+++ This bug was initially created as a clone of Bug #8790 +++

I have discovered a number of bugs in the $wgUseMetadataEdit code:

• "show changes" on the edit page does not include the metadata

• metadata edits can be lost or misordered during section edits
  • the current code will simply stuff the new/edited metadata into the end of the section being edited, while leaving any existing metadata at the end of the article.

• the parser that extracts metadata appears to have a condition that can cause the loss of content from previous revisions.
  • i did not actually experience this bug, but in trying to understand how the parser works, i discovered that it sometimes fails to un-explode the content, which could in theory replace text with "Array" in the articles. Look for the "$y = implode("]]", $y)" on line 70 of my patch.

• metadata ordering can change between normal edits, which makes history diffs messy.
  1. edit the page. add a new whitelist metadata field to the normal textbox. save the page. Note in the source of the new revision that your metadata is still in the middle of the article content.
  2. edit the page again. add some new content in the normal textbox. save the page. Note that the source of the new revision now has the metadata from step 1 located at the end of the text, rather than in the middle of it.

I believe that I have fixed these bugs, and I will attach the patch in
a moment. The patch also includes two new hooks, which allow
an extension to replace both the metadata parser and the metadata
textbox on the EditPage. I believe that this patch will have zero
impact on any installations that are not using $wgUseMetaDataEdit.

Version: unspecified
Severity: normal