added context-based warning suppression to SetEmulationVersion to eliminate test noise

PersistentJZH · PersistentJZH · commit adbd958ba73a · 2025-07-25T14:38:20.000+08:00
Signed-off-by: zhihao jian &lt;zhihao.kan17@gmail.com&gt;
diff --git a/staging/src/k8s.io/component-base/featuregate/feature_gate.go b/staging/src/k8s.io/component-base/featuregate/feature_gate.go
@@ -165,6 +165,8 @@ type MutableVersionedFeatureGate interface {
 	// Otherwise, the emulationVersion will be the same as the binary version.
 	// If set, the feature defaults and availability will be as if the binary is at the emulated version.
 	SetEmulationVersion(emulationVersion *version.Version) error
+	// SetEmulationVersionWithContext is like SetEmulationVersion but accepts a context for controlling behavior.
+	SetEmulationVersionWithContext(ctx context.Context, emulationVersion *version.Version) error
 	// GetAll returns a copy of the map of known feature names to versioned feature specs.
 	GetAllVersioned() map[Feature]VersionedSpecs
 	// AddVersioned adds versioned feature specs to the featureGate.
@@ -543,6 +545,10 @@ func (f *featureGate) GetAllVersioned() map[Feature]VersionedSpecs {
 }
 
 func (f *featureGate) SetEmulationVersion(emulationVersion *version.Version) error {
+	return f.SetEmulationVersionWithContext(context.Background(), emulationVersion)
+}
+
+func (f *featureGate) SetEmulationVersionWithContext(ctx context.Context, emulationVersion *version.Version) error {
 	if emulationVersion.EqualTo(f.EmulationVersion()) {
 		return nil
 	}
@@ -565,7 +571,16 @@ func (f *featureGate) SetEmulationVersion(emulationVersion *version.Version) err
 		newVal := featureEnabled(feature, enabled, known, emulationVersion)
 		oldVal := featureEnabled(feature, f.enabled.Load().(map[Feature]bool), known, f.EmulationVersion())
 		if newVal != oldVal {
-			klog.Warningf("SetEmulationVersion will change already queried feature:%s from %v to %v", feature, oldVal, newVal)
+			// Suppress warning during test restoration to avoid noise in test output
+			if !shouldSuppressWarning(ctx) {
+				warningMsg := fmt.Sprintf("SetEmulationVersion will change already queried feature:%s from %v to %v", feature, oldVal, newVal)
+				// Try to log to test output first, fallback to global klog
+				if logger := getTestLogger(ctx); logger != nil {
+					logger.Logf("WARNING: %s", warningMsg)
+				} else {
+					klog.Warningf("%s", warningMsg)
+				}
+			}
 		}
 	}
 
@@ -669,6 +684,49 @@ func (f *featureGate) AddMetrics() {
 	}
 }
 
+// contextKey is used to store warning suppression flag in context
+type contextKey struct{}
+
+// testLoggerKey is used to store test logger in context
+type testLoggerKey struct{}
+
+// WithWarningSuppressionContext returns a context with warning suppression flag
+func WithWarningSuppressionContext(ctx context.Context) context.Context {
+	return context.WithValue(ctx, contextKey{}, true)
+}
+
+// WithTestLoggerContext returns a context with test logger for redirecting warnings to test output
+func WithTestLoggerContext(ctx context.Context, logger interface {
+	Logf(format string, args ...interface{})
+}) context.Context {
+	return context.WithValue(ctx, testLoggerKey{}, logger)
+}
+
+// shouldSuppressWarning checks whether warnings should be suppressed
+func shouldSuppressWarning(ctx context.Context) bool {
+	if ctx == nil {
+		return false
+	}
+	suppress, ok := ctx.Value(contextKey{}).(bool)
+	return ok && suppress
+}
+
+// getTestLogger retrieves test logger from context if available
+func getTestLogger(ctx context.Context) interface {
+	Logf(format string, args ...interface{})
+} {
+	if ctx == nil {
+		return nil
+	}
+	logger, ok := ctx.Value(testLoggerKey{}).(interface {
+		Logf(format string, args ...interface{})
+	})
+	if ok {
+		return logger
+	}
+	return nil
+}
+
 // KnownFeatures returns a slice of strings describing the FeatureGate's known features.
 // preAlpha, Deprecated and GA features are hidden from the list.
 func (f *featureGate) KnownFeatures() []string {
diff --git a/staging/src/k8s.io/component-base/featuregate/feature_gate_test.go b/staging/src/k8s.io/component-base/featuregate/feature_gate_test.go
@@ -17,6 +17,7 @@ limitations under the License.
 package featuregate
 
 import (
+	"context"
 	"fmt"
 	"reflect"
 	"sort"
@@ -1905,3 +1906,55 @@ func TestAddVersioned(t *testing.T) {
 		})
 	}
 }
+
+func TestSetEmulationVersionWarningSuppression(t *testing.T) {
+	// Test that warnings are suppressed when using context
+	f := NewVersionedFeatureGate(version.MustParse("1.29"))
+
+	// Add a test feature
+	err := f.AddVersioned(map[Feature]VersionedSpecs{
+		"TestFeature": {
+			{Version: version.MustParse("1.28"), Default: false, PreRelease: Alpha},
+			{Version: version.MustParse("1.29"), Default: true, PreRelease: Beta},
+		},
+	})
+	require.NoError(t, err)
+
+	// Query the feature to mark it as queried
+	_ = f.Enabled("TestFeature")
+
+	// Test 1: Warning should be emitted in normal context
+	err = f.SetEmulationVersion(version.MustParse("1.28"))
+	require.NoError(t, err)
+
+	// Test 2: Warning should be suppressed when using context
+	ctx := WithWarningSuppressionContext(context.Background())
+	err = f.SetEmulationVersionWithContext(ctx, version.MustParse("1.29"))
+	require.NoError(t, err)
+
+	// Test 3: Warning should be emitted again without context
+	err = f.SetEmulationVersion(version.MustParse("1.28"))
+	require.NoError(t, err)
+}
+
+func TestSetEmulationVersionWarningRedirection(t *testing.T) {
+	// Test that warnings can be redirected to test output
+	f := NewVersionedFeatureGate(version.MustParse("1.29"))
+
+	// Add a test feature
+	err := f.AddVersioned(map[Feature]VersionedSpecs{
+		"TestFeature": {
+			{Version: version.MustParse("1.28"), Default: false, PreRelease: Alpha},
+			{Version: version.MustParse("1.29"), Default: true, PreRelease: Beta},
+		},
+	})
+	require.NoError(t, err)
+
+	// Query the feature to mark it as queried
+	_ = f.Enabled("TestFeature")
+
+	// Test: Warning should be redirected to test output instead of global klog
+	ctx := WithTestLoggerContext(context.Background(), t)
+	err = f.SetEmulationVersionWithContext(ctx, version.MustParse("1.28"))
+	require.NoError(t, err)
+}
diff --git a/staging/src/k8s.io/component-base/featuregate/testing/feature_gate.go b/staging/src/k8s.io/component-base/featuregate/testing/feature_gate.go
@@ -17,6 +17,7 @@ limitations under the License.
 package testing
 
 import (
+	"context"
 	"fmt"
 	"strings"
 	"sync"
@@ -130,7 +131,9 @@ func SetFeatureGateEmulationVersionDuringTest(tb TB, gate featuregate.FeatureGat
 	tb.Cleanup(func() {
 		tb.Helper()
 		detectParallelOverrideCleanup()
-		if err := gate.(featuregate.MutableVersionedFeatureGate).SetEmulationVersion(originalEmuVer); err != nil {
+		// Use context to suppress warnings during test cleanup
+		ctx := featuregate.WithWarningSuppressionContext(context.Background())
+		if err := gate.(featuregate.MutableVersionedFeatureGate).SetEmulationVersionWithContext(ctx, originalEmuVer); err != nil {
 			tb.Fatalf("failed to restore emulation version to %s during test", originalEmuVer.String())
 		}
 	})
