FeatureSpec: featuregate.FeatureSpec{Default: false, PreRelease: featuregate.Deprecated},
		DeprecationMessage: "The PublicKeysECDSA feature gate is deprecated and will be removed when v1beta3 is removed." +
			" v1beta4 supports a new option 'ClusterConfiguration.EncryptionAlgorithm'.",
	},
	RootlessControlPlane: {FeatureSpec: featuregate.FeatureSpec{Default: false, PreRelease: featuregate.Alpha},

Module example.com/retract/self/prerelease is a module that retracts its own
latest version and all other release version.

A pre-release version higher than the highest release version is still
available, and that should be matched by @latest.

-- .mod --
module example.com/retract/self/prerelease

go 1.15

-- .info --
{"Version":"v1.9.1-pre"}

-- p.go --

// then the pseudo-version uses form (2) or (3), making it a prerelease for the next
// possible semantic version after vX.Y.Z. The leading 0 segment in the prerelease string
// ensures that the pseudo-version compares less than possible future explicit prereleases
// like vX.Y.(Z+1)-rc1 or vX.Y.(Z+1)-1.
//

		return v[:j]
	}
	return v[:i] + "." + pv.minor
}

// Prerelease returns the prerelease suffix of the semantic version v.
// For example, Prerelease("v2.1.0-pre+meta") == "-pre".
// If v is an invalid semantic version string, Prerelease returns the empty string.
func Prerelease(v string) string {
	pv, ok := parse(v)
	if !ok {
		return ""
	}
	return pv.prerelease
}

// Build returns the build suffix of the semantic version v.

    name: details
  - image: docker.io/istio/proxyv2:1.3.0-prerelease
    name: istio-proxy
---
# details-v1-pod-overwritten-sidecar has a custom sidecar version injected and
# therefore should not match the injector version.
apiVersion: v1
kind: Pod
metadata:
  labels:
    app: details
  annotations:
    sidecar.istio.io/proxyImage: docker.io/istio/proxyv2:1.3.0-prerelease
  name: details-v1-pod-overwritten-sidecar

Module example.com/retract/self/prerelease is a module that retracts its own
latest version and all other release version.

A pre-release version higher than the highest release version is still
available, and that should be matched by @latest.

-- .mod --
module example.com/retract/self/prerelease

go 1.15

-- .info --
{"Version":"v1.0.0"}

-- p.go --

	}

	previousVersion := semver.New(v.Major(), v.Minor()-1, v.Patch(), v.Prerelease(), v.Metadata())

	// If the previous version is not published yet, use the latest one
	if exists, err := image.Exists(imageToCheck + ":" + previousVersion.String()); err != nil {
		return err
	} else if !exists {
		previousVersion = semver.New(v.Major(), v.Minor()-2, v.Patch(), v.Prerelease(), v.Metadata())
	}

	previousSupportedVersion = previousVersion.String()

The deprecated package is present in this version (which is @latest) but
is deleted in a newer prerelease version.

-- .mod --
module example.com/missingpkg
-- .info --
{"Version":"v1.0.0"}
-- lib.go --
package lib
-- deprecated/deprecated.go --

// available throughout Kubernetes binaries.
var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
	CRDValidationRatcheting:      {Default: true, PreRelease: featuregate.Beta},
	CustomResourceFieldSelectors: {Default: true, PreRelease: featuregate.Beta},

	if len(newK8sVersion.PreRelease()) == 0 {
		return nil
	}
	// If the user has specified that unstable versions are fine, then no error should be returned
	if allowExperimentalUpgrades {
		return nil
	}
	// If this is a release candidate and we allow such ones, everything's fine
	if strings.HasPrefix(newK8sVersion.PreRelease(), "rc") && allowRCUpgrades {
		return nil
	}