Add note on reasoning in optional argument parsing behavior

server/src/cmd.rs

@@ -445,6 +445,18 @@ macro_rules! parse_args {
         {
             let mut args = $args.into_iter().peekable();
             (
+                // We only consume the input argument when parsing is successful. If this fails, we
+                // will then attempt to parse it as the next argument type. This is done regardless
+                // of whether the argument is optional because that information is not available
+                // here. Nevertheless, if the caller only precedes to use the parsed arguments when
+                // all required arguments parse successfully to `Some(val)` this should not create
+                // any unexpected behavior.
+                //
+                // This does mean that optional arguments will be included in the trailing args or
+                // that one optional arg could be interpreted as another, if the user makes a
+                // mistake that causes an optional arg to fail to parse. But there is no way to
+                // discern this in the current model with the optional args and trailing arg being
+                // solely position based.
                 $({
                     let parsed = args.peek().and_then(|s| s.parse::<$t>().ok());
                     // Consume successfully parsed arg.