copy: avoid deletion error messages when aborting multi-thread copies

When doing a multi-thread copy, handling of the partial upload removal is already done in ChunkWriter.Abort. We can thus avoid doing it on exit in this case, especially as error messages would get generated in most cases (file still being written to or doesn't yet exist)

fs/operations/copy.go

@@ -230,14 +230,6 @@ func (c *copy) updateOrPut(ctx context.Context, in io.ReadCloser, uploadOptions
 
 // Do a manual copy by reading the bytes and writing them
 func (c *copy) manualCopy(ctx context.Context) (actionTaken string, newDst fs.Object, err error) {
-	// Remove partial files on premature exit
-	if !c.inplace {
-		defer atexit.Unregister(atexit.Register(func() {
-			ctx := context.Background()
-			c.removeFailedPartialCopy(ctx, c.f, c.remoteForCopy)
-		}))
-	}
-
 	// Options for the upload
 	uploadOptions := []fs.OpenOption{c.hashOption}
 	for _, option := range c.ci.UploadHeaders {
@@ -253,10 +245,20 @@ func (c *copy) manualCopy(ctx context.Context) (actionTaken string, newDst fs.Ob
 		downloadOptions = append(downloadOptions, option)
 	}
 
+	// Do multi-thread copy if possible
 	if doMultiThreadCopy(ctx, c.f, c.src) {
 		return c.multiThreadCopy(ctx, uploadOptions)
 	}
 
+	// Remove partial files on premature exit
+	// This is not needed for inplace and/or multi-threaded copies
+	if !c.inplace {
+		defer atexit.Unregister(atexit.Register(func() {
+			ctx := context.Background()
+			c.removeFailedPartialCopy(ctx, c.f, c.remoteForCopy)
+		}))
+	}
+
 	var in io.ReadCloser
 	in, err = Open(ctx, c.src, downloadOptions...)
 	if err != nil {