feat(help): add short to help output

argh/tests/subcommand_short_help.rs

@@ -0,0 +1,73 @@
+use argh::FromArgs;
+
+#[derive(FromArgs, PartialEq, Debug)]
+/// Top-level command.
+struct TopLevel {
+    #[argh(subcommand)]
+    nested: MySubCommandEnum,
+}
+
+#[derive(FromArgs, PartialEq, Debug)]
+#[argh(subcommand)]
+enum MySubCommandEnum {
+    One(SubCommandOne),
+    Two(SubCommandTwo),
+}
+
+#[derive(FromArgs, PartialEq, Debug)]
+/// First subcommand.
+#[argh(subcommand, name = "one", short = 'o')]
+struct SubCommandOne {
+    #[argh(switch)]
+    /// fooey
+    fooey: bool,
+}
+
+#[derive(FromArgs, PartialEq, Debug)]
+/// Second subcommand.
+#[argh(subcommand, name = "two")]
+struct SubCommandTwo {
+    #[argh(switch)]
+    /// bar
+    bar: bool,
+}
+
+#[test]
+fn test_subcommand_short_help() {
+    let early_exit = TopLevel::from_args(&["cmd"], &["help"]).unwrap_err();
+    let output = early_exit.output;
+
+    // Check that 'one' has its short name 'o'
+    assert!(output.contains("one  o"), "Help output should contain 'one  o'");
+    // Check that 'two' does NOT have a short name (it should just be 'two')
+    assert!(output.contains("two "), "Help output should contain 'two '");
+    assert!(!output.contains("two  t"), "Help output should NOT contain 'two  t'");
+
+    let expected_part = "  one  o            First subcommand.
+  two               Second subcommand.";
+    assert!(
+        output.contains(expected_part),
+        "Help output did not match expected subcommand list formatting. Got:
+{}",
+        output
+    );
+}
+
+#[test]
+fn test_subcommand_short_help_own() {
+    // Invoke via full name
+    let early_exit_full = TopLevel::from_args(&["cmd"], &["one", "help"]).unwrap_err();
+    assert!(
+        early_exit_full.output.contains("Usage: cmd one [--fooey]"),
+        "Usage should be 'cmd one ...'"
+    );
+
+    // Invoke via short name
+    let early_exit_short = TopLevel::from_args(&["cmd"], &["o", "help"]).unwrap_err();
+    assert!(
+        early_exit_short.output.contains("Usage: cmd one [--fooey]"),
+        "Usage should still be 'cmd one ...' even if 'o' was used"
+    );
+
+    assert_eq!(early_exit_full.output, early_exit_short.output);
+}

argh_shared/src/lib.rs

@@ -164,6 +164,10 @@ pub fn write_description(out: &mut String, cmd: &CommandInfo<'_>) {
     let mut current_line = INDENT.to_string();
     current_line.push_str(cmd.name);
 
+    if *cmd.short != '\0' {
+        current_line.push_str(&format!("  {}", cmd.short));
+    }
+
     if cmd.description.is_empty() {
         new_line(&mut current_line, out);
         return;