chore: added suggestion

Signed-off-by: Manish Dait <daitmanish88@gmail.com>

Author: manishdait

examples/test.py

@@ -0,0 +1,32 @@
+from hiero_sdk_python.account.account_create_transaction import AccountCreateTransaction
+from hiero_sdk_python.account.account_id import AccountId
+from hiero_sdk_python.client.client import Client
+from hiero_sdk_python.consensus.topic_id import TopicId
+from hiero_sdk_python.consensus.topic_message_submit_transaction import TopicMessageSubmitTransaction
+from hiero_sdk_python.crypto.private_key import PrivateKey
+
+
+def main() -> None:
+    client = Client.from_env()
+    tx = (
+        AccountCreateTransaction()
+        .set_key(PrivateKey.generate())
+        .set_node_account_id(AccountId(0, 0, 3))
+        .freeze_with(client)
+    )
+    print(tx.size)
+    print(tx.body_size)
+
+    tx2 = (
+        TopicMessageSubmitTransaction()
+        .set_topic_id(TopicId.from_string("0.0.23"))
+        .set_message("A" * 1300)
+        .freeze_with(client)
+    )
+    print(tx2.size)
+    print(tx2.body_size)
+    print(tx2.body_size_all_chunks)
+
+
+if __name__ == "__main__":
+    main()

src/hiero_sdk_python/consensus/topic_message_submit_transaction.py

@@ -265,8 +265,10 @@ def freeze_with(self, client: Client) -> TopicMessageSubmitTransaction:
 
                     chunk_transaction_id = self.transaction_id
                 else:
+                    next_nanos = base_timestamp.nanos + i
+
                     chunk_valid_start = timestamp_pb2.Timestamp(
-                        seconds=base_timestamp.seconds, nanos=base_timestamp.nanos + i
+                        seconds=base_timestamp.seconds + next_nanos // 1_000_000_000, nanos=next_nanos % 1_000_000_000
                     )
                     chunk_transaction_id = TransactionId(
                         account_id=self.transaction_id.account_id, valid_start=chunk_valid_start
@@ -412,10 +414,15 @@ def body_size_all_chunks(self) -> list[int]:
 
         original_index = self._current_index
         original_transaction_id = self.transaction_id
-        for transaction_id in self._transaction_ids:
-            self.transaction_id = transaction_id
-            sizes.append(self.body_size)
 
-        self._current_index = original_index
-        self.transaction_id = original_transaction_id
+        try:
+            for i, transaction_id in enumerate(self._transaction_ids):
+                self._current_index = i
+                self.transaction_id = transaction_id
+
+                sizes.append(self.body_size)
+        finally:
+            self._current_index = original_index
+            self.transaction_id = original_transaction_id
+
         return sizes

src/hiero_sdk_python/file/file_append_transaction.py

@@ -299,8 +299,10 @@ def freeze_with(self, client: Client) -> FileAppendTransaction:
                 else:
                     # Subsequent chunks get incremented timestamps
                     # Add i nanoseconds to space out chunks
+                    next_nanos = base_timestamp.nanos + i
+
                     chunk_valid_start = timestamp_pb2.Timestamp(
-                        seconds=base_timestamp.seconds, nanos=base_timestamp.nanos + i
+                        seconds=base_timestamp.seconds + next_nanos // 1_000_000_000, nanos=next_nanos % 1_000_000_000
                     )
                     chunk_transaction_id = TransactionId(
                         account_id=self.transaction_id.account_id, valid_start=chunk_valid_start
@@ -456,10 +458,15 @@ def body_size_all_chunks(self) -> list[int]:
 
         original_index = self._current_chunk_index
         original_transaction_id = self.transaction_id
-        for transaction_id in self._transaction_ids:
-            self.transaction_id = transaction_id
-            sizes.append(self.body_size)
 
-        self._current_chunk_index = original_index
-        self.transaction_id = original_transaction_id
+        try:
+            for i, transaction_id in enumerate(self._transaction_ids):
+                self._current_chunk_index = i
+                self.transaction_id = transaction_id
+
+                sizes.append(self.body_size)
+        finally:
+            self._current_chunk_index = original_index
+            self.transaction_id = original_transaction_id
+
         return sizes

tests/unit/transaction_test.py

@@ -423,3 +423,6 @@ def test_chunked_tx_return_proper_sizes(file_id, account_id, transaction_id):
 
     # The larger chunked transaction should be bigger than the single-chunk transaction
     assert large_size > small_size
+
+    # Check for chuck index reset reset
+    assert large_tx._current_chunk_index == 0