fix(rust/gui-client): if we can't raise the tunnel, sign out (#6548)

Refs #6547 

Given a valid token is on disk, when the Client tries to auto-sign-in to
Firezone and something breaks during sign-in, then...

**Old behavior:** ...then the GUI silently implodes and we can't export
logs. When you restart the GUI, it reloads the token and immediately
implodes again.

**New behavior:** ...then the GUI doesn't silently implode, it silently
signs out. Which is still weird, but exporting logs will work.

This addresses an issue where a customer couldn't export logs while
helping us debug #6547.

rust/gui-client/src-tauri/src/client/gui.rs

@@ -538,7 +538,15 @@ impl Controller {
             Req::GetAdvancedSettings(tx) => {
                 tx.send(self.advanced_settings.clone()).ok();
             }
-            Req::Ipc(msg) => self.handle_ipc(msg).await?,
+            Req::Ipc(msg) => match self.handle_ipc(msg).await {
+                Ok(()) => {}
+                // Handles <https://github.com/firezone/firezone/issues/6547> more gracefully so we can still export logs even if we crashed right after sign-in
+                Err(Error::ConnectToFirezoneFailed(error)) => {
+                    tracing::error!(?error, "Failed to connect to Firezone");
+                    self.sign_out().await?;
+                }
+                Err(error) => Err(error)?,
+            }
             Req::IpcReadFailed(error) => {
                 // IPC errors are always fatal
                 tracing::error!(?error, "IPC read failure");
@@ -765,6 +773,8 @@ impl Controller {
                 Ok(())
             }
             Err(IpcServiceError::PortalConnection(error)) => {
+                // This is typically something like, we don't have Internet access so we can't
+                // open the PhoenixChannel's WebSocket.
                 tracing::warn!(
                     ?error,
                     "Failed to connect to Firezone Portal, will try again when the network changes"
@@ -775,12 +785,7 @@ impl Controller {
                 }
                 Ok(())
             }
-            Err(error) => {
-                tracing::error!(?error, "Failed to connect to Firezone");
-                Err(Error::Other(anyhow!(
-                    "Failed to connect to Firezone for non-Portal-related reason"
-                )))
-            }
+            Err(msg) => Err(Error::ConnectToFirezoneFailed(msg)),
         }
     }
 

rust/gui-client/src-tauri/src/client/gui/errors.rs

@@ -1,11 +1,13 @@
 use super::{deep_link, logging};
 use anyhow::Result;
-use firezone_headless_client::{ipc, FIREZONE_GROUP};
+use firezone_headless_client::{ipc, IpcServiceError, FIREZONE_GROUP};
 
 // TODO: Replace with `anyhow` gradually per <https://github.com/firezone/firezone/pull/3546#discussion_r1477114789>
 #[allow(dead_code)]
 #[derive(Debug, thiserror::Error)]
 pub(crate) enum Error {
+    #[error("Failed to connect to Firezone for non-Portal-related reason")]
+    ConnectToFirezoneFailed(IpcServiceError),
     #[error("Deep-link module error: {0}")]
     DeepLink(#[from] deep_link::Error),
     #[error("Logging module error: {0}")]
@@ -39,7 +41,7 @@ pub(crate) fn show_error_dialog(error: &Error) -> Result<()> {
     // This message gets shown to users in the GUI and could be localized, unlike
     // messages in the log which only need to be used for `git grep`.
     let user_friendly_error_msg = match error {
-        // TODO: Update this URL
+        Error::ConnectToFirezoneFailed(_) => error.to_string(),
         Error::WebViewNotInstalled => "Firezone cannot start because WebView2 is not installed. Follow the instructions at <https://www.firezone.dev/kb/client-apps/windows-client>.".to_string(),
         Error::DeepLink(deep_link::Error::CantListen) => "Firezone is already running. If it's not responding, force-stop it.".to_string(),
         Error::DeepLink(deep_link::Error::Other(error)) => error.to_string(),