From a71231f39808bfe511f9322341cbfefe9296ec61 Mon Sep 17 00:00:00 2001
From: Serge Barral <serge.barral@asynchronics.com>
Date: Sun, 19 Jan 2025 17:23:38 +0100
Subject: [PATCH] Make the clock's SyncStatus #[must_use]

---
 nexosim/src/simulation.rs          | 12 ++++++++++--
 nexosim/src/simulation/sim_init.rs | 11 ++++++++---
 nexosim/src/time/clock.rs          |  3 ++-
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/nexosim/src/simulation.rs b/nexosim/src/simulation.rs
index 55ea54d..4bc52d2 100644
--- a/nexosim/src/simulation.rs
+++ b/nexosim/src/simulation.rs
@@ -519,13 +519,21 @@ impl Simulation {
         loop {
             match self.step_to_next(target_time) {
                 // The target time was reached exactly.
-                Ok(reached_time) if reached_time == target_time => return Ok(()),
+                Ok(time) if time == target_time => return Ok(()),
                 // No actions are scheduled before or at the target time.
                 Ok(None) => {
                     if let Some(target_time) = target_time {
                         // Update the simulation time.
                         self.time.write(target_time);
-                        self.clock.synchronize(target_time);
+                        if let SyncStatus::OutOfSync(lag) = self.clock.synchronize(target_time) {
+                            if let Some(tolerance) = &self.clock_tolerance {
+                                if &lag > tolerance {
+                                    self.is_terminated = true;
+
+                                    return Err(ExecutionError::OutOfSync(lag));
+                                }
+                            }
+                        }
                     }
                     return Ok(());
                 }
diff --git a/nexosim/src/simulation/sim_init.rs b/nexosim/src/simulation/sim_init.rs
index 9969dd4..7200320 100644
--- a/nexosim/src/simulation/sim_init.rs
+++ b/nexosim/src/simulation/sim_init.rs
@@ -6,8 +6,7 @@ use std::time::Duration;
 use crate::channel::ChannelObserver;
 use crate::executor::{Executor, SimulationContext};
 use crate::model::ProtoModel;
-use crate::time::{AtomicTime, MonotonicTime, TearableAtomicTime};
-use crate::time::{Clock, NoClock};
+use crate::time::{AtomicTime, Clock, MonotonicTime, NoClock, SyncStatus, TearableAtomicTime};
 use crate::util::priority_queue::PriorityQueue;
 use crate::util::sync_cell::SyncCell;
 
@@ -162,7 +161,13 @@ impl SimInit {
         start_time: MonotonicTime,
     ) -> Result<(Simulation, Scheduler), ExecutionError> {
         self.time.write(start_time);
-        self.clock.synchronize(start_time);
+        if let SyncStatus::OutOfSync(lag) = self.clock.synchronize(start_time) {
+            if let Some(tolerance) = &self.clock_tolerance {
+                if &lag > tolerance {
+                    return Err(ExecutionError::OutOfSync(lag));
+                }
+            }
+        }
 
         let scheduler = Scheduler::new(
             self.scheduler_queue.clone(),
diff --git a/nexosim/src/time/clock.rs b/nexosim/src/time/clock.rs
index 789558d..a93ac93 100644
--- a/nexosim/src/time/clock.rs
+++ b/nexosim/src/time/clock.rs
@@ -30,6 +30,7 @@ impl<C: Clock + ?Sized> Clock for Box<C> {
 
 /// The current synchronization status of a clock.
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[must_use]
 pub enum SyncStatus {
     /// The clock is synchronized.
     Synchronized,
@@ -207,7 +208,7 @@ mod test {
         let now = Instant::now();
         let mut clock = SystemClock::from_instant(t0, now);
         let t1 = t0 + Duration::from_millis(200);
-        clock.synchronize(t1);
+        assert_eq!(clock.synchronize(t1), SyncStatus::Synchronized);
         let elapsed = now.elapsed().as_secs_f64();
         let dt = t1.duration_since(t0).as_secs_f64();