Fix #5302: Create .git/info directory before writing exclude file

When .git/info directory does not exist (can happen with bare clones
or manual deletion), the Exclude function failed with 'no such file
or directory'. Added os.MkdirAll to create the directory before
opening the exclude file.

Added integration test exclude_without_info_dir that removes .git/info
before attempting to exclude a file.

pkg/commands/git_commands/working_tree.go

@@ -246,7 +246,11 @@ func (self *WorkingTreeCommands) Ignore(filename string) error {
 
 // Exclude adds a file to the .git/info/exclude for the repo
 func (self *WorkingTreeCommands) Exclude(filename string) error {
-	excludeFile := filepath.Join(self.repoPaths.repoGitDirPath, "info", "exclude")
+	infoDir := filepath.Join(self.repoPaths.repoGitDirPath, "info")
+	if err := os.MkdirAll(infoDir, 0o755); err != nil {
+		return err
+	}
+	excludeFile := filepath.Join(infoDir, "exclude")
 	return self.os.AppendLineToFile(excludeFile, escapeFilename(filename))
 }
 

pkg/integration/tests/file/exclude_without_info_dir.go

@@ -0,0 +1,32 @@
+package file
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var ExcludeWithoutInfoDir = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Exclude a file when .git/info directory does not exist",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+	},
+	SetupRepo: func(shell *Shell) {
+		// Remove .git/info directory to reproduce #5302
+		shell.RunCommand([]string{"rm", "-rf", ".git/info"})
+		shell.CreateFile("toExclude", "")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Files().
+			IsFocused().
+			Focus().
+			NavigateToLine(Contains("toExclude")).
+			Press(keys.Files.IgnoreFile).
+			Tap(func() {
+				t.ExpectPopup().Menu().Title(Equals("Ignore or exclude file")).Select(Contains("Add to .git/info/exclude")).Confirm()
+
+				// Should succeed without error, creating .git/info/ directory automatically
+				t.FileSystem().FileContent(".git/info/exclude", Contains("/toExclude"))
+			})
+	},
+})

pkg/integration/tests/test_list.go

@@ -221,6 +221,7 @@ var tests = []*components.IntegrationTest{
 	file.DiscardUnstagedRangeSelect,
 	file.DiscardVariousChanges,
 	file.DiscardVariousChangesRangeSelect,
+	file.ExcludeWithoutInfoDir,
 	file.Gitignore,
 	file.GitignoreSpecialCharacters,
 	file.RememberCommitMessageAfterFail,