Open file diffs in the focused main view

Enter and double-click should take users to the diff where line actions now
live, whether the file belongs to the working tree or a commit. Share the
existing focus, raw-fallback, and selection setup while retaining directory,
submodule, and conflict-specific behavior.

Co-Authored-By: GitHub Copilot <copilot@github.com>

pkg/gui/controllers/commits_files_controller.go

@@ -557,40 +557,15 @@ func (self *CommitFilesController) currentFromToReverseForPatchBuilding() (strin
 }
 
 func (self *CommitFilesController) enter(node *filetree.CommitFileNode) error {
-	return self.enterCommitFile(node, types.OnFocusOpts{ClickedWindowName: "", ClickedViewLineIdx: -1})
-}
-
-func (self *CommitFilesController) enterCommitFile(node *filetree.CommitFileNode, opts types.OnFocusOpts) error {
 	if node.File == nil {
 		return self.handleToggleCommitFileDirCollapsed(node)
 	}
 
-	if self.c.UserConfig().Git.DiffContextSize == 0 {
-		return fmt.Errorf(self.c.Tr.Actions.NotEnoughContextForCustomPatch,
-			self.c.UserConfig().Keybinding.Universal.IncreaseContextInDiffView)
-	}
+	return focusMainView(self.c, self.context(), -1)
+}
 
-	from, to, reverse := self.currentFromToReverseForPatchBuilding()
-	mustDiscardPatch := self.c.Git().Patch.PatchBuilder.Active() && self.c.Git().Patch.PatchBuilder.NewPatchRequired(from, to, reverse)
-	return self.c.ConfirmIf(mustDiscardPatch, types.ConfirmOpts{
-		Title:  self.c.Tr.DiscardPatch,
-		Prompt: self.c.Tr.DiscardPatchConfirm,
-		HandleConfirm: func() error {
-			if mustDiscardPatch {
-				self.c.Git().Patch.PatchBuilder.Reset()
-			}
-
-			if !self.c.Git().Patch.PatchBuilder.Active() {
-				if err := self.startPatchBuilder(); err != nil {
-					return err
-				}
-			}
-
-			self.c.Context().Push(self.c.Contexts().CustomPatchBuilder, opts)
-
-			return nil
-		},
-	})
+func (self *CommitFilesController) GetOnDoubleClick() func() error {
+	return self.withItemGraceful(self.enter)
 }
 
 func (self *CommitFilesController) handleToggleCommitFileDirCollapsed(node *filetree.CommitFileNode) error {

pkg/gui/controllers/files_controller.go

@@ -415,9 +415,7 @@ func (self *FilesController) GetFocusedMainViewDiffSource() types.FocusedMainVie
 }
 
 func (self *FilesController) GetOnDoubleClick() func() error {
-	return self.withItemGraceful(func(node *filetree.FileNode) error {
-		return self.press([]*filetree.FileNode{node})
-	})
+	return self.enter
 }
 
 // if we are dealing with a status for which there is no key in this map,
@@ -694,7 +692,7 @@ func (self *FilesController) getSelectedFile() *models.File {
 }
 
 func (self *FilesController) enter() error {
-	return self.EnterFile(types.OnFocusOpts{ClickedWindowName: "", ClickedViewLineIdx: -1})
+	return self.enterFile(-1)
 }
 
 func (self *FilesController) collapseAll() error {
@@ -713,7 +711,10 @@ func (self *FilesController) expandAll() error {
 	return nil
 }
 
-func (self *FilesController) EnterFile(opts types.OnFocusOpts) error {
+// enterFile focuses the diff of the selected file, which is where the commands that
+// act on its lines live. clickedViewLineIdx is the row of the diff a click landed on,
+// or -1 when the diff wasn't clicked.
+func (self *FilesController) enterFile(clickedViewLineIdx int) error {
 	node := self.context().GetSelected()
 	if node == nil {
 		return nil
@@ -739,10 +740,7 @@ func (self *FilesController) EnterFile(opts types.OnFocusOpts) error {
 		return self.switchToMerge()
 	}
 
-	context := lo.Ternary(opts.ClickedWindowName == "secondary", self.c.Contexts().StagingSecondary, self.c.Contexts().Staging)
-	self.c.Context().Push(context, opts)
-
-	return nil
+	return focusMainView(self.c, self.context(), clickedViewLineIdx)
 }
 
 // conflictResolutionHint formats a conflict description for the main view,
@@ -1533,7 +1531,7 @@ func (self *FilesController) handleStashSave(stashFunc func(message string) erro
 }
 
 func (self *FilesController) onClickMain(opts gocui.ViewMouseBindingOpts) error {
-	return self.EnterFile(types.OnFocusOpts{ClickedWindowName: "main", ClickedViewLineIdx: opts.Y})
+	return self.enterFile(opts.Y)
 }
 
 func (self *FilesController) fetch() error {

pkg/gui/controllers/switch_to_focused_main_view_controller.go

@@ -71,20 +71,28 @@ func (self *SwitchToFocusedMainViewController) onClickSecondary(opts gocui.ViewM
 }
 
 func (self *SwitchToFocusedMainViewController) handleFocusMainView() error {
+	return focusMainView(self.c, self.context, -1)
+}
+
+func focusMainView(c *ControllerCommon, source types.Context, clickedLineIdx int) error {
 	// Usually the main pane, but the content can be in the secondary one alone: a file
 	// with nothing but staged changes shows them there.
-	mainViewContext := self.c.Contexts().Normal
-	if self.c.State().GetRepoState().GetMainPanes() == types.SecondaryPaneOnly {
-		mainViewContext = self.c.Contexts().NormalSecondary
+	mainViewContext := c.Contexts().Normal
+	if c.State().GetRepoState().GetMainPanes() == types.SecondaryPaneOnly {
+		mainViewContext = c.Contexts().NormalSecondary
 	}
-	return self.focusMainView(mainViewContext, -1)
+	return focusMainViewPane(c, source, mainViewContext, clickedLineIdx)
 }
 
 func (self *SwitchToFocusedMainViewController) focusMainView(mainViewContext *context.MainContext, clickedLineIdx int) error {
-	mainViewContext.ClearSearchString()
-	self.c.Context().Push(mainViewContext, types.OnFocusOpts{})
+	return focusMainViewPane(self.c, self.context, mainViewContext, clickedLineIdx)
+}
 
-	if _, ok := self.context.(types.DiffMainViewContext); !ok {
+func focusMainViewPane(c *ControllerCommon, source types.Context, mainViewContext *context.MainContext, clickedLineIdx int) error {
+	mainViewContext.ClearSearchString()
+	c.Context().Push(mainViewContext, types.OnFocusOpts{})
+
+	if _, ok := source.(types.DiffMainViewContext); !ok {
 		return nil
 	}
 
@@ -93,13 +101,13 @@ func (self *SwitchToFocusedMainViewController) focusMainView(mainViewContext *co
 	// is. Now that the user wants to act on it, it is re-rendered as git's own diff — the
 	// panel below decides that for itself, from the same question — and the selection
 	// goes on that instead of on rows we can't place.
-	if self.c.Helpers().DiffLine.MainViewDiffMode() == git_commands.DiffModeRaw {
-		self.c.Helpers().DiffLine.RenderFocusedMainViewAgain(mainViewContext.GetView(), self.context, func() {
-			self.c.Helpers().DiffLine.EstablishSelection(mainViewContext, clickedLineIdx)
+	if c.Helpers().DiffLine.MainViewDiffMode() == git_commands.DiffModeRaw {
+		c.Helpers().DiffLine.RenderFocusedMainViewAgain(mainViewContext.GetView(), source, func() {
+			c.Helpers().DiffLine.EstablishSelection(mainViewContext, clickedLineIdx)
 		})
 		return nil
 	}
 
-	self.c.Helpers().DiffLine.EstablishSelection(mainViewContext, clickedLineIdx)
+	c.Helpers().DiffLine.EstablishSelection(mainViewContext, clickedLineIdx)
 	return nil
 }

pkg/integration/tests/commit/discard_old_file_changes.go

@@ -131,7 +131,7 @@ var DiscardOldFileChanges = NewIntegrationTest(NewIntegrationTestArgs{
 				Equals("    A file2ToRemove"),
 			).
 			NavigateToLine(Contains("multiLineFile")).
-			Press(keys.Universal.FocusMainView)
+			PressEnter()
 
 		t.Views().Main().
 			IsFocused().

pkg/integration/tests/demo/custom_patch.go

@@ -52,7 +52,7 @@ var CustomPatch = NewIntegrationTest(NewIntegrationTestArgs{
 					IsFocused().
 					NavigateToLine(Contains("users.go")).
 					Wait(1000).
-					Press(keys.Universal.FocusMainView).
+					PressEnter().
 					Tap(func() {
 						t.Views().Main().
 							IsFocused().

pkg/integration/tests/demo/stage_lines.go

@@ -56,7 +56,7 @@ var StageLines = NewIntegrationTest(NewIntegrationTestArgs{
 
 		t.Views().Files().
 			IsFocused().
-			Press(keys.Universal.FocusMainView)
+			PressEnter()
 
 		t.Views().Main().
 			IsFocused().

pkg/integration/tests/main_view/enter_and_double_click_focus_file_diff.go

@@ -0,0 +1,69 @@
+package main_view
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var EnterAndDoubleClickFocusFileDiff = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Enter and double-click focus a file's diff in the main view",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+		config.GetUserConfig().Gui.UseHunkModeInStagingView = false
+	},
+	SetupRepo: func(shell *Shell) {
+		shell.CreateFileAndAdd("file1", "base\n")
+		shell.Commit("add file")
+		shell.UpdateFile("file1", "changed\n")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Files().
+			IsFocused().
+			Lines(
+				Contains("file1").IsSelected(),
+			).
+			PressEnter()
+
+		t.Views().Main().
+			IsFocused().
+			SelectedLines(Contains("-base")).
+			PressEscape()
+
+		t.Views().Files().
+			IsFocused().
+			Click(3, 0).
+			Click(3, 0)
+		t.Views().Main().
+			IsFocused().
+			SelectedLines(Contains("-base")).
+			PressEscape()
+
+		t.Views().Commits().
+			Focus().
+			Lines(
+				Contains("add file").IsSelected(),
+			).
+			PressEnter()
+
+		t.Views().CommitFiles().
+			IsFocused().
+			Lines(
+				Contains("file1").IsSelected(),
+			).
+			PressEnter()
+
+		t.Views().Main().
+			IsFocused().
+			SelectedLines(Contains("+base")).
+			PressEscape()
+
+		t.Views().CommitFiles().
+			IsFocused().
+			Click(3, 0).
+			Click(3, 0)
+		t.Views().Main().
+			IsFocused().
+			SelectedLines(Contains("+base"))
+	},
+})

pkg/integration/tests/test_list.go

@@ -392,6 +392,7 @@ var tests = []*components.IntegrationTest{
 	main_view.EditHistoricalDiffLine,
 	main_view.EditHunkInFocusedDiff,
 	main_view.EditSelectedDiffLine,
+	main_view.EnterAndDoubleClickFocusFileDiff,
 	main_view.EscapeDismissesSelection,
 	main_view.FileNavigationScrollsToTheTop,
 	main_view.FocusFollowsAPaneEmptiedFromOutside,