fix(cli): clean error (not traceback) when device is ambiguous in main()

main() resolves the device via setup_environment() before dispatching to the
subcommand, but that call lacked the try/except that do_login/do_logout/do_env
already have -- so "fdp run" (needs_env=True) dumped a raw traceback on a
multi-device ambiguity instead of the helpful "choose a device" message. Wrap
it to print "Error: ..." to stderr and exit(1). Adds a CLI-level regression test.

Author: sammuli

fdp/cli.py

@@ -320,11 +320,20 @@ def main(argv=None) -> None:
     # the FDP env and shouldn't require a device contributor to be
     # installed, so they opt out via `needs_env=False`.
     if getattr(args, "needs_env", True):
-        setup_environment(
-            device=args.default_device,
-            bearer_token=args.bearer_token or None,
-            auto_login=getattr(args, "auto_login", False),
-        )
+        # Device resolution can fail (e.g. no default chosen among several
+        # registered tokamaks); present it as a clean message, not a traceback.
+        try:
+            setup_environment(
+                device=args.default_device,
+                bearer_token=args.bearer_token or None,
+                auto_login=getattr(args, "auto_login", False),
+            )
+        except (ValueError, KeyError) as exc:
+            print(f"Error: {exc}", file=sys.stderr)
+            sys.exit(1)
+        except auth.AuthError as exc:
+            print(f"Login failed: {exc}", file=sys.stderr)
+            sys.exit(1)
 
     args.func(args)
 

tests/test_device_resolution.py

@@ -128,6 +128,22 @@ def test_two_devices_nothing_set_raises_with_all_three_hints(self):
         self.assertIn("FDP_DEFAULT_DEVICE", msg)
         self.assertIn("~/.fdp/config.toml", msg)
 
+    def test_fdp_run_multidevice_exits_cleanly_not_traceback(self):
+        # `fdp run` resolves the device in main() before dispatching; a
+        # multi-device ambiguity must surface as a clean Error + exit(1),
+        # not an uncaught traceback.
+        import io
+        import contextlib
+        from fdp import cli
+        stderr = io.StringIO()
+        with self.assertRaises(SystemExit) as ctx, \
+                contextlib.redirect_stderr(stderr):
+            cli.main(["run", "true"])
+        self.assertEqual(ctx.exception.code, 1)
+        err = stderr.getvalue()
+        self.assertIn("Error:", err)
+        self.assertIn("--default-device", err)
+
     def test_env_var_selects_device(self):
         from fdp.environment import _resolve_device_handle
         os.environ["FDP_DEFAULT_DEVICE"] = "mast"