diff: Fix overlapping filenames

[apelisse]

The filename can overlap when multiple resources have the same name (but
obviously are of a different type). Include the name of the type in the
file name to prevent the overlap.

What type of PR is this?

/kind bug

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #71920

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Fix overlapping filenames in diff if multiple resources have the same name.

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[towolf]

Disambiguating the name with the kind seems the right solution. Adding namespace would be even better, no? I can have kind: Service, name: test in multiple namespaces. Just saw, disambiguation is keyed with Version.Kind:Namespace.Name. Thanks!

And then I wonder, what you think the intended behaviour is, when I have duplicates of kind and name pairs.

In the cluster this is not possible, but on disk it is. Which dupe will be picked? It's not handling this case is it?

[towolf]

Version is sometimes converted to another storage version in etcd and is returned in another apiVersion. Will this lead to noisy diffs?

[apelisse]

Version is sometimes converted to another storage version in etcd and is returned in another apiVersion. Will this lead to noisy diffs?

That should be irrelevant, because kube-apiserver returns just the version we're asking for (same as the version on disk)

[apelisse]

And then I wonder, what you think the intended behaviour is, when I have duplicates of kind and name pairs.

Yeah, this problem is more general than just diff. I'm also less concerned about diff than I am about apply, because diff is not mutating. I think it deserves another issue if you want to see that use-case fixed.

I'm pretty sure that diff should behave like apply does: you want to see the changes as they are actually going to happen, and I think it is consistent today.

[mengqiy]

/lgtm

[apelisse]

/kind bug
/priority critical-urgent

[liggitt]

Colons aren't cross-platform safe, are they?