What happened:
Deployment resource with replicas is handled differently in client side and server side apply with HPA

What you expected to happen:
With HPA, Deployment should not have replicas and server side apply should detect the conflict. HPA controller does not seem to manege the replica field with mangedFields.

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

https://gist.github.com/inductor/2ff5b8f7e04cde3d649878b761ce31e5

Anything else we need to know?:

Environment:

• Kubernetes version (use kubectl version): v1.18.3
• Cloud provider or hardware configuration: minikube on Docker
• OS (e.g: cat /etc/os-release): Ubuntu 20.04
• Kernel (e.g. uname -a): Linux DESKTOP-0DH0Q95 4.19.104-microsoft-standard Unit test coverage in Kubelet is lousy. (~30%) #1 SMP Wed Feb 19 06:37:35 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
• Install tools: minikube
• Network plugin and version (if this is a network-related bug):
• Others: