manifest: use local variables for OSCustomizations

Writing directly to OSCustomizations is not a good idea. Use local variables
instead.

This patch refactors Subscription, WSL and Firstboot customizations all
at once since this is the pattern that is common to all of them.

Author: lzap

pkg/manifest/os.go

@@ -544,6 +544,8 @@ func (p *OS) serialize() (osbuild.Pipeline, error) {
 		return osbuild.Pipeline{}, err
 	}
 
+	var subscriptionEnabledServices []string
+
 	if p.ostreeParentSpec != nil {
 		pipeline.AddStage(osbuild.NewOSTreePasswdStage("org.osbuild.source", p.ostreeParentSpec.Checksum))
 	}
@@ -694,22 +696,16 @@ func (p *OS) serialize() (osbuild.Pipeline, error) {
 		p.addStagesForAllFilesAndInlineData(&pipeline, fbFiles)
 	}
 
-	if len(fbCerts) > 0 {
-		p.OSCustomizations.CACerts = append(p.OSCustomizations.CACerts, fbCerts...)
-	}
-
-	if fbUnit != nil {
-		p.OSCustomizations.EnabledServices = append(p.OSCustomizations.EnabledServices, fbUnit.Filename)
-		p.OSCustomizations.SystemdUnit = append(p.OSCustomizations.SystemdUnit, fbUnit)
-	}
-
 	for _, systemdUnitConfig := range p.OSCustomizations.SystemdDropin {
 		pipeline.AddStage(osbuild.NewSystemdUnitStage(systemdUnitConfig))
 	}
 
 	for _, systemdUnitCreateConfig := range p.OSCustomizations.SystemdUnit {
 		pipeline.AddStage(osbuild.NewSystemdUnitCreateStage(systemdUnitCreateConfig))
 	}
+	if fbUnit != nil {
+		pipeline.AddStage(osbuild.NewSystemdUnitCreateStage(fbUnit))
+	}
 
 	if p.OSCustomizations.Authselect != nil {
 		pipeline.AddStage(osbuild.NewAuthselectStage(p.OSCustomizations.Authselect))
@@ -789,7 +785,7 @@ func (p *OS) serialize() (osbuild.Pipeline, error) {
 		pipeline.AddStage(subStage)
 		pipeline.AddStages(osbuild.GenDirectoryNodesStages(subDirs)...)
 		p.addStagesForAllFilesAndInlineData(&pipeline, subFiles)
-		p.OSCustomizations.EnabledServices = append(p.OSCustomizations.EnabledServices, subServices...)
+		subscriptionEnabledServices = subServices
 	}
 
 	if p.OSCustomizations.RHSMConfig != nil {
@@ -930,6 +926,10 @@ func (p *OS) serialize() (osbuild.Pipeline, error) {
 	disabledServices := []string{}
 	maskedServices := []string{}
 	enabledServices = append(enabledServices, p.OSCustomizations.EnabledServices...)
+	if fbUnit != nil {
+		enabledServices = append(enabledServices, fbUnit.Filename)
+	}
+	enabledServices = append(enabledServices, subscriptionEnabledServices...)
 	disabledServices = append(disabledServices, p.OSCustomizations.DisabledServices...)
 	maskedServices = append(maskedServices, p.OSCustomizations.MaskedServices...)
 	if p.Environment != nil {
@@ -955,14 +955,13 @@ func (p *OS) serialize() (osbuild.Pipeline, error) {
 	}
 
 	if p.OSCustomizations.WSLDistributionConfig != nil {
-		// We format in our version string into the name field, if there's no %s in there nothing
-		// special will happen.
-		p.OSCustomizations.WSLDistributionConfig.OOBE.DefaultName = fmt.Sprintf(
-			p.OSCustomizations.WSLDistributionConfig.OOBE.DefaultName,
+		// Format version into the name field; if there's no %s nothing special happens.
+		wslDistConfig := *p.OSCustomizations.WSLDistributionConfig
+		wslDistConfig.OOBE.DefaultName = fmt.Sprintf(
+			wslDistConfig.OOBE.DefaultName,
 			p.OSVersion,
 		)
-
-		pipeline.AddStage(osbuild.NewWSLDistributionConfStage(p.OSCustomizations.WSLDistributionConfig))
+		pipeline.AddStage(osbuild.NewWSLDistributionConfStage(&wslDistConfig))
 	}
 
 	if p.OSCustomizations.FIPS {
@@ -988,8 +987,10 @@ func (p *OS) serialize() (osbuild.Pipeline, error) {
 		}))
 	}
 
-	if len(p.OSCustomizations.CACerts) > 0 {
-		for _, cc := range p.OSCustomizations.CACerts {
+	allCACerts := append([]string{}, p.OSCustomizations.CACerts...)
+	allCACerts = append(allCACerts, fbCerts...)
+	if len(allCACerts) > 0 {
+		for _, cc := range allCACerts {
 			files, err := osbuild.NewCAFileNodes(cc)
 			if err != nil {
 				return osbuild.Pipeline{}, err