Add test that shows problems with git-ignoring files with special characters

For #, !, [, and ], the problem is that it doesn't ignore the file because the
special characters need to be quoted. For *, the problem is that it ignores too
much (it also hides the abc_def file because the * is treated as a glob).

pkg/integration/tests/file/gitignore_special_characters.go

@@ -0,0 +1,87 @@
+package file
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var GitignoreSpecialCharacters = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Ignore files with special characters in their names",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig: func(config *config.AppConfig) {
+	},
+	SetupRepo: func(shell *Shell) {
+		shell.CreateFile(".gitignore", "")
+		shell.CreateFile("#file", "")
+		shell.CreateFile("file#abc", "")
+		shell.CreateFile("!file", "")
+		shell.CreateFile("file!abc", "")
+		shell.CreateFile("abc*def", "")
+		shell.CreateFile("abc_def", "")
+		shell.CreateFile("file[x]", "")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		excludeFile := func(fileName string) {
+			t.Views().Files().
+				NavigateToLine(Contains(fileName)).
+				Press(keys.Files.IgnoreFile)
+
+			t.ExpectPopup().Menu().
+				Title(Equals("Ignore or exclude file")).
+				Select(Contains("Add to .gitignore")).
+				Confirm()
+		}
+
+		t.Views().Files().
+			Focus().
+			Lines(
+				Equals("▼ /"),
+				Equals("  ?? !file"),
+				Equals("  ?? #file"),
+				Equals("  ?? .gitignore"),
+				Equals("  ?? abc*def"),
+				Equals("  ?? abc_def"),
+				Equals("  ?? file!abc"),
+				Equals("  ?? file#abc"),
+				Equals("  ?? file[x]"),
+			)
+
+		excludeFile("#file")
+		excludeFile("file#abc")
+		excludeFile("!file")
+		excludeFile("file!abc")
+		excludeFile("abc*def")
+		excludeFile("file[x]")
+
+		t.Views().Files().
+			/* EXPECTED:
+			Lines(
+				Equals("▼ /"),
+				Equals("  ?? .gitignore"),
+				Equals("  ?? abc_def"),
+			)
+			ACTUAL:
+			  As you can see, it did ignore the 'file!abc' and 'file#abc' files
+			  correctly. Those don't need to be quoted because # and ! are only
+			  special at the beginning.
+
+			  Most of the other files are not ignored properly because their
+			  special characters need to be escaped. For * it's the other way
+			  round: while it does hide 'abc*def', it also hides 'abc_def',
+			  which we don't want.
+			*/
+			Lines(
+				Equals("▼ /"),
+				Equals("  ?? !file"),
+				Equals("  ?? #file"),
+				Equals("  ?? .gitignore"),
+				Equals("  ?? file[x]"),
+			)
+
+		/* EXPECTED:
+		t.FileSystem().FileContent(".gitignore", Equals("\\#file\nfile#abc\n\\!file\nfile!abc\nabc\\*def\nfile\\[x\\]\n"))
+		ACTUAL: */
+		t.FileSystem().FileContent(".gitignore", Equals("#file\nfile#abc\n!file\nfile!abc\nabc*def\nfile[x]\n"))
+	},
+})

pkg/integration/tests/test_list.go

@@ -197,6 +197,7 @@ var tests = []*components.IntegrationTest{
 	file.DiscardVariousChanges,
 	file.DiscardVariousChangesRangeSelect,
 	file.Gitignore,
+	file.GitignoreSpecialCharacters,
 	file.RememberCommitMessageAfterFail,
 	file.RenameSimilarityThresholdChange,
 	file.RenamedFiles,