fix: avoid executing actions when completing -- in v2

app_test.go

@@ -1850,6 +1850,36 @@ func TestApp_OrderOfOperations(t *testing.T) {
 	app.Commands = oldCommands
 }
 
+func TestApp_Run_DoubleDashShellCompletionDoesNotExecuteAction(t *testing.T) {
+	origArgv := os.Args
+	t.Cleanup(func() {
+		os.Args = origArgv
+	})
+
+	var output bytes.Buffer
+	actionCalled := false
+
+	app := &App{
+		EnableBashCompletion: true,
+		HideHelp:             true,
+		Writer:               &output,
+		Flags: []Flag{
+			&BoolFlag{Name: "verbose"},
+		},
+		Action: func(c *Context) error {
+			actionCalled = true
+			return nil
+		},
+	}
+
+	os.Args = []string{"command", "--", "--generate-bash-completion"}
+
+	err := app.Run(os.Args)
+	expect(t, err, nil)
+	expect(t, actionCalled, false)
+	expect(t, output.String(), "--verbose\n")
+}
+
 func TestApp_Run_CommandWithSubcommandHasHelpTopic(t *testing.T) {
 	var subcommandHelpTopics = [][]string{
 		{"command", "foo", "--help"},

help.go

@@ -447,12 +447,14 @@ func checkShellCompleteFlag(a *App, arguments []string) (bool, []string) {
 		return false, arguments
 	}
 
-	for _, arg := range arguments {
-		// If arguments include "--", shell completion is disabled
-		// because after "--" only positional arguments are accepted.
-		// https://unix.stackexchange.com/a/11382
+	// If arguments include "--" before the token being completed, shell
+	// completion is disabled because after "--" only positional arguments are
+	// accepted. If "--" is itself the token being completed, keep completion
+	// enabled so long-flag suggestions still work.
+	// https://unix.stackexchange.com/a/11382
+	for i, arg := range arguments[:pos] {
 		if arg == "--" {
-			return false, arguments
+			return i == pos-1, arguments[:pos]
 		}
 	}
 

help_test.go

@@ -1745,7 +1745,16 @@ func Test_checkShellCompleteFlag(t *testing.T) {
 				EnableBashCompletion: true,
 			},
 			wantShellCompletion: false,
-			wantArgs:            []string{"--", "foo", "--generate-bash-completion"},
+			wantArgs:            []string{"--", "foo"},
+		},
+		{
+			name:      "double dash is the token being completed",
+			arguments: []string{"foo", "--", "--generate-bash-completion"},
+			app: &App{
+				EnableBashCompletion: true,
+			},
+			wantShellCompletion: true,
+			wantArgs:            []string{"foo", "--"},
 		},
 		{
 			name:      "--generate-bash-completion",