Use BTreeMap instead of a sorted Vec

clap_builder/src/output/help_template.rs

@@ -6,6 +6,7 @@
 // Std
 use std::borrow::Cow;
 use std::cmp;
+use std::collections::BTreeMap;
 
 // Internal
 use crate::builder::PossibleValue;
@@ -467,7 +468,7 @@ impl HelpTemplate<'_, '_> {
         debug!("HelpTemplate::write_args {_category}");
         // The shortest an arg can legally be is 2 (i.e. '-x')
         let mut longest = 2;
-        let mut ord_v = Vec::new();
+        let mut ord_v = BTreeMap::new();
 
         // Determine the longest
         for &arg in args.iter().filter(|arg| {
@@ -486,9 +487,8 @@ impl HelpTemplate<'_, '_> {
             }
 
             let key = (sort_key)(arg);
-            ord_v.push((key, arg));
+            ord_v.insert(key, arg);
         }
-        ord_v.sort_by(|a, b| a.0.cmp(&b.0));
 
         let next_line_help = self.will_args_wrap(args, longest);
 
@@ -858,19 +858,17 @@ impl HelpTemplate<'_, '_> {
         use std::fmt::Write as _;
         let header = &self.styles.get_header();
 
-        let mut ord_v = Vec::new();
+        let mut ord_v = BTreeMap::new();
         for subcommand in cmd
             .get_subcommands()
             .filter(|subcommand| should_show_subcommand(subcommand))
         {
-            ord_v.push((
-                subcommand.get_display_order(),
-                subcommand.get_name(),
+            ord_v.insert(
+                (subcommand.get_display_order(), subcommand.get_name()),
                 subcommand,
-            ));
+            );
         }
-        ord_v.sort_by(|a, b| (a.0, &a.1).cmp(&(b.0, &b.1)));
-        for (_, _, subcommand) in ord_v {
+        for (_, subcommand) in ord_v {
             if !*first {
                 self.writer.push_str("\n\n");
             }
@@ -915,7 +913,7 @@ impl HelpTemplate<'_, '_> {
 
         // The shortest an arg can legally be is 2 (i.e. '-x')
         let mut longest = 2;
-        let mut ord_v = Vec::new();
+        let mut ord_v = BTreeMap::new();
         for subcommand in cmd
             .get_subcommands()
             .filter(|subcommand| should_show_subcommand(subcommand))
@@ -930,19 +928,18 @@ impl HelpTemplate<'_, '_> {
                 let _ = write!(styled, ", {literal}--{long}{literal:#}",);
             }
             longest = longest.max(styled.display_width());
-            ord_v.push((subcommand.get_display_order(), styled, subcommand));
+            ord_v.insert((subcommand.get_display_order(), styled), subcommand);
         }
-        ord_v.sort_by(|a, b| (a.0, &a.1).cmp(&(b.0, &b.1)));
 
         debug!("HelpTemplate::write_subcommands longest = {longest}");
 
         let next_line_help = self.will_subcommands_wrap(cmd.get_subcommands(), longest);
 
-        for (i, (_, sc_str, sc)) in ord_v.into_iter().enumerate() {
+        for (i, (sc_str, sc)) in ord_v.into_iter().enumerate() {
             if 0 < i {
                 self.writer.push_str("\n");
             }
-            self.write_subcommand(sc_str, sc, next_line_help, longest);
+            self.write_subcommand(sc_str.1, sc, next_line_help, longest);
         }
     }