`beforeRouteLeave` NOT called in a second time of `history.back()`

[vvenv]

when i call history.back() twice, the beforeRouteLeave hook will NOT be called in the 2nd time

Reproduction:
http://plato.crossjs.com/test.html#/

[fnlctrl]

Hi, thanks for filling this issue.
The behavior of clicking the browser back button is just as expected, because beforeRouteLeave doesn't stop the browser from changing the history record, but rather tries to fix it after the changes are made. This is to ensure consistent behavior for in-app redirections and direct url visits.

So, if you directly opened the link and click '/foo', there will be two history records: / and /foo(current). When the back button is clicked, browser changes the history to /, and beforeRouteLeave tries to fix it, so the browser history becomes /foo(current) and /foo. At this point the back button is disabled.

If you opened a blank page, then visit the link and click '/foo', you have 3 history records: blank page, / and /foo(current), so after the first click the history becomes blank page, /foo(current), /foo. This time the back button can be clicked again, and beforeRouteLeave isn't called since you're not leaving foo, but actually leaving of the app to blank page.

[vvenv]

Should guards keep the history records the same as current?

Like:

• Current history records is: blank page, / and /foo(current).
• Then click the back button.
• Current history records is: blank page, / and /foo(current).

[vvenv]

@fnlctrl
Use location.assign instead of location.replace in replaceHash() will resolve this issue.
https://github.com/vuejs/vue-router/blob/dev/src/history/hash.js#L90

Should we do it?

[fnlctrl]

@crossjs Sorry but location.assign cannot be used to replace location.replace because it will create a new record, instead of changing the current one in-place.