Keep scrolling while commits are dragged at an edge

Reuse the drag autoscroller for commit drags. Scrolling stops once the
insertion point reaches the end of the allowed range in the scroll
direction, so during a rebase the view doesn't keep scrolling once the
last insertion position among the todos has been reached.

pkg/gui/controllers/local_commits_controller.go

@@ -29,8 +29,9 @@ type LocalCommitsController struct {
 	*ListControllerTrait[*models.Commit]
 	c *ControllerCommon
 
-	pullFiles  PullFilesFn
-	commitDrag *commitDragState
+	pullFiles        PullFilesFn
+	commitDrag       *commitDragState
+	dragAutoscroller *helpers.DragAutoscroller
 }
 
 // commitDragState tracks a mouse drag that moves the selected commits. It is
@@ -77,7 +78,7 @@ func NewLocalCommitsController(
 	c *ControllerCommon,
 	pullFiles PullFilesFn,
 ) *LocalCommitsController {
-	return &LocalCommitsController{
+	controller := &LocalCommitsController{
 		baseController: baseController{},
 		c:              c,
 		pullFiles:      pullFiles,
@@ -88,6 +89,13 @@ func NewLocalCommitsController(
 			c.Contexts().LocalCommits.GetSelectedItems,
 		),
 	}
+	controller.dragAutoscroller = helpers.NewDragAutoscroller(
+		c.HelperCommon,
+		c.Contexts().LocalCommits,
+		controller.canCommitDragAutoscroll,
+		controller.handleCommitDragAutoscroll,
+	)
+	return controller
 }
 
 func (self *LocalCommitsController) GetMouseKeybindings(types.KeybindingsOpts) []*gocui.ViewMouseBinding {
@@ -176,13 +184,22 @@ func (self *LocalCommitsController) handleCommitDrag(opts gocui.ViewMouseBinding
 	}
 
 	self.commitDrag.hasMoved = true
+	if self.updateCommitDragInsertion(opts.Y) {
+		self.c.PostRefreshUpdate(self.context())
+	}
+	originY := self.context().GetView().OriginY()
+	self.dragAutoscroller.Update(opts.Y - originY)
 	self.restoreCommitDragHighlight()
-	insertionIndex := self.commitDragInsertionIndex(opts.Y)
+	return nil
+}
+
+func (self *LocalCommitsController) updateCommitDragInsertion(viewIndex int) bool {
+	insertionIndex := self.commitDragInsertionIndex(viewIndex)
 	if insertionIndex >= self.commitDrag.startIndex && insertionIndex <= self.commitDrag.endIndex+1 {
 		insertionIndex = -1
 	}
 	if insertionIndex == self.commitDrag.insertionIndex {
-		return nil
+		return false
 	}
 
 	self.commitDrag.insertionIndex = insertionIndex
@@ -191,8 +208,7 @@ func (self *LocalCommitsController) handleCommitDrag(opts gocui.ViewMouseBinding
 	} else {
 		self.context().SetDropInsertionIndex(insertionIndex)
 	}
-	self.c.PostRefreshUpdate(self.context())
-	return nil
+	return true
 }
 
 // gocui moves the view cursor to the pointer position before invoking our
@@ -235,6 +251,7 @@ func (self *LocalCommitsController) handleCommitDragRelease(gocui.ViewMouseBindi
 	}
 
 	state := self.commitDrag
+	self.dragAutoscroller.Cancel()
 	self.commitDrag = nil
 	self.context().ClearDropInsertionIndex()
 
@@ -312,6 +329,7 @@ func (self *LocalCommitsController) GetOnFocusLost() func(types.OnFocusLostOpts)
 			return
 		}
 
+		self.dragAutoscroller.Cancel()
 		self.commitDrag = nil
 		self.c.GocuiGui().CancelMouseCapture()
 		self.context().ClearDropInsertionIndex()
@@ -319,6 +337,32 @@ func (self *LocalCommitsController) GetOnFocusLost() func(types.OnFocusLostOpts)
 	}
 }
 
+// Stop autoscrolling once the insertion point has reached the end of the
+// allowed range in the scroll direction; e.g. during a rebase there is no
+// point in scrolling on into the section of real commits.
+func (self *LocalCommitsController) canCommitDragAutoscroll(direction int) bool {
+	state := self.commitDrag
+	if state == nil {
+		return false
+	}
+	if direction < 0 {
+		return state.insertionIndex != state.minInsertion
+	}
+	return state.insertionIndex != state.maxInsertion
+}
+
+func (self *LocalCommitsController) handleCommitDragAutoscroll(viewIndex int) bool {
+	if self.commitDrag == nil {
+		return false
+	}
+
+	self.updateCommitDragInsertion(viewIndex)
+	self.context().SetNeedRerenderVisibleLines()
+	self.context().HandleRender()
+	self.restoreCommitDragHighlight()
+	return self.canCommitDragAutoscroll(self.dragAutoscroller.Direction())
+}
+
 func (self *LocalCommitsController) GetKeybindings(opts types.KeybindingsOpts) []*types.Binding {
 	editCommitKey := opts.Config.Universal.Edit
 

pkg/integration/tests/interactive_rebase/drag_to_reorder_with_autoscroll.go

@@ -0,0 +1,35 @@
+package interactive_rebase
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var DragToReorderWithAutoscroll = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Keep scrolling commits while a dragged commit is held at the panel edge",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo: func(shell *Shell) {
+		shell.CreateNCommits(40)
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Commits().
+			Focus().
+			TopLines(
+				Contains("commit-40").IsSelected(),
+			).
+			ClickAndHold(1, 0).
+			MouseMoveToBottom(1).
+			OriginYAtLeast(3).
+			MouseRelease().
+			SelectedLines(
+				Contains("commit-40"),
+			).
+			SelectedLineIdxAtLeast(3).
+			GotoTop().
+			TopLines(
+				Contains("commit-39").IsSelected(),
+			)
+	},
+})

pkg/integration/tests/test_list.go

@@ -293,6 +293,7 @@ var tests = []*components.IntegrationTest{
 	interactive_rebase.DragKeepsSelectionHighlighted,
 	interactive_rebase.DragToReorder,
 	interactive_rebase.DragToReorderInRebase,
+	interactive_rebase.DragToReorderWithAutoscroll,
 	interactive_rebase.DropCommitInCopiedBranchWithUpdateRef,
 	interactive_rebase.DropMergeCommit,
 	interactive_rebase.DropTodoCommitWithUpdateRef,