fix: generate UKI only if actually needed

Without this fix, imager tries to generate UKI when it's not needed at
all, and also it might try to generate UKI when it's not even supported
for the version of Talos.

Signed-off-by: Andrey Smirnov <andrey.smirnov@siderolabs.com>

pkg/imager/imager.go

@@ -103,8 +103,25 @@ func (i *Imager) Execute(ctx context.Context, outputPath string, report *reporte
 		Status:  reporter.StatusSucceeded,
 	})
 
-	// 4. Build UKI unless the output is a kernel or cmdline.
-	if i.prof.Output.Kind != profile.OutKindKernel && i.prof.Output.Kind != profile.OutKindCmdline {
+	// 4. Build UKI if needed
+	needBuildUKI := quirks.New(i.prof.Version).SupportsUKI()
+
+	switch i.prof.Output.Kind {
+	case profile.OutKindUKI:
+		if !needBuildUKI {
+			return "", fmt.Errorf("UKI output is not supported in this Talos version")
+		}
+	case profile.OutKindISO, profile.OutKindImage, profile.OutKindInstaller:
+		needBuildUKI = needBuildUKI && i.prof.SecureBootEnabled()
+	case profile.OutKindCmdline, profile.OutKindKernel, profile.OutKindInitramfs:
+		needBuildUKI = false
+	case profile.OutKindUnknown:
+		fallthrough
+	default:
+		return "", fmt.Errorf("unknown output kind: %s", i.prof.Output.Kind)
+	}
+
+	if needBuildUKI {
 		if err = i.buildUKI(ctx, report); err != nil {
 			return "", err
 		}

pkg/machinery/imager/quirks/quirks.go

@@ -27,13 +27,13 @@ func New(talosVersion string) Quirks {
 	}}
 }
 
-var minVersionResetOption = semver.MustParse("1.4.0")
-
 // Version returns the Talos version.
 func (q Quirks) Version() *semver.Version {
 	return q.v
 }
 
+var minVersionResetOption = semver.MustParse("1.4.0")
+
 // SupportsResetGRUBOption returns true if the Talos version supports the reset option in GRUB menu (image and ISO).
 func (q Quirks) SupportsResetGRUBOption() bool {
 	// if the version doesn't parse, we assume it's latest Talos
@@ -44,6 +44,18 @@ func (q Quirks) SupportsResetGRUBOption() bool {
 	return q.v.GTE(minVersionResetOption)
 }
 
+var minVersionUKI = semver.MustParse("1.5.0")
+
+// SupportsUKI returns true if the Talos version supports building UKIs.
+func (q Quirks) SupportsUKI() bool {
+	// if the version doesn't parse, we assume it's latest Talos
+	if q.v == nil {
+		return true
+	}
+
+	return q.v.GTE(minVersionUKI)
+}
+
 var minVersionCompressedMETA = semver.MustParse("1.6.3")
 
 // SupportsCompressedEncodedMETA returns true if the Talos version supports compressed and encoded META as an environment variable.