Post Editor: BrowserURL should be resilient to post save failure

[aduth]

Related: #7122 (specifically #7122 (comment) )

Currently, if a save request fails for a post where the request explicitly updates the post status, the BrowserURL component introduced in #7122 will not revert the URL back to post-new.php if the post was an auto-draft at the time of initiating the save.

Steps to reproduce:

1. Navigate to Posts > Add New
2. Go offline (e.g. Chrome "Offline" preset in Developer Tools)
3. Enter a title
4. Publish the post

Expected result:

The post is optimistically assumed to update, thus it's reasonable for the URL to change, but once the save fails, it should revert back to the URL which had existed prior to the save being initiated (i.e. post-new.php).

Actual result:

The URL lingers in its optimistic state.

Fortunately, from what has been tested, it is perfectly okay for post-new.php to be treated as equivalent to post.php?id=XYZ&action=edit where XYZ is the post ID for an auto-draft post, so no breakage occurs.

[aduth]

Fortunately, from what has been tested, it is perfectly okay for post-new.php to be treated as equivalent to post.php?id=XYZ&action=edit where XYZ is the post ID for an auto-draft post, so no breakage occurs.

@danielbachhuber Based on your comment from Slack today, might I expect you'd propose we consider treating this as the default behavior anyways?

[danielbachhuber]

might I expect you'd propose we consider treating this as the default behavior anyways?

Yes, I think this is a reasonable assumption, respecting any future discoveries otherwise.

[danielbachhuber]

Related #3702 (comment)

[tofumatt]

Sounds like #6322 is related too.

[nerrad]

Triage review agrees that this seems to be expected behaviour. See discussion context on Slack (requires signup)