Please clarify, is the Code Contracts is similar to FxCop and StyleCop? As per the online references, we need to add Codes for implementing the code contract conditions inside the function of existing code.
public void Initialize(string name, int id)
{
Contract.Requires(!string.IsNullOrEmpty(name));
Contract.Requires(id > 0);
Contract.Ensures(Name == name);
//Do some work
}
Usually in FxCop, the code we want to check will be in separate Dll and the Class library which includes the rules to check will be in separate dll. Likewise whether we can create separate class library for Code contract to rule the existing code?
Please confirm..
disclaimer: you'd better take their current docs and read them through, write down the features and then compare them. What I wrote below is some facts I remembered long time ago about their core functionalities and I can't guarantee you that they are not outdated and now-wrong. For example, someone could write some complex&heavy rules for FxCop that behave as Contracts do. This is why I'm marking it as community-wiki. Please correct me if I'm wrong anywhere.
No they are not similar, although they share common target: help you find bugs.
FxCop is a "static analyzer", which inspects your code and tries to find "bad patterns". You will not see any FxCop rules/effects during runtime. FxCop has a set of "rules" that will be used during inspection and it reports to you whenever it finds a rule to be broken. Rules can be very easy and nitpicking like you must initialize every variable or you must name classes with uppercase or complex ones like you shouldn't have more than one loop in a method. Some rules are available by the standard installation, and you can expand the ruleset with your own rules.
CodeContracts is two-sided. At the most basic level, it is a set of helper methods, like throw if argument 'foo' is null. At runtime, when someone passes a null, it will throw. Just that simple. However, if you use those helper methods correctly and widely in your code, you will be able to run an additional static analyzer. It will scan your code, find all usages of those helper methods, and will try to automatically detect any places where their contracts are not satisfied. So, with the "argument is null" example, it will try to find all usages of that function, check who calls it with what args, it will try to deduce (prove) if that arg can be null at all anytime, and will warn you if it finds such case. There are more types of such validators other than just not-null, but you can't add/write your own. I mean, you could add more such helper validators, but the static analyzer wouldn't pick them up (it's too hard to write a general theorem prover for any rule).
CodeContracts is more powerful in its analyses than FxCop, but limited in diversity and scope. CodeContracts cannot check the structure of the code: it will not check the number of loops, code complexity, names of methods, code hierarchy, etc. It can only attempt to prove/disprove some contracts (runtime requirements) of some methods/interfaces. FxCop on the other hand can inspect your code, style, structure, etc, but it will not "prove" or "deduce" anything - it will just check for some bad patterns defined by rules.