Fix Files Panel artefacts during rebase commands (#5661)

Several commands (rewording or amending an earlier commit, custom patch
operations, etc.) are implemented by starting an interactive rebase that
stops at a commit, amending it, and continuing. When no conflict occurs,
the user isn't meant to notice a rebase happened at all.

But a background file refresh can fire while the rebase is mid-flight
and render a dirty working copy of whatever the behind-the-scenes rebase
is doing (e.g. applying a custom patch).

To fix this, we pause the background routines for the duration of any
waiting-status operation — exactly the window in which lazygit is
driving the git operation itself and will refresh once at the end. The
boundary is also right for the conflict case: when a rebase stops on a
conflict the operation returns, the pause releases, and background
refreshes resume for the interactive resolution that follows.

pkg/gui/background.go

@@ -3,6 +3,7 @@ package gui
 import (
 	"fmt"
 	"runtime"
+	"sync/atomic"
 	"time"
 
 	"github.com/jesseduffield/lazygit/pkg/gocui"
@@ -13,17 +14,27 @@ import (
 type BackgroundRoutineMgr struct {
 	gui *Gui
 
-	// if we've suspended the gui (e.g. because we've switched to a subprocess)
-	// we typically want to pause some things that are running like background
-	// file refreshes
-	pauseBackgroundRefreshes bool
+	// When this is greater than zero, the background routines (e.g. file refresh)
+	// skip their work. We pause them while the gui is suspended (e.g. for a
+	// subprocess) and while lazygit is itself driving a git operation that would
+	// otherwise be caught mid-flight (see the waiting-status helpers). It's a
+	// count rather than a bool because these pause scopes can overlap.
+	pauseRefreshesCount atomic.Int32
 
 	// a channel to trigger an immediate background fetch; we use this when switching repos
 	triggerFetch chan struct{}
 }
 
 func (self *BackgroundRoutineMgr) PauseBackgroundRefreshes(pause bool) {
-	self.pauseBackgroundRefreshes = pause
+	if pause {
+		self.pauseRefreshesCount.Add(1)
+	} else {
+		self.pauseRefreshesCount.Add(-1)
+	}
+}
+
+func (self *BackgroundRoutineMgr) backgroundRefreshesPaused() bool {
+	return self.pauseRefreshesCount.Load() > 0
 }
 
 func (self *BackgroundRoutineMgr) startBackgroundRoutines() {
@@ -124,7 +135,7 @@ func (self *BackgroundRoutineMgr) goEvery(interval time.Duration, stop chan stru
 		ticker := time.NewTicker(interval)
 		defer ticker.Stop()
 		doit := func(retriggered bool) {
-			if self.pauseBackgroundRefreshes {
+			if self.backgroundRefreshesPaused() {
 				return
 			}
 			self.gui.c.OnWorker(func(gocui.Task) error {

pkg/gui/controllers/helpers/app_status_helper.go

@@ -66,12 +66,22 @@ func (self *AppStatusHelper) WithWaitingStatus(message string, f func(gocui.Task
 }
 
 func (self *AppStatusHelper) WithWaitingStatusImpl(message string, f func(gocui.Task) error, task gocui.Task) error {
+	// A waiting status means lazygit is driving a git operation itself (often
+	// one that internally runs a rebase and continues it). Pause the background
+	// routines for its duration so they don't refresh from an intermediate
+	// state and reveal, say, the half-finished history of a reword.
+	self.c.PauseBackgroundRefreshes(true)
+	defer self.c.PauseBackgroundRefreshes(false)
+
 	return self.statusMgr().WithWaitingStatus(message, self.renderAppStatus, func(waitingStatusHandle *status.WaitingStatusHandle) error {
 		return f(appStatusHelperTask{task, waitingStatusHandle})
 	})
 }
 
 func (self *AppStatusHelper) WithWaitingStatusSync(message string, f func() error) error {
+	self.c.PauseBackgroundRefreshes(true)
+	defer self.c.PauseBackgroundRefreshes(false)
+
 	return self.statusMgr().WithWaitingStatus(message, func() {}, func(*status.WaitingStatusHandle) error {
 		stop := make(chan struct{})
 		defer func() { close(stop) }()

pkg/gui/controllers/helpers/inline_status_helper.go

@@ -68,6 +68,14 @@ func (self *InlineStatusHelper) WithInlineStatus(opts InlineStatusOpts, f func(g
 	visible := view.Visible && self.windowHelper.TopViewInWindow(context.GetWindowName(), false) == view
 	if visible && context.IsItemVisible(opts.Item) {
 		self.c.OnWorker(func(task gocui.Task) error {
+			// An inline status is just a waiting status rendered on the item
+			// rather than in the bottom line, so it gets the same treatment:
+			// pause the background routines while we drive the operation. (The
+			// off-screen branch below goes through WithWaitingStatus, which
+			// already does this.)
+			self.c.PauseBackgroundRefreshes(true)
+			defer self.c.PauseBackgroundRefreshes(false)
+
 			self.start(opts)
 			defer self.stop(opts)
 

pkg/gui/gui_common.go

@@ -50,6 +50,10 @@ func (self *guiCommon) Resume() error {
 	return self.gui.resume()
 }
 
+func (self *guiCommon) PauseBackgroundRefreshes(pause bool) {
+	self.gui.BackgroundRoutineMgr.PauseBackgroundRefreshes(pause)
+}
+
 func (self *guiCommon) Context() types.IContextMgr {
 	return self.gui.State.ContextMgr
 }

pkg/gui/types/common.go

@@ -59,6 +59,10 @@ type IGuiCommon interface {
 	Suspend() error
 	Resume() error
 
+	// Pause or resume the background routines. Calls nest, so every pause must be balanced
+	// by a resume.
+	PauseBackgroundRefreshes(pause bool)
+
 	Context() IContextMgr
 	ContextForKey(key ContextKey) Context