Report an error when trying to open ui in linux::headless

crates/gpui/src/app.rs

@@ -502,6 +502,13 @@ impl AppContext {
  })
  }
 
+ /// Returns Ok() if the platform supports opening windows.
+ /// This returns false (for example) on linux when we could
+ /// not establish a connection to X or Wayland.
+ pub fn can_open_windows(&self) -> anyhow::Result<()> {
+ self.platform.can_open_windows()
+ }
+
  /// Instructs the platform to activate the application by bringing it to the foreground.
  pub fn activate(&self, ignoring_other_apps: bool) {
  self.platform.activate(ignoring_other_apps);

crates/gpui/src/platform.rs

@@ -108,6 +108,9 @@ pub(crate) trait Platform: 'static {
  fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>>;
  fn primary_display(&self) -> Option<Rc<dyn PlatformDisplay>>;
  fn active_window(&self) -> Option<AnyWindowHandle>;
+ fn can_open_windows(&self) -> anyhow::Result<()> {
+ Ok(())
+ }
  fn open_window(
  &self,
  handle: AnyWindowHandle,

crates/gpui/src/platform/linux/headless/client.rs

@@ -68,6 +68,10 @@ impl LinuxClient for HeadlessClient {
  None
  }
 
+ fn can_open_windows(&self) -> anyhow::Result<()> {
+ return Err(anyhow::anyhow!("neither DISPLAY, nor WAYLAND_DISPLAY found. You can still run zed for remote development with --dev-server-token."));
+ }
+
  fn open_window(
  &self,
  _handle: AnyWindowHandle,

crates/gpui/src/platform/linux/platform.rs

@@ -55,6 +55,9 @@ pub trait LinuxClient {
  fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>>;
  fn primary_display(&self) -> Option<Rc<dyn PlatformDisplay>>;
  fn display(&self, id: DisplayId) -> Option<Rc<dyn PlatformDisplay>>;
+ fn can_open_windows(&self) -> anyhow::Result<()> {
+ Ok(())
+ }
  fn open_window(
  &self,
  handle: AnyWindowHandle,
@@ -132,6 +135,10 @@ impl<P: LinuxClient + 'static> Platform for P {
  });
  }
 
+ fn can_open_windows(&self) -> anyhow::Result<()> {
+ self.can_open_windows()
+ }
+
  fn quit(&self) {
  self.with_common(|common| common.signal.stop());
  }

crates/zed/src/main.rs

@@ -124,6 +124,10 @@ fn init_ui(app_state: Arc<AppState>, cx: &mut AppContext) -> Result<()> {
  }
  };
 
+ if let Err(err) = cx.can_open_windows() {
+ return Err(err);
+ }
+
  SystemAppearance::init(cx);
  load_embedded_fonts(cx);