Honeybadger.context returns Honeybadger::Agent when passing a block

[d4rky-pl]

This is something that I missed when implementing #541 (sorry! 🙏) that may be annoying to people wanting to use the local contexts: If we pass a block to Honeybadger.context I would expect the return value to be the result of the block, rather than the Honeybadger::Agent instance.

Imagine a case we have a critical payments-related process in our application and we want to make sure that all errors triggered in this process are tagged. Pseudocode:

class SuperImportantPaymentProcessing
  def call
    # bunch of things happening
    { success: true, charge: }
  end
end

With the current implementation we need to either create additional variable before the block to make sure the return value from #call remains the same:

class SuperImportantPaymentProcessing
  def call
    result = nil
    Honeybadger.context({ tags: ['critical', 'payments'] }) do
      # bunch of things happening
      result = { success: true, charge: }
    end
    result
  end
end

or we have to use return explicitly:

class SuperImportantPaymentProcessing
  def call
    Honeybadger.context({ tags: ['critical', 'payments'] }) do
      # bunch of things happening
      return { success: true, charge: }
    end
  end
end

While it still works, it feels unexpected. I'm not sure if there's any actual API level expectation that Honeybadger.context returns Agent instance (it's undocumented which is why I missed it) but I think it could make sense to modify the behaviour. I just noticed that the reason it returns Agent instance is to allow chaining, e.g. Honeybadger.context.clear!. I think it makes sense without the block but I would still modify the behaviour for the block version.

Having the behaviour modified would also pair with rescue blocks well, e.g.

class SuperImportantPaymentProcessing
  def call
    Honeybadger.context({ tags: ['critical', 'payments'] }) do
      # bunch of things happening
      { success: true, charge: }
    rescue PaymentError => e
      Honeybadger.notify(e) # this still gets tagged!
      { success: false }
    end
  end
end

Let me know what you think and I can prep the PR with a fix.