Revert "Hold the placeholder until first paint when restoring a scroll position"

This reverts the holdViewLines flicker patch (Race A). It is about to be
superseded by rendering a re-render into an off-screen buffer and swapping
it in atomically, which keeps the displayed buffer (and so every reader)
untouched until the new content is ready — a cleaner mechanism than
suppressing the view-line rebuild. Removing it on its own keeps that
upcoming change focused.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

pkg/gocui/view.go

@@ -110,21 +110,6 @@ type View struct {
 	// ignore them; this is the count of the entries they may trust.
 	freshViewLineCount int
 
-	// While true, refreshViewLinesIfNeeded leaves the current view lines in
-	// place instead of rebuilding them from the (changing) buffer, so the view
-	// keeps drawing the previous render in full. This is a stronger form of the
-	// viewLines retention described above: rather than revealing new content
-	// line-by-line as it loads, it holds the *whole* previous render until told
-	// to release. It is used when re-rendering content the view is already
-	// scrolled into (escaping to a focused main view): the placeholder left in
-	// the view is held, coherent, at its scroll until the re-render task's first
-	// paint scrolls to the saved position and releases the hold, swapping to the
-	// loaded content in one step — so a layout pass landing mid-load can't draw
-	// half-loaded content at the not-yet-restored scroll. While held, the view
-	// lines are a placeholder that need not match the buffer, so the
-	// view-line→buffer-line mapping reports no result.
-	holdViewLines bool
-
 	// writeMutex protects locks the write process
 	writeMutex sync.Mutex
 
@@ -1254,18 +1239,6 @@ func (v *View) FlushStaleCells() {
 	v.clearViewLines()
 }
 
-// SetHoldViewLines controls whether refreshViewLinesIfNeeded holds the current
-// view lines instead of rebuilding them from the buffer (see holdViewLines). A
-// re-render task sets it while restoring a scroll position and releases it at
-// its first paint, so the view keeps showing the coherent placeholder until the
-// loaded content is shown at the restored scroll in one step.
-func (v *View) SetHoldViewLines(hold bool) {
-	v.writeMutex.Lock()
-	defer v.writeMutex.Unlock()
-
-	v.holdViewLines = hold
-}
-
 func (v *View) rewind() {
 	v.buf.ei.reset()
 	v.buf.ei.resetScreenCursor()
@@ -1487,10 +1460,6 @@ func (v *View) refreshViewLinesIfNeeded() {
 		return
 	}
 
-	if v.holdViewLines {
-		return
-	}
-
 	maxX := v.InnerWidth()
 	wrap := 0
 	if v.Wrap {
@@ -1785,13 +1754,6 @@ func (v *View) BufferLineForViewLine(y int) (int, bool) {
 func (v *View) bufferLineForViewLine(y int) (int, bool) {
 	v.refreshViewLinesIfNeeded()
 
-	// While holding the previous render (see holdViewLines), the displayed view
-	// lines are a placeholder that need not correspond to the loading buffer, so
-	// there is no valid mapping to return.
-	if v.holdViewLines {
-		return 0, false
-	}
-
 	// Bound on freshViewLineCount rather than len(v.viewLines): the entries past
 	// it are a stale tail retained for flicker-avoidance (see freshViewLineCount)
 	// and don't correspond to the current buffer. Within the fresh range every

pkg/gocui/view_test.go

@@ -233,36 +233,6 @@ func TestBufferLineForViewLineStaleTail(t *testing.T) {
 	assert.False(t, ok)
 }
 
-// While holding the view lines, the view keeps drawing the previous render even
-// as the buffer is overwritten, so a re-render that is restoring a scroll
-// position can keep showing the coherent placeholder until its first paint
-// reveals the loaded content in one step. See View.holdViewLines.
-func TestHoldViewLines(t *testing.T) {
-	v := NewView("name", 0, 0, 80, 10, OutputNormal)
-
-	v.writeString("a\nb\nc")
-	assert.Equal(t, []string{"a", "b", "c"}, v.ViewBufferLines())
-
-	v.SetHoldViewLines(true)
-
-	// Re-render the flicker-avoidance way (rewind, then overwrite from the top).
-	v.Reset()
-	v.writeString("w\nx\ny\nz")
-
-	// The new content is in the buffer, but while held the view keeps showing the
-	// previous render, and the view-line→buffer-line mapping reports no result.
-	assert.Equal(t, []string{"a", "b", "c"}, v.ViewBufferLines())
-	_, ok := v.BufferLineForViewLine(0)
-	assert.False(t, ok)
-
-	// Releasing the hold reveals the loaded content.
-	v.SetHoldViewLines(false)
-	assert.Equal(t, []string{"w", "x", "y", "z"}, v.ViewBufferLines())
-	bufferLine, ok := v.BufferLineForViewLine(0)
-	assert.True(t, ok)
-	assert.Equal(t, 0, bufferLine)
-}
-
 func TestContainsColoredText(t *testing.T) {
 	hexColor := func(text string, hexStr string) []cell {
 		cells := make([]cell, len(text))

pkg/gui/pty.go

@@ -83,14 +83,6 @@ func (gui *Gui) newPtyTask(view *gocui.View, cmd *exec.Cmd, prefix string) error
 	// its first paint.
 	targetOriginY := gui.getManager(view).GetScrollToOriginYForNextTask()
 
-	// While restoring a scroll position, hold the placeholder currently in the
-	// view until the first paint (released by ApplyInitialScroll), so a layout
-	// pass landing mid-load can't draw half-loaded content at the not-yet-restored
-	// scroll. Set synchronously here (before the layout pass that drains
-	// afterLayout) for the same reason StartLoading is. A render without a scroll
-	// to restore clears any leftover hold.
-	view.SetHoldViewLines(targetOriginY != nil)
-
 	// Run the pty after layout so that it gets the correct size
 	gui.afterLayout(func() error {
 		// Need to get the width and the pager command again because the layout might have

pkg/gui/tasks_adapter.go

@@ -35,13 +35,6 @@ func (gui *Gui) newCmdTask(view *gocui.View, cmd *exec.Cmd, prefix string) error
 	// The task clears the request and suppresses the origin reset when it starts.
 	targetOriginY := manager.GetScrollToOriginYForNextTask()
 
-	// While restoring a scroll position, hold the placeholder currently in the
-	// view until the first paint, so a layout pass landing mid-load can't draw
-	// half-loaded content at the not-yet-restored scroll. Released by the first
-	// paint (ApplyInitialScroll). A render without a scroll to restore clears any
-	// leftover hold so its content reveals normally.
-	view.SetHoldViewLines(targetOriginY != nil)
-
 	var r io.ReadCloser
 	start := func() (tasks.Cmd, io.Reader) {
 		view.SetContentWidth(contentWidth)

pkg/gui/view_helpers.go

@@ -33,10 +33,6 @@ func (gui *Gui) linesToReadFromCmdTask(v *gocui.View, targetOriginY *int) tasks.
 		oy = *targetOriginY
 		applyInitialScroll = func() {
 			v.SetOrigin(v.OriginX(), *targetOriginY)
-			// Release the placeholder hold (set when this scroll-restore task
-			// started): the next refresh now reveals the loaded content at the
-			// restored scroll in one step. See View.holdViewLines.
-			v.SetHoldViewLines(false)
 		}
 	}