Last modified: 2011-05-02 18:28:20 UTC
If <math> failed to parse due to an unknown/invalid argument, e.g.
<math>\abcdef</math> the errormessage contains the wrong argument twice:
"Failed to parse (unknown error\abcdef): \abcdef"
[[MediaWiki:math_failure]] ([[MediaWiki:math_unknown_error]] argument): argument
Please delete the first output of the argument.
It's only the same if the formula has only one function. The second "argument" in the error message is the entire formula.
The real bug is that it says "unkown error" instead of "unkown function".
Not sure when the change occured, but the error message now produced is "unknown function" and as commented in comment 1 the output argument is not really duplicate.