feat: extend version information with more detailed version fields

- Add new version fields to version.Info struct:
  * EmulationMajor and EmulationMinor to track emulated version
  * MinCompatibilityMajor and MinCompatibilityMinor for compatibility tracking
- Update related code to populate and use these new fields
- Improve version information documentation and OpenAPI generation
- Modify version routes and documentation to reflect new version information structure

Author: yongruilin

api/openapi-spec/swagger.json

@@ -243,8 +243,14 @@ func TestVersion(t *testing.T) {
 	}
 	expectedInfo := utilversion.Get()
 	kubeVersion := compatibility.DefaultKubeEffectiveVersionForTest().BinaryVersion()
+	emulationVersion := compatibility.DefaultKubeEffectiveVersionForTest().EmulationVersion()
+	minCompatibilityVersion := compatibility.DefaultKubeEffectiveVersionForTest().MinCompatibilityVersion()
 	expectedInfo.Major = fmt.Sprintf("%d", kubeVersion.Major())
 	expectedInfo.Minor = fmt.Sprintf("%d", kubeVersion.Minor())
+	expectedInfo.EmulationMajor = fmt.Sprintf("%d", emulationVersion.Major())
+	expectedInfo.EmulationMinor = fmt.Sprintf("%d", emulationVersion.Minor())
+	expectedInfo.MinCompatibilityMajor = fmt.Sprintf("%d", minCompatibilityVersion.Major())
+	expectedInfo.MinCompatibilityMinor = fmt.Sprintf("%d", minCompatibilityVersion.Minor())
 
 	if !reflect.DeepEqual(expectedInfo, info) {
 		t.Errorf("Expected %#v, Got %#v", expectedInfo, info)

api/openapi-spec/v3/version_openapi.json

@@ -468,15 +468,15 @@ func (v *Version) Info() *apimachineryversion.Info {
 		return nil
 	}
 	// in case info is empty, or the major and minor in info is different from the actual major and minor
-	v.info.Major = itoa(v.Major())
-	v.info.Minor = itoa(v.Minor())
+	v.info.Major = Itoa(v.Major())
+	v.info.Minor = Itoa(v.Minor())
 	if v.info.GitVersion == "" {
 		v.info.GitVersion = v.String()
 	}
 	return &v.info
 }
 
-func itoa(i uint) string {
+func Itoa(i uint) string {
 	if i == 0 {
 		return ""
 	}

pkg/controlplane/instance_test.go

@@ -16,5 +16,5 @@ limitations under the License.
 
 // +k8s:openapi-gen=true
 
-// Package version supplies the type for version information collected at build time.
+// Package version supplies the type for version information.
 package version

pkg/generated/openapi/zz_generated.openapi.go

@@ -20,15 +20,25 @@ package version
 // TODO: Add []string of api versions supported? It's still unclear
 // how we'll want to distribute that information.
 type Info struct {
-	Major        string `json:"major"`
-	Minor        string `json:"minor"`
-	GitVersion   string `json:"gitVersion"`
-	GitCommit    string `json:"gitCommit"`
-	GitTreeState string `json:"gitTreeState"`
-	BuildDate    string `json:"buildDate"`
-	GoVersion    string `json:"goVersion"`
-	Compiler     string `json:"compiler"`
-	Platform     string `json:"platform"`
+	// Major is the major version of the binary version
+	Major string `json:"major"`
+	// Minor is the minor version of the binary version
+	Minor string `json:"minor"`
+	// EmulationMajor is the major version of the emulation version
+	EmulationMajor string `json:"emulationMajor,omitempty"`
+	// EmulationMinor is the minor version of the emulation version
+	EmulationMinor string `json:"emulationMinor,omitempty"`
+	// MinCompatibilityMajor is the major version of the minimum compatibility version
+	MinCompatibilityMajor string `json:"minCompatibilityMajor,omitempty"`
+	// MinCompatibilityMinor is the minor version of the minimum compatibility version
+	MinCompatibilityMinor string `json:"minCompatibilityMinor,omitempty"`
+	GitVersion            string `json:"gitVersion"`
+	GitCommit             string `json:"gitCommit"`
+	GitTreeState          string `json:"gitTreeState"`
+	BuildDate             string `json:"buildDate"`
+	GoVersion             string `json:"goVersion"`
+	Compiler              string `json:"compiler"`
+	Platform              string `json:"platform"`
 }
 
 // String returns info as a human-friendly version string.

staging/src/k8s.io/apiextensions-apiserver/pkg/generated/openapi/zz_generated.openapi.go

@@ -1108,7 +1108,7 @@ func installAPI(name string, s *GenericAPIServer, c *Config) {
 		}
 	}
 
-	routes.Version{Version: c.EffectiveVersion.BinaryVersion().Info()}.Install(s.Handler.GoRestfulContainer)
+	routes.Version{Version: c.EffectiveVersion.Info()}.Install(s.Handler.GoRestfulContainer)
 
 	if c.EnableDiscovery {
 		if c.FeatureGate.Enabled(genericfeatures.AggregatedDiscoveryEndpoint) {

staging/src/k8s.io/apimachinery/pkg/util/version/version.go

@@ -372,7 +372,7 @@ func TestServerRunWithSNI(t *testing.T) {
 				t.Fatalf("failed to connect with loopback client: %v", err)
 			}
 			if expected := &v; !reflect.DeepEqual(got, expected) {
-				t.Errorf("loopback client didn't get correct version info: expected=%v got=%v", expected, got)
+				t.Errorf("loopback client didn't get correct version info: expected=%v got=%v", *expected, *got)
 			}
 
 			select {
@@ -463,9 +463,13 @@ func certSignature(cert tls.Certificate) (string, error) {
 
 func fakeVersion() version.Info {
 	return version.Info{
-		Major:      "42",
-		Minor:      "42",
-		GitVersion: "42.42",
+		Major:                 "42",
+		Minor:                 "42",
+		EmulationMajor:        "42",
+		EmulationMinor:        "42",
+		MinCompatibilityMajor: "42",
+		MinCompatibilityMinor: "41",
+		GitVersion:            "42.42",
 	}
 }