fs: Implement --no-update-dir-modtime to disable setting modification times on dirs

docs/content/docs.md

@@ -1809,6 +1809,11 @@ files if they are incorrect as it would normally.
 This can be used if the remote is being synced with another tool also
 (e.g. the Google Drive client).
 
+### --no-update-dir-modtime ###
+
+When using this flag, rclone won't update modification times of remote
+directories if they are incorrect as it would normally.
+
 ### --order-by string ###
 
 The `--order-by` flag controls the order in which files in the backlog

fs/config.go

@@ -89,6 +89,7 @@ type ConfigInfo struct {
 	NoCheckDest                bool
 	NoUnicodeNormalization     bool
 	NoUpdateModTime            bool
+	NoUpdateDirModTime         bool
 	DataRateUnit               string
 	CompareDest                []string
 	CopyDest                   []string

fs/config/configflags/configflags.go

@@ -91,6 +91,7 @@ func AddFlags(ci *fs.ConfigInfo, flagSet *pflag.FlagSet) {
 	flags.BoolVarP(flagSet, &ci.NoCheckDest, "no-check-dest", "", ci.NoCheckDest, "Don't check the destination, copy regardless", "Copy")
 	flags.BoolVarP(flagSet, &ci.NoUnicodeNormalization, "no-unicode-normalization", "", ci.NoUnicodeNormalization, "Don't normalize unicode characters in filenames", "Config")
 	flags.BoolVarP(flagSet, &ci.NoUpdateModTime, "no-update-modtime", "", ci.NoUpdateModTime, "Don't update destination modtime if files identical", "Copy")
+	flags.BoolVarP(flagSet, &ci.NoUpdateDirModTime, "no-update-dir-modtime", "", ci.NoUpdateModTime, "Don't update directory modification times", "Copy")
 	flags.StringArrayVarP(flagSet, &ci.CompareDest, "compare-dest", "", nil, "Include additional comma separated server-side paths during comparison", "Copy")
 	flags.StringArrayVarP(flagSet, &ci.CopyDest, "copy-dest", "", nil, "Implies --compare-dest but also copies files from paths into destination", "Copy")
 	flags.StringVarP(flagSet, &ci.BackupDir, "backup-dir", "", ci.BackupDir, "Make backups into hierarchy based in DIR", "Sync")

fs/operations/operations.go

@@ -2612,6 +2612,11 @@ func CopyDirMetadata(ctx context.Context, f fs.Fs, dst fs.Directory, dir string,
 // It does not create the directory.
 func SetDirModTime(ctx context.Context, f fs.Fs, dst fs.Directory, dir string, modTime time.Time) (newDst fs.Directory, err error) {
 	logName := dirName(f, dst, dir)
+	ci := fs.GetConfig(ctx)
+	if ci.NoUpdateDirModTime {
+		fs.Debugf(logName, "Skipping set directory modification time as --no-update-dir-modtime is set")
+		return nil, nil
+	}
 	if SkipDestructive(ctx, logName, "set directory modification time") {
 		return nil, nil
 	}

fs/operations/operations_test.go

@@ -1755,14 +1755,21 @@ func TestCopyDirMetadata(t *testing.T) {
 
 func TestSetDirModTime(t *testing.T) {
 	const name = "set modtime on existing directory"
-	ctx := context.Background()
+	ctx, ci := fs.AddConfig(context.Background())
 	r := fstest.NewRun(t)
 	if r.Fremote.Features().DirSetModTime == nil && !r.Fremote.Features().WriteDirSetModTime {
 		t.Skip("Skipping test as remote does not support DirSetModTime or WriteDirSetModTime")
 	}
 
-	// First try with the directory not existing - should return an error
+	// Check that we obey --no-update-dir-modtime - this should return nil, nil
+	ci.NoUpdateDirModTime = true
 	newDst, err := operations.SetDirModTime(ctx, r.Fremote, nil, "set modtime on non existent directory", t2)
+	require.NoError(t, err)
+	require.Nil(t, newDst)
+	ci.NoUpdateDirModTime = false
+
+	// First try with the directory not existing - should return an error
+	newDst, err = operations.SetDirModTime(ctx, r.Fremote, nil, "set modtime on non existent directory", t2)
 	require.Error(t, err)
 	require.Nil(t, newDst)
 

fs/sync/sync.go

@@ -154,8 +154,8 @@ func newSyncCopyMove(ctx context.Context, fdst, fsrc fs.Fs, deleteMode fs.Delete
 		trackRenamesCh:         make(chan fs.Object, ci.Checkers),
 		checkFirst:             ci.CheckFirst,
 		setDirMetadata:         ci.Metadata && fsrc.Features().ReadDirMetadata && fdst.Features().WriteDirMetadata,
-		setDirModTime:          fdst.Features().WriteDirSetModTime || fdst.Features().MkdirMetadata != nil || fdst.Features().DirSetModTime != nil,
-		setDirModTimeAfter:     fdst.Features().DirModTimeUpdatesOnWrite,
+		setDirModTime:          !ci.NoUpdateDirModTime && (fdst.Features().WriteDirSetModTime || fdst.Features().MkdirMetadata != nil || fdst.Features().DirSetModTime != nil),
+		setDirModTimeAfter:     !ci.NoUpdateDirModTime && fdst.Features().DirModTimeUpdatesOnWrite,
 		modifiedDirs:           make(map[string]struct{}),
 	}
 

fs/sync/sync_test.go

@@ -344,6 +344,45 @@ func TestMoveEmptyDirectories(t *testing.T) {
 	fstest.CheckDirModTime(ctx, t, r.Fremote, got, subDirT)
 }
 
+// Test that --no-update-dir-modtime is working
+func TestSyncNoUpdateDirModtime(t *testing.T) {
+	r := fstest.NewRun(t)
+	if r.Fremote.Features().DirSetModTime == nil {
+		t.Skip("Skipping test as backend does not support DirSetModTime")
+	}
+
+	ctx, ci := fs.AddConfig(context.Background())
+	ci.NoUpdateDirModTime = true
+	const name = "sub dir no update dir modtime"
+
+	// Set the modtime on name to something specific
+	_, err := operations.MkdirModTime(ctx, r.Flocal, name, t1)
+	require.NoError(t, err)
+
+	// Create the remote directory with the current time
+	require.NoError(t, r.Fremote.Mkdir(ctx, name))
+
+	// Read its modification time
+	wantT := fstest.NewDirectory(ctx, t, r.Fremote, name).ModTime(ctx)
+
+	ctx = predictDstFromLogger(ctx)
+	err = Sync(ctx, r.Fremote, r.Flocal, true)
+	require.NoError(t, err)
+	testLoggerVsLsf(ctx, r.Fremote, operations.GetLoggerOpt(ctx).JSON, t)
+
+	r.CheckRemoteListing(
+		t,
+		[]fstest.Item{},
+		[]string{
+			name,
+		},
+	)
+
+	// Read the new directory modification time - it should not have changed
+	gotT := fstest.NewDirectory(ctx, t, r.Fremote, name).ModTime(ctx)
+	fstest.AssertTimeEqualWithPrecision(t, name, wantT, gotT, r.Fremote.Precision())
+}
+
 // Test sync empty directories
 func TestSyncEmptyDirectories(t *testing.T) {
 	ctx := context.Background()