wayland - ARE YOU IN THERE? (im not angry, im cupping my hands like im speaking into a cave)

src/bin/layers_shell.rs

@@ -37,11 +37,14 @@ fn main() {
 
     #[cfg(all(target_os = "linux", feature = "wayland"))]
     {
-        layers::wayland_shell::run();
-        return;
+        if layers::wayland_shell::try_run() {
+            return;
+        }
+        tracing::warn!(
+            "wayland provider failed to start; falling through to winit so the plugin still loads"
+        );
     }
 
-    #[cfg(not(all(target_os = "linux", feature = "wayland")))]
     if let Err(e) = std::panic::catch_unwind(std::panic::AssertUnwindSafe(run)) {
         tracing::error!("layers shell panicked: {e:?}");
         std::process::exit(1);

src/ffi.rs

@@ -427,7 +427,6 @@ fn finalise_handle(
     let caps = surface.get_capabilities(&adapter);
     let format = caps.formats.first().copied()?;
 
-    // PostMultiplied so the Metal layer's alpha blends against the transparent NSWindow.
     let alpha_mode = if caps
         .alpha_modes
         .contains(&wgpu::CompositeAlphaMode::PostMultiplied)
@@ -445,6 +444,27 @@ fn finalise_handle(
             .unwrap_or(wgpu::CompositeAlphaMode::Auto)
     };
 
+    let adapter_info = adapter.get_info();
+    tracing::info!(
+        backend = ?adapter_info.backend,
+        device_name = %adapter_info.name,
+        format = ?format,
+        all_formats = ?caps.formats,
+        all_alpha_modes = ?caps.alpha_modes,
+        chosen_alpha_mode = ?alpha_mode,
+        "wgpu surface configured"
+    );
+    if matches!(
+        alpha_mode,
+        wgpu::CompositeAlphaMode::Opaque | wgpu::CompositeAlphaMode::Auto
+    ) {
+        tracing::warn!(
+            "wgpu chose {alpha_mode:?} — surface won't be transparent. \
+             X11 needs PreMultiplied/PostMultiplied. Try a different wgpu backend (set WGPU_BACKEND=gl or =vulkan) \
+             or check that the WM has a compositor running."
+        );
+    }
+
     surface.configure(
         &device,
         &wgpu::SurfaceConfiguration {

src/wayland_shell.rs

@@ -33,19 +33,21 @@ const DEFAULT_LOGICAL_SIZE: (u32, u32) = (480, 640);
 const MIN_LOGICAL_SIZE: (u32, u32) = (380, 220);
 const ANCHOR_MARGIN: i32 = 24;
 
-/// Run the Wayland (sctk + wlr-layer-shell) front end. Compiled in only when the
-/// `wayland` feature is enabled — the build script picks the provider based on the
-/// running compositor.
-pub fn run() {
-    tracing::info!("wayland: run entered");
-    let conn = match Connection::connect_to_env() {
-        Ok(c) => {
-            tracing::info!("wayland: Connection::connect_to_env OK");
-            c
-        }
-        Err(e) => {
-            tracing::error!("wayland: connect_to_env failed ({e}); aborting");
-            std::process::exit(1);
+/// Run the Wayland (sctk + wlr-layer-shell) front end. Returns `true` if it took
+/// over the session, `false` if init failed (wayland socket unreachable, no
+/// layer-shell, etc.) so the caller can fall through to the winit path. Hard
+/// exiting here would silently kill the plugin process inside KiCad — which the
+/// user sees as "didn't load."
+pub fn try_run() -> bool {
+    tracing::info!("wayland: try_run entered");
+
+    let conn = match probe_connection() {
+        Some(c) => c,
+        None => {
+            tracing::warn!(
+                "wayland: no reachable compositor socket; falling through to winit"
+            );
+            return false;
         }
     };
 
@@ -55,8 +57,8 @@ pub fn run() {
             pair
         }
         Err(e) => {
-            tracing::error!("wayland: registry init failed ({e}); aborting");
-            std::process::exit(1);
+            tracing::warn!("wayland: registry init failed ({e}); falling through to winit");
+            return false;
         }
     };
     let qh = event_queue.handle();
@@ -69,8 +71,8 @@ pub fn run() {
             c
         }
         Err(e) => {
-            tracing::error!("wayland: wl_compositor missing ({e}); aborting");
-            std::process::exit(1);
+            tracing::warn!("wayland: wl_compositor missing ({e}); falling through to winit");
+            return false;
         }
     };
 
@@ -80,10 +82,10 @@ pub fn run() {
             l
         }
         Err(e) => {
-            tracing::error!(
-                "wayland: zwlr_layer_shell_v1 not advertised ({e}); compositor doesn't support layer-shell. Rebuild with --features x11."
+            tracing::warn!(
+                "wayland: zwlr_layer_shell_v1 not advertised ({e}); falling through to winit"
             );
-            std::process::exit(1);
+            return false;
         }
     };
 
@@ -112,8 +114,8 @@ pub fn run() {
         match NonNull::new(conn.backend().display_ptr() as *mut _) {
             Some(p) => p,
             None => {
-                tracing::error!("wayland: null display ptr");
-                std::process::exit(1);
+                tracing::warn!("wayland: null display ptr; falling through to winit");
+                return false;
             }
         },
     ));
@@ -121,8 +123,8 @@ pub fn run() {
         match NonNull::new(layer.wl_surface().id().as_ptr() as *mut _) {
             Some(p) => p,
             None => {
-                tracing::error!("wayland: null surface ptr");
-                std::process::exit(1);
+                tracing::warn!("wayland: null surface ptr; falling through to winit");
+                return false;
             }
         },
     ));
@@ -153,6 +155,7 @@ pub fn run() {
             break;
         }
     }
+    true
 }
 
 struct State {
@@ -491,6 +494,69 @@ impl PointerHandler for State {
     }
 }
 
+/// Find a wayland socket and connect, regardless of whether `WAYLAND_DISPLAY` is set.
+/// Inside flatpak the env var is often stripped even when the socket itself is bind-
+/// mounted into the sandbox at `$XDG_RUNTIME_DIR/wayland-*`. We list candidates,
+/// log everything we find, and try each in order.
+fn probe_connection() -> Option<Connection> {
+    let runtime_dir = std::env::var_os("XDG_RUNTIME_DIR").map(std::path::PathBuf::from);
+    tracing::info!(
+        xdg_runtime_dir = ?runtime_dir,
+        wayland_display_env = ?std::env::var_os("WAYLAND_DISPLAY"),
+        "wayland: probing for compositor socket"
+    );
+
+    if let Ok(c) = Connection::connect_to_env() {
+        tracing::info!("wayland: connected via $WAYLAND_DISPLAY");
+        return Some(c);
+    }
+
+    let Some(dir) = runtime_dir else {
+        tracing::warn!("wayland: $XDG_RUNTIME_DIR is unset; cannot scan for sockets");
+        return None;
+    };
+
+    let entries = match std::fs::read_dir(&dir) {
+        Ok(e) => e,
+        Err(e) => {
+            tracing::warn!(dir = %dir.display(), "wayland: cannot list runtime dir: {e}");
+            return None;
+        }
+    };
+
+    let mut candidates: Vec<String> = Vec::new();
+    for entry in entries.flatten() {
+        let name = entry.file_name();
+        let Some(name_str) = name.to_str() else { continue; };
+        if !name_str.starts_with("wayland-") {
+            continue;
+        }
+        // Skip lock files; we want the socket itself.
+        if name_str.ends_with(".lock") {
+            continue;
+        }
+        candidates.push(name_str.to_string());
+    }
+    candidates.sort();
+    tracing::info!(?candidates, "wayland: socket candidates in $XDG_RUNTIME_DIR");
+
+    for name in &candidates {
+        // Connection::connect_to_env reads $WAYLAND_DISPLAY; set it for one attempt.
+        std::env::set_var("WAYLAND_DISPLAY", name);
+        match Connection::connect_to_env() {
+            Ok(c) => {
+                tracing::info!(socket = name, "wayland: connected via probed socket");
+                return Some(c);
+            }
+            Err(e) => {
+                tracing::debug!(socket = name, "wayland: probe failed: {e}");
+            }
+        }
+    }
+
+    None
+}
+
 fn log_globals(globals: &GlobalList) {
     let list = globals.contents().clone_list();
     tracing::info!("wayland: registry advertises {} globals", list.len());