Examine timeout crash

Signed-off-by: Michael X. Grey <[email protected]>

Author: mxgrey

rclrs/src/executor.rs

@@ -487,3 +487,24 @@ impl CreateBasicExecutor for Context {
         self.create_executor(runtime)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::*;
+    use std::time::{Duration, Instant};
+
+    #[test]
+    fn test_spin_once() {
+        let context = Context::default();
+        let mut executor = context.create_basic_executor();
+        let node = executor.create_node("spin_once").unwrap();
+        let subscription = node.create_subscription("test", |msg: crate::vendor::example_interfaces::msg::Empty| { }).unwrap();
+
+        let start = Instant::now();
+
+        for _ in 0..10 {
+            println!("Spinning exeuctor: {:?}", start.elapsed());
+            executor.spin(SpinOptions::default().timeout(Duration::from_secs(1)));
+        }
+    }
+}

rclrs/src/wait_set.rs

@@ -114,11 +114,15 @@ impl WaitSet {
                 })
             }
         };
+
+        dbg!(timeout_ns);
         // SAFETY: The comments in rcl mention "This function cannot operate on the same wait set
         // in multiple threads, and the wait sets may not share content."
-        // We cannot currently guarantee that the wait sets may not share content, but it is
-        // mentioned in the doc comment for `add_subscription`.
-        // Also, the rcl_wait_set is obviously valid.
+        // * We guarantee that the wait sets do not share content by funneling
+        //   the exeuctor of each primitive to one (and only one) WaitSet when
+        //   the primitive gets constructed. The primitive executors are never
+        //   allowed to transfer wait sets.
+        // * The rcl_wait_set is kept valid by the lifecycle of the WaitSet struct.
         match unsafe { rcl_wait(&mut self.handle.rcl_wait_set, timeout_ns) }.ok() {
             Ok(_) => (),
             Err(error) => match error {