Update Golang to v1.15.0-rc.1

[justaugustus]

What type of PR is this?

/kind cleanup
/area dependency release-eng
/sig release

What this PR does / why we need it:

Update Golang to v1.15.0

Depends on fixes in earlier PRs (which must also be included if go1.15 support is backported):

• Fix int->string casts #93425 (int->string casts)
• Add subjectAltName to test serving certificates #93426 (add subjectAltName to serving certificates)

Followups (which must also be done in earlier releases if go1.15 support is backported):

• update CI images to go1.15rc1 - releng: Update variants (kubekins, krte) to use go1.15rc1 test-infra#18475
• update CI jobs to use go1.15.rc1 images (bot PR)
• update lint-dependencies to stop exempting golang.org/x/... deps from minimal version selection per Update Golang to v1.15.0-rc.1 #93264 (comment) - Remove golang.org exception for preferring latest minimal version #93603
• once 1.15.0 is released, set minimum_go_version=go1.15 in hack/lib/golang.sh

Signed-off-by: Stephen Augustus saugustus@vmware.com

cc: @kubernetes/release-engineering @kubernetes/release-team-leads @kubernetes/sig-scalability-feature-requests @liggitt @dims
Tracking issue: kubernetes/release#1421

Special notes for your reviewer:

This is testing against a pre-release version of go1.15 (go1.15rc1).
Expect a slew of errors, as various parts of our code are not configured to accept Go pre-release versions.

Also, there will definitely be bazel toolchain + rules_go errors.

Does this PR introduce a user-facing change?:

- Kubernetes is now built with golang 1.15.0-rc.1.
- The deprecated, legacy behavior of treating the CommonName field on X.509 serving certificates as a host name when no Subject Alternative Names are present is now disabled by default. It can be temporarily re-enabled by adding the value x509ignoreCN=0 to the GODEBUG environment variable.

[justaugustus]

/test pull-kubernetes-verify

[FiloSottile]

• only update golang.org dependencies that have release-branch.go1.15 branches:

  hack/pin-dependency.sh golang.org/x/crypto  release-branch.go1.15
  hack/pin-dependency.sh golang.org/x/mod     release-branch.go1.15
  hack/pin-dependency.sh golang.org/x/net     release-branch.go1.15
  hack/pin-dependency.sh golang.org/x/text    release-branch.go1.15
  hack/pin-dependency.sh golang.org/x/tools   release-branch.go1.15
  hack/pin-dependency.sh golang.org/x/xerrors release-branch.go1.15
  

Please don't use the release branches of the golang.org subrepos. They are not what you might think they are: we make release branches to track the version that is vendored into a Go release, not the version that is compatible with a Go release. These release branches are not documented and not supported, and if there is a security vulnerability in a package that is not vendored into the standard library, they will not get the update. You should treat golang.org modules like any other module.

[justaugustus]

Thanks @FiloSottile! So you're saying we'd be better suited targeting the master branch for the golang/x/... tools instead?

[FiloSottile]

Thanks @FiloSottile! So you're saying we'd be better suited targeting the master branch for the golang/x/... tools instead?

Yes, if that's your policy for other dependencies. If you are using Go modules, the standard thing to track would be latest, which translates to master if there are no semver tags, and to the latest tag if there is one.

[liggitt]

/lgtm
/approve

added followups to the description

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: justaugustus, liggitt

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[justaugustus]

added followups to the description

Thanks @liggitt! Full tracking issue is here and I'll get the follow-ups added to it: kubernetes/release#1421

[liggitt]

--- FAIL: TestCustomResourceCascadingDeletion
garbage_collector_test.go:960: expected dependent "dependentqdrg7" to be deleted

which isn't normally a flaky test

/retest

[dims]

@FiloSottile thanks for the guidance!