Suppress the initial update in plain display mode

src/output/interactive_display.go

@@ -24,6 +24,7 @@ type displayer interface {
 	Update(targets []buildingTarget)
 	Close()
 	Frequency() time.Duration
+	ShowInitialUpdate() bool
 }
 
 func setupDisplayer(state *core.BuildState, progress Progress, plain bool) displayer {
@@ -81,6 +82,10 @@ func (d *plainDisplay) Frequency() time.Duration {
 
 func (d *plainDisplay) Close() {}
 
+func (d *plainDisplay) ShowInitialUpdate() bool {
+	return false
+}
+
 type interactiveDisplay struct {
 	state                                               *core.BuildState
 	progress                                            Progress
@@ -102,6 +107,10 @@ func (d *interactiveDisplay) Frequency() time.Duration {
 	return 50 * time.Millisecond
 }
 
+func (d *interactiveDisplay) ShowInitialUpdate() bool {
+	return true
+}
+
 func (d *interactiveDisplay) Update(targets []buildingTarget) {
 	d.maxRows, d.maxCols = cli.CurrentBackend.MaxDimensions()
 	d.moveToFirstLine()

src/output/shell_output.go

@@ -51,7 +51,9 @@ func MonitorState(state *core.BuildState, progress Progress, results <-chan *cor
 	t := time.NewTicker(displayer.Frequency())
 	defer t.Stop()
 	bt := newBuildingTargets(state, progress, plainOutput)
-	displayer.Update(bt.Targets())
+	if displayer.ShowInitialUpdate() {
+		displayer.Update(bt.Targets())
+	}
 loop:
 	for {
 		select {