Semanticmediawiki: Graph format through Special:Ask gives fatal error

[djoris]

Setup and configuration

Following is config of our server & the SMW sandbox (both showing the error)

• SMW version: 2.5.5 & 3.0.0-alpha (59bd015)
• MW version: 1.27.3 & 1.30.0-rc.0
• PHP version: 5.5.38 & 5.6.30-0
• DB system (MySQL, Blazegraph, etc.) and version: MySQL 14.4 & MariaDB 10.0.33
• SRF: 2.5.4 & 3.0.0-alpha (da5e145)
• Graphviz: 2.1.0

Issue

Creating any query that has at least one result, through Special:Ask with output format graph (graphviz) results in a 500 server error:

Fatal error: Call to a member function getFulltext() on null in /../extensions/GraphViz/GraphViz_body.php on line 500

This issue only pertains queries through Special:Ask, not inline queries.

Stack trace

n/a (fatal error)

Steps to reproduce

Example data and working inline query in https://sandbox.semantic-mediawiki.org/wiki/Issue/Graphviz

1. Go to: Special:Ask
2. Create a condition that matches at least one page, such as: [[ArticleAuthor::+]]. Optionally choose a Printout selection.
3. Set Format to Graph. Optionally select or remove arguments for the format.
4. Choose Find results
   The resulting page gives the fatal error:
   Fatal error: Call to a member function getFulltext() on null in /../w/extensions/GraphViz/GraphViz_body.php on line 500
   This can be replicated with several conditions, several properties (or none), and on multiple wikis.

[kghbln]

Thanks a lot for reporting. I think this is a GraphViz error. I actually reported the very same error at T180376 two weeks ago.

Moreover the error log gives me:

[Wed Nov 29 16:10:30.283412 2017] [:error] [pid 6374] [client 145.131.226.106:52869] PHP Fatal error:  Class 'OOUI\\WikimediaUITheme' not found in /../w/includes/OutputPage.php on line 3986, referer: https://sandbox.semantic-mediawiki.org/w/index.php?title=Issue/Graphviz&action=submit

So this may also be some broken interaction with MediaWiki core.

[kghbln]

Moreover the error log gives me:

Sometimes... Of course there was an "issue": At the same time I upgraded from 1.29.2 to 1.30.0-rc.0 which took a minute or so. So having this is kinda expected during the upgrade. There is no related core issue.

[mwjames]

A quick note.

This relates to SRF not SMW (Graph is part of SRF not SMW).

Fatal error: Call to a member function getFulltext() on null in /var/www/htdocs/mw/02100/w/extensions/GraphViz/GraphViz_body.php on line 500

If GraphViz_body.php crashes for some reason then it should be no
surprise that Special:Ask can't handle the situation and it is not
an indicator that something is wrong with Special:Ask.

Someone should fix the issue of getFulltext() on null in GraphViz_body.php.

Cheers

On 11/30/17, Joris Dirks [e-mail] wrote:

Setup and configuration

Following is config of our server & the SMW sandbox (both showing the
error)

• SMW version: 2.5.5 & 3.0.0-alpha (59bd015)
• MW version: 1.27.3 & 1.30.0-rc.0
• PHP version: 5.5.38 & 5.6.30-0
• DB system (MySQL, Blazegraph, etc.) and version: MySQL 14.4 & MariaDB
  10.0.33

Issue

Creating any query that has at least one result, through Special:Ask with
output format graph (graphviz) results in a 500 server error:
Fatal error: Call to a member function getFulltext() on null in /var/www/htdocs/mw/02100/w/extensions/GraphViz/GraphViz_body.php on line 500
This issue only pertains queries through Special:Ask, not inline queries.

Stack trace

n/a (fatal error)

Steps to reproduce

Example data and working inline query in
https://sandbox.semantic-mediawiki.org/wiki/Issue/Graphviz

1. Go to: Special:Ask
2. Create a condition that matches at least one page, such as:
   [[ArticleAuthor::+]]. Optionally choose a Printout selection.
3. Set Format to Graph. Optionally select or remove arguments for the
   format.
4. Choose Find results
   The resulting page gives the fatal error.

This can be replicated with several conditions, several properties (or
none), and on multiple wikis.

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[kghbln]

A quick note.

Thanks for the info. So back to T180376.