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$wgUseMetaDataEdit extension-ification
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Author: marcus

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: 1.9.x
Severity: enhancement



Event Timeline

bzimport raised the priority of this task from to Medium.Nov 21 2014, 9:33 PM
bzimport set Reference to bz8790.

marcus wrote:

Patch for metadataedit bugs

attachment mediawiki-1.9.0-metaedit.patch ignored as obsolete

marcus wrote:

hashar on freenode MediaWiki-General made some comments about removing this code from
the mediawiki core entirely, and moving it into an extension. I suppose this
makes sense, since I can't imagine that any major mediawiki installations are
using this anyway, given the bugs in it.

If this is preferable, I can put together a patch that removes all of this code
and replaces it with a handful of hooks, and then create a basic extension that
provides the same functionality.

This would actually be preferable to me, as I am already building another
extension that provides more advanced metadata editing functionality, and this
would greatly improve the modularity/integration of that extension as well.

marcus wrote:

second rev of patch for metaedit bugs

There was still a section editing bug in the previous patch.


marcus wrote:

per a freenode discussion with brion, I will prepare a patch that removes all
metadata edit code from the core, and an extension that replicates the
functionality (with the bugs fixed, I hope). In the meantime, I am taking
ownership of this bug so that it doesn't clutter other people's lists.

Moved the code to the "MetadataEdit" extension in r62740.

I am closing this bug as FIXED and I just created bug 22594 in "MediaWiki extensions" product for the bugs you pointed out in comment #0 ("show changes on the edit page does not include the metadata" was fixed in r62740 though). Please provide a new patch for the fixes against the extension if you can.