Can't have a Bogus FinishWith configured

Since Bogus allows only a single FinishWith method, the way AutoBogus works its magic makes it impossible for someone to configure a FinishWith for a Type like this:

public class PersonBuilder : AutoFaker<Person>
{
//    ... props
}

// ...
var personBuilder = new PersonBuilder().FinishWith((f, p) => 
{ 
    // something 
})
.Generate();

This is common in a scenario where a property doesn’t have a setter and has to be configured through methods. So something like this:

public class PersonBuilder : AutoFaker<Person>
{
    public PersonBuilder WithAddresses(int count = 1)
    {
        // store how many addresses must be generated
    }

    public PersonBuilder WithEmails(int count = 1)
    {
        // store how many emails must be generated
    }

    // other methods for Collections without setter

   public override Generate(string ruleSets = null)
   {
        FinishWith((f, p) =>
        {
            // Calls methods that populate Addresses, Emails, etc.
        });
   }
}

From what I looked at the code, the culprit is this line.

I see a few ways this could be fixed: Bogus could allow multiple finalizers (I don’t see why this isn’t allowed anyway), or AutoBogus could execute that code in a different way.

What do you think? Is this something that should be improved?

[nickdodd79]

Hey @metareven

Thanks for reminding me of this one. I had made the changes a while ago, just hadn’t release it.

This capability has now been included in v2.8.

Nick.

[bchavez]

Hey @nickdodd79 @akamud,

I really apologize for the delay. I’ve been busy preparing for job interviews at a few places. Also been thinking a lot about moving Bogus to the .NET Foundation as part of their new Project Maturity Model announced early this week at .NET Conf; mostly as a move to gain more users and as a way of establishing confidence for bigger businesses. @nickdodd79 , if you’d like to be a part of it and you think it’s right for you, please send me an email and we can talk more about it. Essentially, PML Level 3 and 4 require more than 1 maintainer on the project.

As for Bogus having multiple .FinishWith methods, I’m not sure. The conceptional API usage for Faker<T> is that the last-call wins. IE:

• Faker<T>.RuleFor(x.Prop, f => 1) and then if the same rule for the member is specified again,
• Faker<T>.RuleFor(x.Prop, f => 2) that f => 2 wins and f =>1 rule is over-written.

The same conceptual API consistency applies to .FinishWith( f, t =>); last-call wins.

At least from Bogus’ point of view; I’m not sure how helpful keeping track of past rules is important to Faker<T> other than in this specific case here.

• Do we modify Faker<T> to allow this implementation detail scenario? I’m not sure yet but inclined to think maybe not, but I’m open to discussing more. My mind can always be changed tho.

I like method 3 that you mentioned as a possible workaround for this issue is for AutoBogus to store a reference to any finalizers being kept track in Faker<T> and call them after AutoBogus is done hooking FinishWith. For sure, I can help with this by opening up some kind of accessor to a member if anything is private. But it seems like we already have that protected accessor set: https://github.com/bchavez/Bogus/blob/master/Source/Bogus/Faker[T].cs#L54

PR if you need anything more opened if it could help your implementation.

Lastly, another possibility if we want to get crazy hard-core about it; any Action is really a delegate under the hood; specifically, a multi-cast delegate? So, as a crazy C# hack, you technically can combine two Action methods in C#; like this check it out:

void Main()
{
   Action a = () => "Hello A".Dump();
   Action b = () => "Hello B".Dump();
   Action c = a + b;
   c();
}

Hello A
Hello B

IIRC, under the hood, the C# compiler will use Delegate.Combine(a,b) to produce c. Thereby hacking your way around this neat little problem of needing to keep track of a ‘list’ of invocations. 😈 Specifcally, get the FinalizeAction.Action and attach your custom hook … might work?

Let me know your thoughts.

Thanks, Brian

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