Selectors in ObjectMetricSource's weren't being persisted through roundtrip conversions, and this wasn't caught because we had no fuzzer testing MetricIdentifier selectors
Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
code-gen: output golint compliant 'Generated by' comment
New PR instead of reopening #58115 because /reopen did not work.
This won't be ready to merge until the upstream https://github.com/kubernetes/gengo/pull/94 merges. Once that merges, the second commit will be changed to godep-save.sh and update-staging-godeps.sh, and the last commit will be changed to update-all.sh
The failing test is due to the upstream changes not being merged yet
```devel-release-note
Go code generated by the code generators will now have a comment which allows them to be easily identified by golint
```
Fixes#56489
Automatic merge from submit-queue (batch tested with PRs 56410, 56707, 56661, 54998, 56722). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Fix autoscaling API documentation
**What this PR does / why we need it**:
This PR fixes the API documentation generated for HorizontalPodAutoscaler resource.
**Which issue(s) this PR fixes**:
The current API doc for `MetricSpec` and `MetricStatus` is confusing. Users get no idea what can be used as the value for the `type` field, because the doc says this:
```
type is the type of metric source. It should match one of the fields below.
```
While acceptable in the source code, it makes no senses when reading the API doc, especially when the "`type`" field is listed as the last row in a table (see: https://kubernetes.io/docs/api-reference/v1.8/#metricspec-v2beta1-autoscaling )
**Special notes for your reviewer**:
This PR makes no changes to the code behavior.
**Release note**:
```release-note
NONE
```