Various unusual values for integer-type parameters to the Action API will no longer be accepted. Acceptable values will consist of an optional sign (ASCII `+` or `-`) followed by 1 or more ASCII digits.

Values that were formerly allowed, and will now result in a "badinteger" error, include:

Values with extraneous whitespace, such as " 1".
"1.9", formerly interpreted as "1".
"1e1", formerly interpreted as either "1" or "10" at various times.
"1foobar", formerly interpreted as "1"
"foobar", formerly interpreted as "0".

Most clients should already be using correct formats, unless they are taking direct user input without validation.

This change will most likely go out to Wikimedia wikis with 1.35.0-wmf.19. See https://www.mediawiki.org/wiki/MediaWiki_1.35/Roadmap for a schedule.

Brad Jorsch (Anomie)
Senior Software Engineer
Wikimedia Foundation