Use local .gitignore when one exists in the same directory

When ignoring a file, check if a .gitignore already exists in the file's
directory. If so, add just the basename to that local .gitignore instead
of adding the full path to the root .gitignore.

pkg/commands/git_commands/working_tree.go

@@ -239,8 +239,18 @@ func escapeFilename(filename string) string {
 	return re.ReplaceAllString(filename, `\${0}`)
 }
 
-// Ignore adds a file to the gitignore for the repo
+// Ignore adds a file to the gitignore for the repo.
+// If a .gitignore exists in the same directory as the file, it will be used
+// with just the basename. Otherwise, the root .gitignore is used with the full path.
 func (self *WorkingTreeCommands) Ignore(filename string) error {
+	dir := filepath.Dir(filename)
+	if dir != "." {
+		localGitignore := filepath.Join(dir, ".gitignore")
+		if _, err := os.Stat(localGitignore); err == nil {
+			return self.os.AppendLineToFile(localGitignore, escapeFilename(filepath.Base(filename)))
+		}
+	}
+
 	return self.os.AppendLineToFile(".gitignore", escapeFilename(filename))
 }
 

pkg/integration/tests/file/gitignore_local.go

@@ -0,0 +1,58 @@
+package file
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var GitignoreLocal = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Verify that ignoring a file uses the local .gitignore if one exists in the same directory",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+	},
+	SetupRepo: func(shell *Shell) {
+		// Create root .gitignore
+		shell.CreateFile(".gitignore", "")
+		// Create subdirectory with its own .gitignore
+		shell.CreateDir("subdir_with_gitignore")
+		shell.CreateFile("subdir_with_gitignore/.gitignore", "")
+		shell.CreateFile("subdir_with_gitignore/file_to_ignore", "")
+		// Create subdirectory without .gitignore
+		shell.CreateDir("subdir_without_gitignore")
+		shell.CreateFile("subdir_without_gitignore/another_file", "")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Files().
+			IsFocused().
+			Lines(
+				Equals("▼ /").IsSelected(),
+				Equals("  ▼ subdir_with_gitignore"),
+				Equals("    ?? .gitignore"),
+				Equals("    ?? file_to_ignore"),
+				Equals("  ▼ subdir_without_gitignore"),
+				Equals("    ?? another_file"),
+				Equals("  ?? .gitignore"),
+			).
+			// Navigate to subdir_with_gitignore/file_to_ignore
+			NavigateToLine(Contains("file_to_ignore")).
+			Press(keys.Files.IgnoreFile).
+			Tap(func() {
+				t.ExpectPopup().Menu().Title(Equals("Ignore or exclude file")).Select(Contains("Add to .gitignore")).Confirm()
+				// Should be added to the local .gitignore with just the basename
+				t.FileSystem().FileContent("subdir_with_gitignore/.gitignore", Equals("file_to_ignore\n"))
+				// Root .gitignore should remain empty
+				t.FileSystem().FileContent(".gitignore", Equals(""))
+			}).
+			// Navigate to subdir_without_gitignore/another_file
+			NavigateToLine(Contains("another_file")).
+			Press(keys.Files.IgnoreFile).
+			Tap(func() {
+				t.ExpectPopup().Menu().Title(Equals("Ignore or exclude file")).Select(Contains("Add to .gitignore")).Confirm()
+				// Should be added to root .gitignore with full path since no local .gitignore exists
+				t.FileSystem().FileContent(".gitignore", Equals("subdir_without_gitignore/another_file\n"))
+				// Local .gitignore should not have been created
+				t.FileSystem().PathNotPresent("subdir_without_gitignore/.gitignore")
+			})
+	},
+})

pkg/integration/tests/test_list.go

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