Do not prefix wp_title() with spaces if $sep is empty

[SergeyBiryukov]

1. Add wp_title('') to header.php.
2. Notice two spaces before the title:

   <title>  Hello World</title>
   

This was previously brought up in #7114, but the fix suggested there wasn't backward compatible.

[nacin]

Wondering if one space might still be expected by themes. For example, if bloginfo('name') is used before wp_title();

[SergeyBiryukov]

#22653 was marked as a duplicate.

[chipbennett]

Replying to nacin:

Wondering if one space might still be expected by themes. For example, if bloginfo('name') is used before wp_title();

Themes should not be putting anything other than <?php wp_title(); ?> inside of the HTML <title></title> tags. Adding bloginfo( 'name' ) should be done via wp_title filter, even in Themes. Note that this is enforced in the Theme Review guidelines, so if that use case the only impediment, I would recommend not holding up this patch because of it.

[SergeyBiryukov]

Related: #31956

[wonderboymusic]

19674.diff​ is a refresh after 4.4

[obenland]

Hm, I'm not sure how much of an issue this really is in wp_document_title(). If the separator happens to be empty, the double space is only inserted between title parts, never before or after. This seems to be more of an issue with wp_title()'s $prefix content.

Does this need fixing at all? It's not something that is visible in browser tabs, is it?