Cross post. mediawiki-api-announce is highly recommended if you write code consuming the Action API. 

---------- Forwarded message ---------
From: Brad Jorsch (Anomie) <>
Date: Wed, Jul 25, 2018 at 8:43 AM
Subject: [Mediawiki-api-announce] BREAKING CHANGE: Some missing parameter error codes are changing
To: <>

It was noticed[1] that the error messages for "missing parameter" errors were not including the module prefix, for example a query to action=query&list=search could complain that the "search" parameter must be set when the actual parameter name is "srsearch". This extends to the error code, which in this example is "nosearch" rather than "nosrsearch".

This is now fixed, and should be deployed to Wikimedia sites with MediaWiki 1.32.0-wmf.15 and later. See for a schedule.

If your client is checking for specific missing parameter error codes, it may need to be updated for the changed codes.


Brad Jorsch (Anomie)
Senior Software Engineer
Wikimedia Foundation
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