kubernetes: SSA triggers update events on apply to resource when it is no-op

What happened:

Using SSA patch to create and manage a couple of resources (specifically those, the list may change in the future) resulted in endless hot loop, as each apply increases resourceVersion of the resource even if this is a no-op.

What you expected to happen:

Apply resources once to establish ownership on the fields and forget. Operator should not be triggered by constant resourceVersion changes if does not change any object spec or metadata by a new patch.

How to reproduce it (as minimally and precisely as possible):

Take a sample Deployment or other resource and forcefully apply it multiple times using controller-runtime client.

Anything else we need to know?:

This issue appeared using controller-runtime client implementation, but could be present in other clients. kubectl is not affected.

Environment:

• Kubernetes version (use kubectl version): v1.20.0+aa519d9 and before
• Cloud provider or hardware configuration: aws/openstck, does not matter
• OS (e.g: cat /etc/os-release): ~
• Kernel (e.g. uname -a): ~
• Install tools: ~
• Network plugin and version (if this is a network-related bug): ~
• Others: ~

/sig api-machinery /wg api-expression