[wp-trac] [WordPress Trac] #31695: Extra unclosed <p> tag before <script> breaking the_content()

[WordPress Trac]

#31695: Extra unclosed <p> tag before <script> breaking the_content()
--------------------------+-----------------------------
 Reporter:  vaurdan       |      Owner:
     Type:  defect (bug)  |     Status:  new
 Priority:  normal        |  Milestone:  Awaiting Review
Component:  Formatting    |    Version:  trunk
 Severity:  normal        |   Keywords:
  Focuses:                |
--------------------------+-----------------------------
 This bug was detected when trying to preview a post that had a Twitter
 oembed URL. There was no error on the log, and the previewed content was
 empty ( `the_content()` was printing an empty string ).

 After some debugging, I found that something was adding an extra `<p>` and
 never closing that tag, on the oembed returned markup, right before
 `<script>`:

 {{{
 <blockquote class="twitter-tweet" width="550">
 <p>Lisbon with #WordPressVIP @ Terreiro do Paço
 http://instagram.com/p/vGw5IchocB/ </p>
 <p>— Henrique Mouta (@vaurdan) <a
 href="https://twitter.com/vaurdan/status/530762912462557185">November 7,
 2014</a></blockquote>
 <p><script async src="//platform.twitter.com/widgets.js"
 charset="utf-8"></script></div>
 }}}

 I did some tracing and found out that it was `wpautop` fault. Even though
 `WP_oEmbed::_strip_newlines()` was successfully stripping the new lines
 from the returned oEmbed HTML, something was adding an extra newline
 before the `<script>` tag.

 {{{
 $allblocks =
 '(?:table|thead|tfoot|caption|col|colgroup|tbody|tr|td|th|div|dl|dd|dt|ul|ol|li|pre|form|map|area|blockquote|address|math|style|p|h[1-6]|hr|fieldset|legend|section|article|aside|hgroup|header|footer|nav|figure|details|menu|summary)';
 $pee = preg_replace('!(<' . $allblocks . '[^>]*>)!', "\n$1", $pee);
 $pee = preg_replace('!(</' . $allblocks . '>)!', "$1\n\n", $pee);
 }}}

 And that was happening because `<blockquote>` is on the `$allblocks`,
 making a newline between `blockquote` and `script`.

 To fix this, I used the same logic that `wpautop` uses for `<object>`,
 `<option>`, `<source>`, and `<track>`:  have no `<p>` or `<br/>` around
 the `<script>` tag:

 {{{
 if ( strpos( $pee, '<script' ) !== false ) {
         // no P/BR around script
         $pee = preg_replace( '|\s*<script|', '<script', $pee );
         $pee = preg_replace( '|</script>\s*|', '</script>', $pee );
 }
 }}}

 Now the oembed is fully functional and doesn't have that unclosed `<p>`
 tag:

 {{{
 <blockquote class="twitter-tweet" width="550">
 <p>Lisbon with #WordPressVIP @ Terreiro do Paço
 http://instagram.com/p/vGw5IchocB/ </p>
 <p>— Henrique Mouta (@vaurdan) <a
 href="https://twitter.com/vaurdan/status/530762912462557185">November 7,
 2014</a></blockquote><script async src="//platform.twitter.com/widgets.js"
 charset="utf-8"></script></div>
 }}}

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Ticket URL: <https://core.trac.wordpress.org/ticket/31695>
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