Posting comment on draft post just gives a white page

[floriansw]

If a blog post is in state "draft" and it is viewed as a preview on the blog, the comment box is already there. If the user then enters a comment and clicks "Submit", the user get's a white page only. This is because of the returned error does not contain any message:

object(WP_Error)#8374 (2) { ["errors"]=> array(1) { ["comment_on_draft"]=> array(1) { [0]=> string(0) "" } } ["error_data"]=> array(0) { } }

and the wp-comment-post.php script simply exits in this case:
​https://github.com/WordPress/WordPress/blob/master/wp-comments-post.php#L26-L33

Ideally, WP should give a proper error message, which indicates, why the comment could not be saved.

[johnbillion]

Thanks for the report, @floriansw.

This was actually fixed in WordPress 4.8, ​which will be released in June. You can ​try the beta yourself if you want to help test it.

See #39650