From c20badbac326b15a9c2a95d83a0fd07ba796f7dc Mon Sep 17 00:00:00 2001
From: Stefan Haller <stefan@haller-berlin.de>
Date: Tue, 21 Jan 2025 21:00:24 +0100
Subject: [PATCH] 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 |  4 +-
 .../tests/branch/delete_while_filtering.go    | 49 +++++++++++++++++++
 pkg/integration/tests/test_list.go            |  1 +
 3 files changed, 52 insertions(+), 2 deletions(-)
 create mode 100644 pkg/integration/tests/branch/delete_while_filtering.go

diff --git a/pkg/gui/controllers/helpers/refresh_helper.go b/pkg/gui/controllers/helpers/refresh_helper.go
index 46965bddd25..270e552dc5f 100644
--- a/pkg/gui/controllers/helpers/refresh_helper.go
+++ b/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()
diff --git a/pkg/integration/tests/branch/delete_while_filtering.go b/pkg/integration/tests/branch/delete_while_filtering.go
new file mode 100644
index 00000000000..d967ff40fd2
--- /dev/null
+++ b/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(),
+			)
+	},
+})
diff --git a/pkg/integration/tests/test_list.go b/pkg/integration/tests/test_list.go
index c28ab0cdb94..2b909e0d569 100644
--- a/pkg/integration/tests/test_list.go
+++ b/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,