Fix signer capitulation to account for timing out its local view and sending an update

Signed-off-by: Jacinta Ferrant <236437600+jacinta-stacks@users.noreply.github.com>

Author: jacinta-stacks

stacks-node/src/nakamoto_node/stackerdb_listener.rs

@@ -51,6 +51,11 @@ use crate::Config;
 /// Used to test that the signers will broadcast a block if it gets enough signatures
 pub static TEST_IGNORE_SIGNERS: LazyLock<TestFlag<bool>> = LazyLock::new(TestFlag::default);
 
+#[cfg(test)]
+/// Fault injection flag to prevent the miner from notifying listeners about signer signatures across a block.
+pub static TEST_STALL_BLOCK_NOTIFICATION: LazyLock<TestFlag<bool>> =
+    LazyLock::new(TestFlag::default);
+
 /// How long should the coordinator poll on the event receiver before
 /// waking up to check timeouts?
 pub static EVENT_RECEIVER_POLL: Duration = Duration::from_millis(500);
@@ -425,6 +430,7 @@ impl StackerDBListener {
 
                         if block.total_weight_approved >= self.weight_threshold {
                             // Signal to anyone waiting on this block that we have enough signatures
+                            Self::fault_injection_stall_notification();
                             cvar.notify_all();
                         }
 
@@ -605,6 +611,24 @@ impl StackerDBListener {
     fn fault_injection_ignore_signatures() -> bool {
         false
     }
+
+    #[cfg(test)]
+    fn fault_injection_stall_notification() {
+        let mut first_stall = true;
+        while TEST_STALL_BLOCK_NOTIFICATION.get() {
+            std::thread::sleep(Duration::from_millis(100));
+            if first_stall {
+                warn!("StackerDBListener: fault injection: stalling block notification to miner");
+                first_stall = false;
+            }
+        }
+        info!("StackerDBListener: fault injection: resuming block notification to miner");
+    }
+
+    #[cfg(not(test))]
+    fn fault_injection_stall_notification() {
+        // no-op
+    }
 }
 
 impl Drop for StackerDBListener {