Crash when computed help text larger than maximum length

[Chadehoc]

Maximum length for displaying help is 120 in Parser.Default. If a long help text makes the computed length larger than that (when reporting a parsing error), an ArgumentOutOfRangeException is raised.

Details:

In HelpText.AddOptionsImpl, maxLength = GetMaxLength(specifications) is large enough so that remainingSpace below becomes negative, which is passed to HelpText.AddOption as widthOfHelpText, and used there with an exception.

If I manually set the negative remainingSpace to 0 in the debugger, it goes on to an out of memory error. Setting to 1 is ok, but illogical, so there must be another hidden bug that 0 reveals.

Also, this error only occurs with Parser.Default. If I use an unmodified new Parser(s => Console.WriteLine(s.MaximumDisplayWidth)), this prints 120, the same result is returned (error list), but without crashing. So this behaviour also depends on another setting than the maximum length.

[Oddley]

I was also seeing ArgumentOutOfRangeException related to MaximumDisplayWidth. It seems that old versions of mono for non-Windows systems would throw when Console.Width is called, but for newer versions of Mono this is not the case. See #279

[moh-hassan]

Fixed in V2.7+