修复了 dist 为 None 时的 set_dist_repro_dataloader 的逻辑

fastNLP/core/drivers/torch_driver/ddp.py

@@ -471,12 +471,11 @@ class TorchDDPDriver(TorchDriver):
                 raise RuntimeError("It is not allowed to use checkpoint retraining when you initialize ddp out of our "
                                    "control.")
             else:
-                if isinstance(dist, ReproducibleBatchSampler):
-                    dist = re_instantiate_sampler(dist)
-                    return replace_batch_sampler(dataloader, dist)
-                if isinstance(dist, ReproducibleSampler):
-                    dist = re_instantiate_sampler(dist)
-                    return replace_sampler(dataloader, dist)
+                args = self.get_dataloader_args(dataloader)
+                if isinstance(args.batch_sampler, ReproducibleBatchSampler):
+                    return replace_batch_sampler(dataloader, re_instantiate_sampler(args.batch_sampler))
+                if isinstance(args.sampler, ReproducibleSampler):
+                    return replace_sampler(dataloader, re_instantiate_sampler(args.sampler))
                 return dataloader
         # trainer
         elif dist == "dist":