Fix #16: issue with removing folders

[morgante]

Fixes #16 by slicing the outputs to the length of inputs.

[ludoo]

This is a fix, but there's a potential corner case. State has resources matching

names = ["one", "two", "three"]

and then change to

names = ["one", "three"]

and run terraform output. The outputs will be incorrect imho. I would prefer an error that forces removing outputs until state matches vars. What do you think?

[ludoo]

@averbuks read my comment above...

[morgante]

The outputs will be incorrect imho.

Are you sure?

Only until/unless you run terraform apply. I don't think there should be any expectation that a Terraform config with un-applied changes produces reasonable results.

In fact, it would be the same outcome even without this. This is truncating the list, but the out

and run terraform output. The outputs will be incorrect imho. I would prefer an error that forces removing outputs until state matches vars. What do you think?

We should not force people to edit module internals simply to apply a perfectly valid config.

[ludoo]

I misinterpred the order of execution, so disregard my previous comments! Thanks @morgante for pointing that out privately :)

[ludoo]

I mulled this over a bit as there are similar issues in the service accounts module, and there's something I can't wrap my head around.

Removing an element from the names variable triggers output errors in zipmaps as the resource length in state does not match names length, and this I get of course (and slicing fixes it).

What I don't get is why a similar error isn't raised when an element is added to the names variable. The outputs length should still be mismatched vs name length, and slicing it should of course make no difference, but I don't seem to be able to reproduce this case.

Can someone who understands Terraform internals shed some light here? Is the evaluation only done when destroying resources, which resonates with the issues open in the Terraform repository on this subject, that mostly seem to deal with destroy operations?

[aaron-lane]

@ludoo what is the output in the scenario of adding an extra name?

[ludoo]

@ludoo what is the output in the scenario of adding an extra name?

What you'd expect after a successful apply. The issue is only when deleting a resource, either through a change in inputs or when destroying, so Morgante's patch addresses it.