feat(core): add cleanup_before_exit hook to TauriPlugin trait and docs

Author: Sakina Farukh Ahemad

.changes/use-plugin-cleanups-and-kill-tree.md

@@ -0,0 +1,14 @@
+---
+'@tauri-apps/tauri': 'minor:enhance'
+---
+
+Introduce plugin-level cleanup hooks and centralize process-tree termination logic.
+
+This change:
+- Adds `kill_process_tree` helper to the runtime for cross-platform process-tree shutdown.
+- Adds a new `cleanup_before_exit` lifecycle hook to plugins and wires it so plugin authors
+  can handle sidecar shutdown without core runtime logic.
+- Removes hardcoded sidecar-draining from the runtime and delegates shutdown behavior to plugins.
+
+This allows plugins (such as the shell plugin) to manage their own sidecar processes cleanly
+and improves extensibility of the Tauri runtime. Fixes #14360.

crates/tauri/CHANGELOG.md

@@ -1,16 +1,5 @@
 # Changelog
 
-## \[Unreleased]
-
-### Enhancements
-
-- Added a best-effort process tree killer and plugin-level cleanup hook:
-  - `kill_process_tree(pid: u32)` helper (cross-platform, shell/PowerShell based).
-  - Plugin lifecycle hook `Plugin::cleanup_before_exit` and `PluginStore::cleanup_before_exit` — the runtime now delegates shutdown cleanup to plugins (for example the shell plugin) so they can manage sidecar lifecycle and process termination.
-  - Removed public convenience `AppHandle::register_sidecar` / `unregister_sidecar`: sidecar lifecycle and registration should be owned by the plugin responsible for spawning them.
-  - CLI dev-run integration attempts to kill sidecar descendant processes during terminate.
-  This ensures descendant processes spawned by sidecars are terminated while keeping process-control logic inside the plugin that owns the sidecar (Fixes #14360)
-
 ## \[2.9.2]
 
 ### Bug Fixes

crates/tauri/PR_DRAFT.md

@@ -108,8 +108,8 @@ pub trait Plugin<R: Runtime>: Send {
   ///
   /// Plugins can use this hook to perform any process shutdown/cleanup they need
   /// to do before the runtime exits (for example, killing sidecars or stopping
-  /// background tasks). This is guaranteed to run from the thread performing
-  /// the app cleanup/exit sequence.
+  /// background tasks). This hook is executed inside `App::cleanup_before_exit` during application shutdown.
+
   #[allow(unused_variables)]
   fn cleanup_before_exit(&mut self, app: &AppHandle<R>) {}
 

crates/tauri/src/plugin.rs

@@ -144,6 +144,8 @@ fn restart_macos_app(current_binary: &std::path::Path, env: &Env) {
 /// protected or system processes, or when the caller lacks sufficient
 /// privileges. Callers should handle and log any errors returned by this
 /// function.
+
+// TODO: Move this helper into the `process` plugin in the plugins-workspace repo.
 pub fn kill_process_tree(pid: u32) -> std::io::Result<()> {
   #[cfg(windows)]
   {