fix: strict flag values, MI NULL properties and container without HCS (#2553)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

pkg/collector/collection.go

@@ -274,7 +274,10 @@ func (c *Collection) Build(ctx context.Context, logger *slog.Logger) error {
 
 		err := fmt.Errorf("error build collector %s: %w", result.name, result.err)
 
-		if errors.Is(err, pdh.ErrNoData) ||
+		// errors.ErrUnsupported marks a collector whose subsystem is not
+		// available on this host, e.g. a Windows feature that is not installed.
+		if errors.Is(err, errors.ErrUnsupported) ||
+			errors.Is(err, pdh.ErrNoData) ||
 			errors.Is(err, winregistry.ErrNotExist) ||
 			errors.Is(err, pdh.NewPdhError(pdh.CstatusNoObject)) ||
 			errors.Is(err, pdh.NewPdhError(pdh.CstatusNoCounter)) ||

pkg/collector/collection_test.go

@@ -19,6 +19,7 @@ package collector_test
 
 import (
 	"errors"
+	"fmt"
 	"log/slog"
 	"testing"
 	"time"
@@ -69,6 +70,7 @@ func TestCollectionBuildAndClose(t *testing.T) {
 		{name: "success"},
 		{name: "build failure", buildErr: buildFailure, wantBuildErr: buildFailure},
 		{name: "optional counter missing", buildErr: pdh.ErrNoData},
+		{name: "unsupported on this host", buildErr: fmt.Errorf("feature missing: %w", errors.ErrUnsupported)},
 		{name: "close failure", closeErr: closeFailure},
 	} {
 		t.Run(tc.name, func(t *testing.T) {