fix(configurator): allow startup without arguments

Makefile

@@ -83,7 +83,7 @@ help: ## Show the command interface (the default)
 		'  make firmware/boards/kakute-f7-mini-v3' \
 		'  make firmware/boards/kakute-f7-mini-v3 flash' \
 		'  make docs -- build' \
-		'  make firmware/tools/configurator -- --source-system 255 --serial /dev/ttyUSB0 --baud 115200' \
+		'  make firmware/tools/configurator' \
 		'  make firmware/tools/sitl -- move 5 3 1 --wait'
 
 nix-shell: ## Enter the reproducible Nix development shell

firmware/tools/configurator/Makefile

@@ -22,8 +22,8 @@ else
 
 help: ## Show configurator commands
 	@printf '%s\n' 'Configurator' '' \
-		'The root Makefile passes every argument after -- to the application:' \
+		'Start the local web application, then select the serial device in the browser:' \
-		'  make firmware/tools/configurator -- --source-system 255 --serial /dev/ttyUSB0 --baud 115200'
+		'  make firmware/tools/configurator'
 
 endif
 

firmware/tools/configurator/src/main.rs

@@ -6,6 +6,7 @@ use kaptan_configurator::{SerialBaud, SerialController, SharedState, serve_conne
 use kaptan_file_mavlink::Principal;
 
 const LISTEN_ADDRESS: &str = "127.0.0.1:4861";
+const DEFAULT_GCS_SYSTEM_ID: u8 = 255;
 const GCS_COMPONENT_ID: u8 = 190;
 
 fn main() -> std::io::Result<()> {
@@ -81,11 +82,10 @@ fn arguments_from(mut values: impl Iterator<Item = String>) -> std::io::Result<A
             _ => return Err(invalid_arguments(&flag)),
         }
     }
-    let source_system = source_system.ok_or_else(|| invalid_arguments("--source-system"))?;
     Ok(Arguments {
         serial_path,
         baud,
-        source_system,
+        source_system: source_system.unwrap_or(DEFAULT_GCS_SYSTEM_ID),
     })
 }
 
@@ -93,7 +93,7 @@ fn invalid_arguments(flag: &str) -> std::io::Error {
     std::io::Error::new(
         std::io::ErrorKind::InvalidInput,
         format!(
-            "invalid {flag}; usage: kaptan-configurator --source-system ID [--serial PATH] [--baud RATE]"
+            "invalid {flag}; usage: kaptan-configurator [--source-system ID] [--serial PATH] [--baud RATE]"
         ),
     )
 }
@@ -108,7 +108,15 @@ mod tests {
     }
 
     #[test]
-    fn command_line_defaults_to_115200_and_requires_an_exact_source_system() {
+    fn command_line_requires_no_arguments() {
+        let accepted = arguments_from(core::iter::empty()).unwrap();
+        assert_eq!(accepted.serial_path, None);
+        assert_eq!(accepted.baud, SerialBaud::try_new(115_200).unwrap());
+        assert_eq!(accepted.source_system, DEFAULT_GCS_SYSTEM_ID);
+    }
+
+    #[test]
+    fn command_line_accepts_serial_and_source_overrides() {
         let accepted = arguments_from(
             ["--source-system", "255", "--serial", "/dev/ttyACM0"]
                 .into_iter()
@@ -161,7 +169,6 @@ mod tests {
             vec!["--source-system", "255", "--baud"],
             vec!["--source-system", "0"],
             vec!["--source-system", "255", "--source-system", "254"],
-            vec![],
         ] {
             let rejected = arguments_from(values.into_iter().map(String::from))
                 .expect_err("invalid baud arguments must be rejected");