Stop mouse wheel from leaking escape characters into form fields

Scrolling the mouse wheel while a title or description field was focused
could insert stray characters (fragments of SGR mouse escape sequences)
into the field. The submit TUI ran the Bubble Tea program with
WithMouseAllMotion (mode 1003), which reports an event on every pointer
move. During a wheel scroll that floods the input stream, and under that
volume Bubble Tea can split a mouse escape sequence across input reads;
the leftover bytes of a partially-parsed sequence are then emitted as
key runes and inserted into the focused text input.

Switch to WithMouseCellMotion (mode 1002), which reports clicks, drag,
and wheel but not idle pointer motion. That removes the input flood, so
wheel sequences arrive intact and are parsed as mouse messages (consumed
by handleMouse) instead of leaking as text. The TUI never used idle-hover
state for rendering, so cell-motion loses nothing.

Add a regression test asserting that wheel events over either panel never
modify the focused title or description field.

Author: skarim

cmd/submit.go

@@ -289,7 +289,12 @@ func collectPRDrafts(cfg *config.Config, client github.ClientOps, s *stack.Stack
 		Version:   Version,
 	})
 
-	p := tea.NewProgram(model, tea.WithAltScreen(), tea.WithMouseAllMotion())
+	// Use cell-motion mouse mode (clicks, drag, and wheel) rather than all-motion.
+	// All-motion (mode 1003) reports an event on every pointer move, flooding the
+	// input; under that volume bubbletea can split an SGR mouse sequence across
+	// reads, leaking its bytes as text into a focused title/description field
+	// while scrolling. We don't use idle-hover, so cell-motion loses nothing.
+	p := tea.NewProgram(model, tea.WithAltScreen(), tea.WithMouseCellMotion())
 	final, err := p.Run()
 	if err != nil {
 		return nil, false, fmt.Errorf("running submit TUI: %w", err)

internal/tui/submitview/screen_test.go

@@ -605,6 +605,47 @@ func TestMouse_WheelScrollsDescriptionViewport(t *testing.T) {
 	assert.False(t, m.descScrollPinned, "typing returns to the cursor-following view")
 }
 
+// TestMouse_WheelDoesNotEnterFieldText guards against the regression where
+// scrolling the mouse wheel leaked escape-sequence bytes as text into the
+// focused title/description field. handleMouse must consume every wheel event
+// (returning without forwarding it to the text inputs), so the field contents
+// never change regardless of which panel the pointer is over.
+func TestMouse_WheelDoesNotEnterFieldText(t *testing.T) {
+	m := testModel(t, newNodes())
+	require.Equal(t, fieldTitle, m.focusedField)
+
+	leftW, _ := m.panelWidths()
+	leftX := leftW / 2  // over the left timeline
+	rightX := leftW + 5 // over the right editor
+	titleLine, _, _, _, _ := m.rightZones()
+	y := m.panelTopRow() + titleLine
+
+	wheel := func(m Model) Model {
+		t.Helper()
+		for _, x := range []int{leftX, rightX} {
+			for _, b := range []tea.MouseButton{tea.MouseButtonWheelUp, tea.MouseButtonWheelDown} {
+				u, _ := m.Update(tea.MouseMsg{Action: tea.MouseActionPress, Button: b, X: x, Y: y})
+				m = u.(Model)
+			}
+		}
+		return m
+	}
+
+	// Title focused: wheeling over either panel must not alter the title.
+	titleBefore := m.nodes[m.cursor].Title
+	m = wheel(m)
+	assert.Equal(t, titleBefore, m.nodes[m.cursor].Title, "wheel must not modify the focused title")
+	assert.Equal(t, titleBefore, m.titleInput.Value(), "wheel must not modify the title input")
+
+	// Description focused: same guarantee.
+	m = sendKey(t, m, tea.KeyMsg{Type: tea.KeyTab})
+	require.Equal(t, fieldDescription, m.focusedField)
+	descBefore := m.nodes[m.cursor].Description
+	m = wheel(m)
+	assert.Equal(t, descBefore, m.nodes[m.cursor].Description, "wheel must not modify the focused description")
+	assert.Equal(t, descBefore, m.descArea.Value(), "wheel must not modify the description input")
+}
+
 func TestMouse_WheelScrollBoundedByContent(t *testing.T) {
 	// The over-scroll bug only appears with a real color profile (the textarea
 	// pads blank rows with styled spaces), so force one here.