Complexity has no default

Enabling the complexity rule with only a severity has no effect. We have tried to give sane defaults to all rules, and I think this should be no exception. I don’t know what a good number would be, though.

[SpadeAceman]

Lower complexity is of course better, but trying to determine a sensible, one-size-fits-all default is tricky.

If we’re going for an “only stop me if I’m approaching insanity” sort of default, then it sounds like 20 could indeed work, based on the recommendations and anecdotal evidence I’ve assembled below. (Myself, I’d lean toward defaulting to 10 or 15.)

• https://msdn.microsoft.com/en-us/library/ms182212.aspx
  • “The rule reports a violation when the cyclomatic complexity is more than 25.”
• http://www.aivosto.com/project/help/pm-complexity.html
  • “The original, usual limit for a maximum acceptable value for cyclomatic complexity is 10. Other values, such as 15 or 20, have also been suggested. Regardless of the exact limit, if cyclomatic complexity exceeds 20, you should consider it alarming.”
• http://checkstyle.sourceforge.net/config_metrics.html#CyclomaticComplexity
  • “When it comes to code quality measurement by this metric level 10 is very good level as a ultimate target (that is hard to archive). Do not be ashamed to have complexity level 15 or even higher, but keep it below 20 to catch really bad[ly] designed code automatically.”
• http://www.elijahmanor.com/control-the-complexity-of-your-javascript-functions-with-jshint/
  • “In the 2nd edition of Steve McConnell’s Code Complete he recommends that a cyclomatic complexity from 0 to 5 is typically fine, but you should be aware if the complexity starts to get in the 6 to 10 range. He further explains that anything over a complexity of 10 you should strongly consider refactoring your code.”
• http://davetayls.me/blog/2013/07/01/how-will-i-keep-javascript-code-quality-hight-jshint/
  • “I have found a value of 6 gives a good balance of separation and being pragmatic.”
• http://ariya.ofilabs.com/2013/05/continuous-monitoring-of-javascript-code-complexity.html
  • a complexity limit of 15 is used in the example
• https://blogs.msdn.microsoft.com/zainnab/2011/05/17/code-metrics-cyclomatic-complexity/
  • “The original limit of 10 as proposed by McCabe has significant supporting evidence, but limits as high as 15 have been used successfully as well. […] an organization can pick a complexity limit greater than 10, but only if it is sure it knows what it is doing and is willing to devote the additional testing effort required by more complex modules.”
• http://programmers.stackexchange.com/questions/194061/cyclomatic-complexity-ranges
  • example 1
    • 1-5: easy to maintain
    • 6-10: difficult
    • 11-15: very difficult
    • 20+: approaching impossible
  • example 2
    • 1-10: simple and easy to understand
    • 11-20: may still be comprehensible, but testing becomes more difficult
    • 21-50: can only be fully grasped and tested with great difficulty and effort
    • 51+: certainly unmaintainable

[platinumazure]

@Mardak Please open a new issue so we can discuss further. Thanks!