Testing AxisDependency before using the data

[AndreasIgelCC]

If disabling a YAxis and not setting the datasets AxisDependency correct, there could be strange behaviour (see #665). This change will notify the developer of wrong dataset-settings.

[danielgindi]

I'm actually not sure that we should pollute the console here.
Imagine adding data on the other axis - but hiding that axis... A common use case, but will produce a warning!
@PhilJay what do you say?

[AndreasIgelCC]

Do you have an example in this framework how to show that warning without polluting the console?
Just adding the data on the other axis would be a solution, just removing this data would be a solution too. But in my opinion we should give a feedback if the developer makes a mistake in using the framework (like adding data to disabled axis).

[danielgindi]

We have no way to know if it's a mistake. Therefore no warning...
The NSLayoutConstraints for example - do issue warnings - when they know that you have absolutely positively made a mistake, due to two colliding constraints.
In our case - what you are describing is completely valid.

[danielgindi]

It's not even possible (to my knowledge) to do conditional warning like "if you're in debug mode", because those macros get compiled and removed when building the Framework release.

[AndreasIgelCC]

Thank you for your feedback! I agree there is a usecase where developer dont want to show axis but want to show data. So always printing a warning would not be a good solution!

Just one question: Print should only write to console when its in debug mode or do I have a misunderstanding in context of frameworks?

[danielgindi]

I don't really know. From my experience console log works in prouction also. In objc projects I use macros to disable logs in release build. It's possible that it's different in Swift- but still it's too much verbosity...

[pmairoldi]

Swift's print function works differently. It does not actually print to the device logs like NSLog does. Could precondition be what is needed here?

[danielgindi]

A precondition would mean that the user is absolutely wrong by having the axis invisible... Which is not true
http://stackoverflow.com/questions/29673027/difference-between-precondition-and-assert-in-swift

[AndreasIgelCC]

You are right, the developer might have disabled the axis because he just dont want to see it. Thinking about the topic deeply, I find no condition in which we can say: "The chart-config is invalid!". So you are right in closing the pull request.