fix(opener): avoid blocking-runtime panic in reveal_item_in_dir (#3565)

* fix(opener): avoid blocking-runtime panic in reveal_item_in_dir

* fix(opener): run zbus reveal on a dedicated thread for all callers

Move the runtime-panic fix into the Linux/BSD implementation so the
public Rust APIs are covered too, not just the JS command, and propagate
the spawn_blocking join error via the existing Tauri error variant.

---------

Co-authored-by: Lucas Nogueira <lucas@tauri.app>

.changes/fix-opener-reveal-item-in-dir-blocking-panic.md

@@ -0,0 +1,6 @@
+---
+"opener": "patch"
+"opener-js": "patch"
+---
+
+Fixed `revealItemInDir` and the `reveal_item_in_dir` / `reveal_items_in_dir` Rust APIs panicking on Linux and the BSDs with `Cannot start a runtime from within a runtime` when zbus is built with its `tokio` feature and the call happens inside an async runtime. The blocking D-Bus calls now run on a dedicated thread.

plugins/opener/src/commands.rs

@@ -72,5 +72,6 @@ pub async fn open_path<R: Runtime>(
 /// TODO: in the next major version, rename to `reveal_items_in_dir`
 #[tauri::command]
 pub async fn reveal_item_in_dir(paths: Vec<PathBuf>) -> crate::Result<()> {
-    crate::reveal_items_in_dir(&paths)
+    // `reveal_items_in_dir` blocks on D-Bus / shell calls, so keep it off the async runtime workers.
+    tauri::async_runtime::spawn_blocking(move || crate::reveal_items_in_dir(&paths)).await?
 }

plugins/opener/src/reveal_item_in_dir.rs

@@ -213,6 +213,17 @@ mod imp {
     use std::path::PathBuf;
 
     pub fn reveal_items_in_dir(paths: &[PathBuf]) -> crate::Result<()> {
+        // `zbus::blocking` starts its own tokio runtime when zbus is built with the `tokio` feature,
+        // which panics with "Cannot start a runtime from within a runtime" if the caller is already
+        // inside one (e.g. an async command), so always run it on a dedicated thread.
+        std::thread::scope(|s| {
+            s.spawn(|| reveal_items_in_dir_blocking(paths))
+                .join()
+                .unwrap_or_else(|e| std::panic::resume_unwind(e))
+        })
+    }
+
+    fn reveal_items_in_dir_blocking(paths: &[PathBuf]) -> crate::Result<()> {
         let connection = zbus::blocking::Connection::session()?;
 
         reveal_with_filemanager1(paths, &connection).or_else(|e| {