fix(macos): preserve DNS and proxy state across network changes

src-tauri/src/core/proxy_control.rs

@@ -180,6 +180,14 @@ pub const fn is_missing_network_service(_error: &sysproxy::Error) -> bool {
     false
 }
 
+pub fn is_missing_network_service_failure(error: &anyhow::Error) -> bool {
+    !SystemProxyStateUnknown::is_in(error)
+        && SysproxyFailure::from_chain(error).is_none()
+        && error
+            .downcast_ref::<sysproxy::Error>()
+            .is_some_and(is_missing_network_service)
+}
+
 /// Distinguish a misplaced sidecar from a missing privileged service.
 async fn classify_local_apply_failure(error: anyhow::Error) -> anyhow::Error {
     if SysproxyFailure::from_chain(&error).is_some() || !was_refused_locally(&error) {
@@ -359,6 +367,13 @@ fn service_apply_result(requested: &MacosProxyConfig, outcome: ProxyApplyOutcome
         ProxyApplyOutcome::Applied | ProxyApplyOutcome::NotRequested => Ok(()),
         // Direct fallback satisfies a disable request.
         ProxyApplyOutcome::DirectFallback { .. } if matches!(requested, MacosProxyConfig::Disabled) => Ok(()),
+        // Older helpers encode a failed service lookup as fallback even when no OS write occurred.
+        #[cfg(target_os = "macos")]
+        ProxyApplyOutcome::DirectFallback { message }
+            if message == sysproxy::Error::NoActiveNetworkService.to_string() =>
+        {
+            Err(sysproxy::Error::NoActiveNetworkService.into())
+        }
         ProxyApplyOutcome::DirectFallback { message } => {
             Err(SysproxyFailure::DirectFallback { detail: message }.into())
         }
@@ -609,6 +624,10 @@ pub async fn refresh_guard() -> Result<()> {
                     logging!(debug, Type::Core, "proxy guard superseded (generation {generation})");
                     break;
                 }
+                Err(error) if is_missing_network_service_failure(&error) => {
+                    consecutive_failures = 0;
+                    logging!(debug, Type::Core, "system proxy guard waits for a network service");
+                }
                 Err(error) => {
                     consecutive_failures += 1;
                     logging!(
@@ -1110,10 +1129,11 @@ mod tests {
         .err()
         .unwrap_or_else(|| anyhow::anyhow!("an enable that never reached the OS must fail"));
 
-        assert_eq!(
-            SysproxyFailure::from_chain(&error).map(SysproxyFailure::code),
-            Some("SYSPROXY_DIRECT_FALLBACK")
-        );
+        assert!(super::is_missing_network_service_failure(&error));
+        assert!(SysproxyFailure::from_chain(&error).is_none());
+        assert!(!super::is_missing_network_service_failure(
+            &error.context(SystemProxyStateUnknown)
+        ));
     }
 
     #[cfg(target_os = "macos")]