From 238d2e3c44366aba9dc5c770c95475765a6725cb Mon Sep 17 00:00:00 2001
From: Sourab Mangrulkar <13534540+pacman100@users.noreply.github.com>
Date: Sat, 16 Dec 2023 19:41:43 +0530
Subject: [PATCH] fix resuming from ckpt when using FSDP with FULL_STATE_DICT
 (#27891)

* fix resuming from ckpt when suing FSDP with FULL_STATE_DICT

* update tests

* fix tests
---
 src/transformers/trainer.py | 13 +++++++++----
 tests/fsdp/test_fsdp.py     | 14 ++++++++++++++
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/src/transformers/trainer.py b/src/transformers/trainer.py
index ffe5f5c0d1556b..9cd0bf0685e6c9 100755
--- a/src/transformers/trainer.py
+++ b/src/transformers/trainer.py
@@ -2033,10 +2033,15 @@ def _load_from_checkpoint(self, resume_from_checkpoint, model=None):
         weights_index_file = os.path.join(resume_from_checkpoint, WEIGHTS_INDEX_NAME)
         safe_weights_file = os.path.join(resume_from_checkpoint, SAFE_WEIGHTS_NAME)
         safe_weights_index_file = os.path.join(resume_from_checkpoint, SAFE_WEIGHTS_INDEX_NAME)
-        is_fsdp_ckpt = os.path.isdir(resume_from_checkpoint) and any(
-            FSDP_MODEL_NAME in folder_name
-            for folder_name in os.listdir(resume_from_checkpoint)
-            if os.path.isdir(os.path.join(resume_from_checkpoint, folder_name))
+        is_fsdp_ckpt = os.path.isdir(resume_from_checkpoint) and (
+            # this checks the FSDP state dict when `SHARDED_STATE_DICT` is used
+            any(
+                FSDP_MODEL_NAME in folder_name
+                for folder_name in os.listdir(resume_from_checkpoint)
+                if os.path.isdir(os.path.join(resume_from_checkpoint, folder_name))
+            )
+            # this checks the FSDP state dict when `FULL_STATE_DICT` is used
+            or os.path.isfile(os.path.join(resume_from_checkpoint, f"{FSDP_MODEL_NAME}.bin"))
         )
 
         if is_fsdp_ckpt and not self.is_fsdp_enabled:
diff --git a/tests/fsdp/test_fsdp.py b/tests/fsdp/test_fsdp.py
index 2a9473c862ffa9..d883f29ed3698c 100644
--- a/tests/fsdp/test_fsdp.py
+++ b/tests/fsdp/test_fsdp.py
@@ -41,6 +41,7 @@
 
 if is_torch_available():
     from transformers.pytorch_utils import is_torch_greater_or_equal_than_2_1
+    from transformers.trainer import FSDP_MODEL_NAME
 else:
     is_torch_greater_or_equal_than_2_1 = False
 
@@ -211,6 +212,19 @@ def test_training_and_can_resume_normally(self, state_dict_type):
         # resume from ckpt
         checkpoint = os.path.join(output_dir, "checkpoint-115")
         resume_args = args + f"--resume_from_checkpoint {checkpoint}".split()
+
+        is_fsdp_ckpt = os.path.isdir(checkpoint) and (
+            # this checks the FSDP state dict when `SHARDED_STATE_DICT` is used
+            any(
+                FSDP_MODEL_NAME in folder_name
+                for folder_name in os.listdir(checkpoint)
+                if os.path.isdir(os.path.join(checkpoint, folder_name))
+            )
+            # this checks the FSDP state dict when `FULL_STATE_DICT` is used
+            or os.path.isfile(os.path.join(checkpoint, f"{FSDP_MODEL_NAME}.bin"))
+        )
+        self.assertTrue(is_fsdp_ckpt)
+
         logs_resume = self.run_cmd_and_get_logs(
             use_accelerate, sharding_strategy, launcher, script, resume_args, output_dir
         )