fs: improve log output when no changes are made - fixes #3454

- changes a few log messages to debug level
- adds a log message for when 0 bytes are transferred

fs/operations/operations.go

@@ -640,7 +640,7 @@ func DeleteFilesWithBackupDir(ctx context.Context, toBeDeleted fs.ObjectsChan, b
 			}
 		}()
 	}
-	fs.Infof(nil, "Waiting for deletions to finish")
+	fs.Debugf(nil, "Waiting for deletions to finish")
 	wg.Wait()
 	if errorCount > 0 {
 		err := errors.Errorf("failed to delete %d files", errorCount)
@@ -872,7 +872,7 @@ func CheckFn(ctx context.Context, fdst, fsrc fs.Fs, check checkFn, oneway bool)
 		Dir:      "",
 		Callback: c,
 	}
-	fs.Infof(fdst, "Waiting for checks to finish")
+	fs.Debugf(fdst, "Waiting for checks to finish")
 	err := m.Run()
 
 	if c.dstFilesMissing > 0 {

fs/sync/sync.go

@@ -345,7 +345,7 @@ func (s *syncCopyMove) startCheckers() {
 // This stops the background checkers
 func (s *syncCopyMove) stopCheckers() {
 	s.toBeChecked.Close()
-	fs.Infof(s.fdst, "Waiting for checks to finish")
+	fs.Debugf(s.fdst, "Waiting for checks to finish")
 	s.checkerWg.Wait()
 }
 
@@ -360,7 +360,7 @@ func (s *syncCopyMove) startTransfers() {
 // This stops the background transfers
 func (s *syncCopyMove) stopTransfers() {
 	s.toBeUploaded.Close()
-	fs.Infof(s.fdst, "Waiting for transfers to finish")
+	fs.Debugf(s.fdst, "Waiting for transfers to finish")
 	s.transfersWg.Wait()
 }
 
@@ -381,7 +381,7 @@ func (s *syncCopyMove) stopRenamers() {
 		return
 	}
 	s.toBeRenamed.Close()
-	fs.Infof(s.fdst, "Waiting for renames to finish")
+	fs.Debugf(s.fdst, "Waiting for renames to finish")
 	s.renamerWg.Wait()
 }
 
@@ -756,6 +756,10 @@ func (s *syncCopyMove) run() error {
 	// Read the error out of the context if there is one
 	s.processError(s.ctx.Err())
 
+	if accounting.Stats(s.ctx).GetTransfers() == 0 {
+		fs.Infof(nil, "There was nothing to transfer")
+	}
+
 	// cancel the context to free resources
 	s.cancel()
 	return s.currentError()