blueprint: extract unmarshalTOMLviaJSON() helper

pkg/blueprint/filesystem_customizations.go

@@ -19,23 +19,6 @@ type filesystemCustomizationMarshaling struct {
 	MinSize    datasizes.Size `json:"minsize,omitempty" toml:"minsize,omitempty"`
 }
 
-func (fsc *FilesystemCustomization) UnmarshalTOML(data any) error {
-	// This is the most efficient way to reuse code when unmarshaling
-	// structs in toml, it leaks json errors which is a bit sad but
-	// because the toml unmarshaler gives us not "[]byte" but an
-	// already pre-processed "any" we cannot just unmarshal into our
-	// "fooMarshaling" struct and reuse the result so we resort to
-	// this workaround (but toml will go away long term anyway).
-	dataJSON, err := json.Marshal(data)
-	if err != nil {
-		return fmt.Errorf("error unmarshaling TOML data %v: %w", data, err)
-	}
-	if err := fsc.UnmarshalJSON(dataJSON); err != nil {
-		return fmt.Errorf("error decoding TOML %v: %w", data, err)
-	}
-	return nil
-}
-
 func (fsc *FilesystemCustomization) UnmarshalJSON(data []byte) error {
 	var fc filesystemCustomizationMarshaling
 	if err := json.Unmarshal(data, &fc); err != nil {
@@ -50,6 +33,10 @@ func (fsc *FilesystemCustomization) UnmarshalJSON(data []byte) error {
 	return nil
 }
 
+func (fsc *FilesystemCustomization) UnmarshalTOML(data any) error {
+	return unmarshalTOMLviaJSON(fsc, data)
+}
+
 // CheckMountpointsPolicy checks if the mountpoints are allowed by the policy
 func CheckMountpointsPolicy(mountpoints []FilesystemCustomization, mountpointAllowList *pathpolicy.PathPolicies) error {
 	var errs []error

pkg/blueprint/toml_json_bridge.go

@@ -0,0 +1,24 @@
+package blueprint
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// XXX: move to interal/common ?
+func unmarshalTOMLviaJSON(u json.Unmarshaler, data any) error {
+	// This is the most efficient way to reuse code when unmarshaling
+	// structs in toml, it leaks json errors which is a bit sad but
+	// because the toml unmarshaler gives us not "[]byte" but an
+	// already pre-processed "any" we cannot just unmarshal into our
+	// "fooMarshaling" struct and reuse the result so we resort to
+	// this workaround (but toml will go away long term anyway).
+	dataJSON, err := json.Marshal(data)
+	if err != nil {
+		return fmt.Errorf("error unmarshaling TOML data %v: %w", data, err)
+	}
+	if err := u.UnmarshalJSON(dataJSON); err != nil {
+		return fmt.Errorf("error decoding TOML %v: %w", data, err)
+	}
+	return nil
+}