fix: for ISO base disk remove premature return after closing sparse diff file so Convert executes.

Ensure diffDisk is converted to the requested format instead of staying sparse.

Signed-off-by: ashwat287 <ashwatpas@gmail.com>

Author: ashwat287

pkg/driverutil/disk.go

@@ -38,23 +38,21 @@ func EnsureDisk(ctx context.Context, instDir, diskSize string, diskImageFormat i
 	if err != nil {
 		return err
 	}
+	destDisk := baseDisk
 	if isBaseDiskISO {
-		// Create an empty data volume (sparse)
+		destDisk = diffDisk
+		
+		// Create an empty data volume for the diff disk
 		diffDiskF, err := os.Create(diffDisk)
 		if err != nil {
 			return err
 		}
 
-		err = diskUtil.MakeSparse(ctx, diffDiskF, 0)
-		if err != nil {
-			diffDiskF.Close()
-			return fmt.Errorf("failed to create sparse diff disk %q: %w", diffDisk, err)
-		}
-		return diffDiskF.Close()
+		diffDiskF.Close()
 	}
 	// Check whether to use ASIF format
 
-	if err = diskUtil.Convert(ctx, diskImageFormat, baseDisk, diffDisk, &diskSizeInBytes, false); err != nil {
+	if err = diskUtil.Convert(ctx, diskImageFormat, destDisk, diffDisk, &diskSizeInBytes, false); err != nil {
 		return fmt.Errorf("failed to convert %q to a disk %q: %w", baseDisk, diffDisk, err)
 	}
 	return err

pkg/imgutil/nativeimgutil/nativeimgutil.go

@@ -23,10 +23,9 @@ import (
 	"github.com/lima-vm/go-qcow2reader/image/asif"
 	"github.com/lima-vm/go-qcow2reader/image/qcow2"
 	"github.com/lima-vm/go-qcow2reader/image/raw"
-	"github.com/sirupsen/logrus"
-
 	"github.com/lima-vm/lima/v2/pkg/imgutil/nativeimgutil/asifutil"
 	"github.com/lima-vm/lima/v2/pkg/progressbar"
+	"github.com/sirupsen/logrus"
 )
 
 // Disk image size must be aligned to sector size. Qemu block layer is rounding
@@ -62,10 +61,10 @@ func convertTo(destType image.Type, source, dest string, size *int64, allowSourc
 	logrus.Infof("Converting %q (%s) to a %s disk %q", source, srcImg.Type(), destType, dest)
 	switch t := srcImg.Type(); t {
 	case raw.Type:
-		if err = srcF.Close(); err != nil {
-			return err
-		}
 		if destType == raw.Type {
+			if err = srcF.Close(); err != nil {
+				return err
+			}
 			return convertRawToRaw(source, dest, size)
 		}
 	case qcow2.Type: