Autosave: Refreshing the screen after a published post autosave lands on error page

[aduth]

Describe the bug

An error page is shown if the user reloads the page after an autosave has occurred for a published post.

To Reproduce

1. Navigate to Posts > Add New
2. Enter a title and/or content
3. Publish the post
4. Change the title or content
5. Wait for autosave to occur
   • From what I can tell, there is no UI indication. It takes place after 10 seconds. You can watch your developer tools Network tab for the /autosaves POST request
6. Refresh the page
   • Accept the prompt

Expected behavior

I'm presented with the editor. Presumably in the state of the last publish, with a prompt for a newer autosave existing.

Suspected cause

Probably because the autosave is saved as a separate post entity, with its own ID, and since it's different and the post is published, we replace the browser's current URL with that of the autosave post ID, which isn't valid to be edited directly (only its parent).

gutenberg/editor/store/effects.js

Lines 215 to 221 in 26ebf42

	if ( get( window.history.state, [ 'id' ] ) !== post.id ) {
	window.history.replaceState(
	{ id: post.id },
	'Post ' + post.id,
	getPostEditUrl( post.id )
	);
	}

cc @adamsilverstein