Fix possible crash when deleting a branch while filtering is active

The code that tries to reselect the same branch again uses GetItems, which in
case of filtering is the filtered list. After replacing the branches slice with
a new one, the filtered list is no longer up to date, so we must reapply the
filter before working with it. It so happens that refreshView does that, so
simply call that before setting the selection again; I don't think the order
matters in this case. Otherwise we'd have to insert another call to
ReApplyFilter before the call to GetItems, which we can avoid this way.

Note that this doesn't actually make anything work better in the case of
deleting a branch, since we can't reselect the deleted branch anyway of course.
But it avoids a possible crash if the branch that was deleted was the last one
in the unfiltered list.

pkg/gui/controllers/helpers/refresh_helper.go

@@ -490,6 +490,8 @@ func (self *RefreshHelper) refreshBranches(refreshWorktrees bool, keepBranchSele
 		self.refreshView(self.c.Contexts().Worktrees)
 	}
 
+	self.refreshView(self.c.Contexts().Branches)
+
 	if !keepBranchSelectionIndex && prevSelectedBranch != nil {
 		_, idx, found := lo.FindIndexOf(self.c.Contexts().Branches.GetItems(),
 			func(b *models.Branch) bool { return b.Name == prevSelectedBranch.Name })
@@ -498,8 +500,6 @@ func (self *RefreshHelper) refreshBranches(refreshWorktrees bool, keepBranchSele
 		}
 	}
 
-	self.refreshView(self.c.Contexts().Branches)
-
 	// Need to re-render the commits view because the visualization of local
 	// branch heads might have changed
 	self.c.Mutexes().LocalCommitsMutex.Lock()

pkg/integration/tests/branch/delete_while_filtering.go

@@ -0,0 +1,49 @@
+package branch
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+// Regression test for deleting the last branch in the unfiltered list while
+// filtering is on. This used to cause a segfault.
+var DeleteWhileFiltering = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Delete a local branch while there's a filter in the branches panel",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+		config.GetAppState().LocalBranchSortOrder = "alphabetic"
+	},
+	SetupRepo: func(shell *Shell) {
+		shell.EmptyCommit("one")
+		shell.NewBranch("branch1")
+		shell.NewBranch("branch2")
+		shell.Checkout("master")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Branches().
+			Focus().
+			Lines(
+				Contains("master").IsSelected(),
+				Contains("branch1"),
+				Contains("branch2"),
+			).
+			FilterOrSearch("branch").
+			Lines(
+				Contains("branch1").IsSelected(),
+				Contains("branch2"),
+			).
+			SelectNextItem().
+			Press(keys.Universal.Remove).
+			Tap(func() {
+				t.ExpectPopup().
+					Menu().
+					Title(Equals("Delete branch 'branch2'?")).
+					Select(Contains("Delete local branch")).
+					Confirm()
+			}).
+			Lines(
+				Contains("branch1").IsSelected(),
+			)
+	},
+})

pkg/integration/tests/test_list.go

@@ -45,6 +45,7 @@ var tests = []*components.IntegrationTest{
 	branch.DeleteMultiple,
 	branch.DeleteRemoteBranchWithCredentialPrompt,
 	branch.DeleteRemoteBranchWithDifferentName,
+	branch.DeleteWhileFiltering,
 	branch.DetachedHead,
 	branch.NewBranchAutostash,
 	branch.NewBranchFromRemoteTrackingDifferentName,