fix: free msg_env unconditionally

c_src/main.c

@@ -86,23 +86,16 @@ erlfdb_future_cb(FDBFuture* fdb_future, void* data)
     cancelled = future->cancelled;
     enif_mutex_unlock(future->cancel_lock);
 
-    enif_mutex_lock(future->msg_lock);
-
     if(future->msg_env != NULL) {
-
         if(!cancelled) {
             proc_env = (ErlNifEnv*) erl_drv_tsd_get(future->future_proc_env_key);
             msg = T2(future->msg_env, future->msg_ref, ATOM_ready);
             enif_send(proc_env, &(future->pid), future->msg_env, msg);
-        } else {
-            enif_free_env(future->msg_env);
         }
-
+        enif_free_env(future->msg_env);
         future->msg_env = NULL;
     }
 
-    enif_mutex_unlock(future->msg_lock);
-
     // We're now done with this future which means we need
     // to release our handle to it. See erlfdb_create_future
     // for more on why this happens here.
@@ -132,7 +125,6 @@ erlfdb_create_future(ErlNifEnv* env, FDBFuture* future, ErlFDBFutureGetter gette
     enif_self(env, &(f->pid));
     f->msg_env = enif_alloc_env();
     f->msg_ref = enif_make_copy(f->msg_env, ref);
-    f->msg_lock = enif_mutex_create("fdb:future_msg_lock");
 
     f->cancelled = false;
     f->cancel_lock = enif_mutex_create("fdb:future_cancel_lock");

c_src/resources.c

@@ -90,10 +90,6 @@ erlfdb_future_dtor(ErlNifEnv* env, void* obj)
     if(f->cancel_lock != NULL) {
         enif_mutex_destroy(f->cancel_lock);
     }
-
-    if(f->msg_lock != NULL) {
-        enif_mutex_destroy(f->msg_lock);
-    }
 }
 
 

c_src/resources.h

@@ -36,7 +36,6 @@ struct _ErlFDBFuture
     ErlNifPid pid;
     ErlNifEnv* msg_env;
     ERL_NIF_TERM msg_ref;
-    ErlNifMutex* msg_lock;
     ErlDrvTSDKey future_proc_env_key;
     bool cancelled;
     ErlNifMutex* cancel_lock;