Bugfix for default value UI when there's no help description

clap_builder/src/output/help_template.rs

@@ -657,12 +657,15 @@ impl HelpTemplate<'_, '_> {
         help.indent("", &trailing_indent);
         self.writer.push_styled(&help);
 
+        let mut has_possible_values = false;
         if let Some(arg) = arg {
             if !arg.is_hide_possible_values_set() && self.use_long_pv(arg) {
                 const DASH_SPACE: usize = "- ".len();
                 let possible_vals = arg.get_possible_values();
                 if !possible_vals.is_empty() {
                     debug!("HelpTemplate::help: Found possible vals...{possible_vals:?}");
+                    has_possible_values = true;
+
                     let longest = possible_vals
                         .iter()
                         .filter(|f| !f.is_hide_set())
@@ -709,7 +712,7 @@ impl HelpTemplate<'_, '_> {
 
         if !spec_vals.is_empty() && next_line_specs {
             let mut help = StyledStr::new();
-            if !help_is_empty {
+            if !help_is_empty || has_possible_values {
                 let sep = "\n\n";
                 help.push_str(sep);
             }

tests/builder/help.rs

@@ -3107,6 +3107,41 @@ fn too_many_value_names_panics() {
         .debug_assert();
 }
 
+#[test]
+fn help_enum_arg_with_no_description() {
+    let cmd = Command::new("test").arg(
+        Arg::new("config")
+            .action(ArgAction::Set)
+            // .help("No help description for this argument")
+            .short('c')
+            .long("config")
+            .value_name("MODE")
+            .value_parser([
+                PossibleValue::new("fast"),
+                PossibleValue::new("slow").help("slower than fast"),
+                PossibleValue::new("secret speed").hide(true),
+            ])
+            .default_value("fast"),
+    );
+
+    let expected = str![[r#"
+Usage: test [OPTIONS]
+
+Options:
+  -c, --config <MODE>
+          Possible values:
+          - fast
+          - slow: slower than fast
+
+          [default: fast]
+
+  -h, --help
+          Print help (see a summary with '-h')
+
+"#]];
+    utils::assert_output(cmd, "test --help", expected, false);
+}
+
 #[test]
 fn disabled_help_flag() {
     let res = Command::new("foo")