Validate external core shutdown timeouts

Signed-off-by: Loren Eteval <loren.eteval@proton.me>

Furious/Backends/ExternalCore/Configuration.py

@@ -232,9 +232,14 @@ class ConfigExternalCore(CoreConfiguration):
                 'Shutdown timeout must be a number of seconds'
             )
 
-        value = float(value)
+        try:
+            value = float(value)
+        except OverflowError as ex:
+            raise ExternalCoreConfigurationError(
+                'Shutdown timeout must be between 0.1 and 60 seconds'
+            ) from ex
 
-        if value < 0.1 or value > 60:
+        if not 0.1 <= value <= 60:
             raise ExternalCoreConfigurationError(
                 'Shutdown timeout must be between 0.1 and 60 seconds'
             )

tests/README.md

@@ -91,7 +91,7 @@ worker. Choose tests by the changed contract rather than by filename alone.
 | [test_connection_startup_async.py](test_connection_startup_async.py) | Real local-listener readiness, timeout/cancel/replacement, semantic exits, DNS reply lifetime, mocked platform-specific TUN sequencing. |
 | [test_controllers.py](test_controllers.py) | Connection state/error/reconnect transitions, startup restoration, shared settings, routing fallback persistence and tray/selector agreement after custom-routing disable/re-enable. |
 | [test_runtime_lifecycle.py](test_runtime_lifecycle.py) | Qt-thread exit dispatch, commit/exit races, duplicate and late exits, idempotent release, spawn failure, queue/timer disposal on preparation failure. |
-| [test_external_core.py](test_external_core.py) | Harmless real process launch/output/shutdown, partial thread-start rollback, readiness/TUN metadata, Windows paths with spaces, subscription rejection of executable profiles, bounded DNS references. |
+| [test_external_core.py](test_external_core.py) | Harmless real process launch/output/shutdown, partial thread-start rollback, non-finite timeout rejection, readiness/TUN metadata, Windows paths with spaces, subscription rejection of executable profiles, bounded DNS references. |
 | [test_frozenlib.py](test_frozenlib.py) | Nested state guards, cleanup isolation, bounded caches/throttling, dual-stack probe selection, mocked proxy/DNS/routes/startup/session boundaries and failure handling. |
 | [test_native_tun_semantics.py](test_native_tun_semantics.py) | Xray/Hysteria2 runtime-copy TUN preservation/replacement, managed-TUN failures, download-test stripping, prevention of a second tun2socks owner. |
 | [test_subscription_sync.py](test_subscription_sync.py) | Group-local preparation/commit, stable duplicate identity, atomic failure, preservation of newer local metadata, rejection of changed source state. |

tests/test_external_core.py

@@ -101,6 +101,22 @@ class ExternalCoreProcessTest(unittest.TestCase):
             }
         )
 
+    def testShutdownTimeoutRejectsNonFiniteAndOverflowingValues(self):
+        """Reject invalid wait values before any executable can be acquired."""
+        for value in (float('nan'), float('inf'), -float('inf'), 10**400):
+            with self.subTest(value=str(value)[:20]):
+                config = self.configuration(['-c', 'pass'], str(Path.cwd()))
+                config['shutdownTimeout'] = value
+                self.assertTrue(config.validateProcess())
+                runtime = ExternalCoreProcess(config)
+                with mock.patch(
+                    'Furious.Backends.ExternalCore.Process.subprocess.Popen'
+                ) as spawn:
+                    with self.assertRaises(RuntimeStartError):
+                        runtime.start()
+                    spawn.assert_not_called()
+                runtime.dispose()
+
     def testDisposedRuntimeCannotAcquireAnotherProcess(self):
         """Disposal is terminal even when the stored launch specification is valid."""
         runtime = ExternalCoreProcess(