalize a same document navigation step 6.