chore: unify calling of apidiff

[justinsb]

Following what is done in cluster-api-provider-aws, we always use the Makefile apidiff target.

This means we ignore api diffs if the API is not changing.

NONE

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[k8s-ci-robot]

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[justinsb]

I personally think we want to go further, and ignore packages that are not part of our published contract. For CAPG, I think that is anything that is not under api/. It looks like go-apidiff cannot do that by default, go-apidiff looks like a pretty thing wrapper around golang.org/x/exp/apidiff so we could just write our own. Alternatively we could just do some (more fragile) grep matching.

Background is I that I think we will ignore these diffs anyway, so we aren't getting good signal from the tests. OTOH I do want to see the signal when we change something under api/!

[k8s-ci-robot]

@justinsb: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-cluster-api-provider-gcp-e2e-test	ef7fcba	link	true	/test pull-cluster-api-provider-gcp-e2e-test

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[justinsb]

I had a go at focusing on just the API changes in #1519

[justinsb]

/close

I think #1519 is what we actually want to have a test that gives good signal

[k8s-ci-robot]

@justinsb: Closed this PR.

In response to this:

/close

I think #1519 is what we actually want to have a test that gives good signal

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