Move re-rendering the main view after a diff renderer change to a helper

The next commit needs to render the diff again when the terminal
switches between dark and light, with the same care not to replace
whatever else the main view might show.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

pkg/gui/controllers/global_controller.go

@@ -3,7 +3,6 @@ package controllers
 import (
 	"strconv"
 
-	"github.com/jesseduffield/lazygit/pkg/gui/context"
 	"github.com/jesseduffield/lazygit/pkg/gui/types"
 	"github.com/jesseduffield/lazygit/pkg/utils"
 )
@@ -185,13 +184,7 @@ func (self *GlobalController) cycleDiffRenderersBackward() error {
 // onDiffRenderersChanged re-renders the main view so the newly selected diff renderer
 // takes effect, and shows a toast naming it.
 func (self *GlobalController) onDiffRenderersChanged() {
-	currentSide := self.c.Context().CurrentSide()
-	currentKey := self.c.Context().Current().GetKey()
-	if currentSide.GetKey() == currentKey ||
-		currentKey == context.NORMAL_MAIN_CONTEXT_KEY ||
-		currentKey == context.NORMAL_SECONDARY_CONTEXT_KEY {
-		currentSide.HandleRenderToMain()
-	}
+	self.c.Helpers().Diff.RenderToMainAgain()
 
 	diffRendererConfigManager := self.c.State().GetDiffRendererConfigManager()
 	current, total := diffRendererConfigManager.CurrentDiffRendererIndex()

pkg/gui/controllers/helpers/diff_helper.go

@@ -98,6 +98,19 @@ func (self *DiffHelper) ExitDiffMode() error {
 	return nil
 }
 
+// RenderToMainAgain renders the current side panel into the main view again, if
+// that is what the main view shows. This is for when something that the
+// rendering depends on has changed, such as the diff renderer.
+func (self *DiffHelper) RenderToMainAgain() {
+	currentSide := self.c.Context().CurrentSide()
+	currentKey := self.c.Context().Current().GetKey()
+	if currentSide.GetKey() == currentKey ||
+		currentKey == context.NORMAL_MAIN_CONTEXT_KEY ||
+		currentKey == context.NORMAL_SECONDARY_CONTEXT_KEY {
+		currentSide.HandleRenderToMain()
+	}
+}
+
 func (self *DiffHelper) RenderDiff() {
 	args := self.DiffArgs()
 	cmdObj := self.c.Git().Diff.DiffCmdObj(args)