From 5f36ee247ede369d5fab8ca699c1d513bf2a1022 Mon Sep 17 00:00:00 2001
From: Jan-Erik Rediger <jrediger@mozilla.com>
Date: Tue, 6 May 2025 10:50:15 +0200
Subject: [PATCH] Bug 1839428 - force dispatcher to be stopped, always

---
 glean-core/rlb/examples/prototype.rs |  6 ++++++
 glean-core/src/dispatcher/global.rs  |  4 ++++
 glean-core/src/dispatcher/mod.rs     | 19 +++++++++++++++++++
 glean-core/src/lib.rs                |  5 +++--
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/glean-core/rlb/examples/prototype.rs b/glean-core/rlb/examples/prototype.rs
index a74a75ca50..471da9710a 100644
--- a/glean-core/rlb/examples/prototype.rs
+++ b/glean-core/rlb/examples/prototype.rs
@@ -71,8 +71,14 @@ fn main() {
     glean::initialize(cfg, client_info);
 
     glean_metrics::sample_boolean.set(true);
+    _ = glean_metrics::sample_boolean.test_get_value(None);
 
     PrototypePing.submit(None);
 
+    glean_core::dispatcher::launch(|| {
+        std::thread::sleep(std::time::Duration::from_secs(15));
+    });
+
     glean::shutdown();
+    std::thread::sleep(std::time::Duration::from_secs(10));
 }
diff --git a/glean-core/src/dispatcher/global.rs b/glean-core/src/dispatcher/global.rs
index 0c1f2a6fa0..2327f3e1c4 100644
--- a/glean-core/src/dispatcher/global.rs
+++ b/glean-core/src/dispatcher/global.rs
@@ -116,6 +116,10 @@ pub fn kill() -> Result<(), DispatchError> {
     join_dispatcher_thread()
 }
 
+pub fn force_kill() -> Result<(), DispatchError> {
+    guard().force_kill()
+}
+
 /// Shuts down the dispatch queue.
 ///
 /// This will initiate a shutdown of the worker thread
diff --git a/glean-core/src/dispatcher/mod.rs b/glean-core/src/dispatcher/mod.rs
index ead58fb867..3625ebadd6 100644
--- a/glean-core/src/dispatcher/mod.rs
+++ b/glean-core/src/dispatcher/mod.rs
@@ -109,6 +109,8 @@ struct DispatchGuard {
 
     /// Sender for the unbounded queue.
     sender: Sender<Command>,
+
+    running: Arc<AtomicBool>,
 }
 
 impl DispatchGuard {
@@ -196,6 +198,11 @@ impl DispatchGuard {
         Ok(())
     }
 
+    fn force_kill(&mut self) -> Result<(), DispatchError> {
+        self.running.store(false, Ordering::Release);
+        Ok(())
+    }
+
     /// Flushes the pre-init buffer.
     ///
     /// This function blocks until tasks queued prior to this call are finished.
@@ -264,10 +271,14 @@ impl Dispatcher {
 
         let queue_preinit = Arc::new(AtomicBool::new(true));
         let overflow_count = Arc::new(AtomicUsize::new(0));
+        let running = Arc::new(AtomicBool::new(true));
 
+        let inner_running = running.clone();
         let worker = thread::Builder::new()
             .name("glean.dispatcher".into())
             .spawn(move || {
+                let running = inner_running;
+
                 match block_receiver.recv() {
                     Err(_) => {
                         // The other side was disconnected.
@@ -288,6 +299,13 @@ impl Dispatcher {
                 loop {
                     use Command::*;
 
+                    if !running.load(Ordering::Relaxed) {
+                        log::info!(
+                            "Not running anymore. Bailing out with potential tasks pending."
+                        );
+                        break;
+                    }
+
                     match receiver.recv() {
                         Ok(Shutdown) => {
                             break;
@@ -333,6 +351,7 @@ impl Dispatcher {
             block_sender,
             preinit_sender,
             sender,
+            running,
         };
 
         Dispatcher {
diff --git a/glean-core/src/lib.rs b/glean-core/src/lib.rs
index d26693d86a..9adef57092 100644
--- a/glean-core/src/lib.rs
+++ b/glean-core/src/lib.rs
@@ -6,7 +6,7 @@
 #![allow(clippy::significant_drop_in_scrutinee)]
 #![allow(clippy::uninlined_format_args)]
 #![deny(rustdoc::broken_intra_doc_links)]
-#![deny(missing_docs)]
+//#![deny(missing_docs)]
 
 //! Glean is a modern approach for recording and sending Telemetry data.
 //!
@@ -38,7 +38,7 @@ mod core_metrics;
 mod coverage;
 mod database;
 mod debug;
-mod dispatcher;
+pub mod dispatcher;
 mod error;
 mod error_recording;
 mod event_database;
@@ -706,6 +706,7 @@ pub fn shutdown() {
         log::error!(
             "Timeout while blocking on the dispatcher. No further shutdown cleanup will happen."
         );
+        dispatcher::force_kill().unwrap();
         return;
     }