force creating new condition if type is changed

[smaeda-ks]

#517

background: Fastly API doens't support updating the type field once it's created.

And because fastly_service_v1 is a mono resource, the usual ForceNew approach doesn't work as it will attempt to re-create a fastly_service_v1 resource as a whole. CustomizeDiff is also not an option either as condition is a nested block.

So we unfortunately implement it in this way, where we silently call DELETE and CREATE if type attribute is changed. Otherwise, call UPDATE.

[Integralist]

Thanks @smaeda-ks

The implementation makes sense to me.

Of course it would be preferable for the API to support this feature rather than us implementing this in the Terraform provider (as has been mentioned by others this can lead to fragmentation across API clients).

That said, this feature is currently broken for users. Due to the potential time it would take to get the API to support this, I'm OK seeing this PR merged/released, with the intention that we actively push for the API to be updated and then we can come back and update this logic accordingly.

Question: Are there any downsides/side-effects that I'm not considering that would make us what to tread cautiously before merging?

[smaeda-ks]

@Integralist

Question: Are there any downsides/side-effects that I'm not considering that would make us what to tread cautiously before merging?

No, I don't expect any side-effects by this change. Thanks

[Integralist]

LGTM. Thanks for adding the test.