add CrossProcessLockError::LockPoisoned

Author: Hywan

crates/matrix-sdk-common/src/cross_process_lock.rs

@@ -240,6 +240,11 @@ where
         // function, to avoid multiple reentrant calls.
         let mut _attempt = self.locking_attempt.lock().await;
 
+        // The lock is already poisoned? Let's stop here.
+        if self.is_poisoned() {
+            return Err(CrossProcessLockError::LockPoisoned);
+        }
+
         // If another thread obtained the lock, make sure to only superficially increase
         // the number of holders, and carry on.
         if self.num_holders.load(Ordering::SeqCst) > 0 {
@@ -274,6 +279,8 @@ where
                         "The lock has been acquired, but it's been poisoned!"
                     );
                     self.is_poisoned.store(true, Ordering::SeqCst);
+
+                    return Err(CrossProcessLockError::LockPoisoned);
                 }
 
                 // This was the same generation, no problem.
@@ -340,6 +347,11 @@ where
                     }
                 }
 
+                // The lock has been poisoned. Exit the loop.
+                if this.is_poisoned() {
+                    break;
+                }
+
                 sleep(Duration::from_millis(EXTEND_LEASE_EVERY_MS)).await;
 
                 match this
@@ -459,6 +471,11 @@ pub enum CrossProcessLockError {
     #[error("a lock timed out")]
     LockTimeout,
 
+    /// The lock has been poisoned, it means an holder took it before the lock
+    /// was acquired or renewed.
+    #[error("a lock has been poisoned")]
+    LockPoisoned,
+
     #[error(transparent)]
     #[cfg(not(target_family = "wasm"))]
     TryLockError(#[from] Box<dyn Error + Send + Sync>),