== The problem ==
While developing a bot I've just figure out that a query on the [transcludedin](https://www.mediawiki.org/wiki/API:Transcludedin) API module with a non-numeric `tinamespace` / `gtinamespace` throws an error 500 but only after 60 seconds of execution.
== Proof of concept ==
* https://en.wikipedia.org/w/api.php?action=query&titles=A&generator=transcludedin>inamespace=TEST
* https://en.wikipedia.org/w/api.php?action=query&titles=A&prop=transcludedin&tinamespace=TEST
* https://en.wikipedia.org/w/api.php?action=query&titles=A&generator=linkshere&glhnamespace=TEST
*https://en.wikipedia.org/w/api.php?action=query&titles=A&prop=linkshere&glhnamespace=TEST
== Normal usage examples ==
* https://en.wikipedia.org/w/api.php?action=query&titles=A&generator=transcludedin>inamespace=0
* https://en.wikipedia.org/w/api.php?action=query&titles=A&prop=transcludedin&tinamespace=0
* https://en.wikipedia.org/w/api.php?action=query&titles=A&generator=linkshere&glhnamespace=0
* https://en.wikipedia.org/w/api.php?action=query&titles=A&prop=linkshere&glhnamespace=0
== Notes ==
As far I can see this is not a problem related to all API modules with a namespace filter e.g. `allpages` quits immediately as expected:
* https://en.wikipedia.org/w/api.php?action=query&titles=A&generator=allpages&gapnamespace=TEST
Here some MediaWiki versions that I think are **not** affected:
* <=1.24 (has not transcludedin generator)
* 1.27.4
* 1.29.1
Now I really have no time to further investigate because tomorrow morning I'm in an office.
== Definition ==
* [includes/api/ApiQueryBacklinksprop.php](https://doc.wikimedia.org/mediawiki-core/master/php/ApiQueryBacklinksprop_8php_source.html)