From 84d2cb322625cbaf24ee0fd507308d03020b7a45 Mon Sep 17 00:00:00 2001
From: you-n-g <you-n-g@users.noreply.github.com>
Date: Wed, 25 Aug 2021 18:05:10 +0800
Subject: [PATCH] Update gen.py (#576)

---
 qlib/workflow/task/gen.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/qlib/workflow/task/gen.py b/qlib/workflow/task/gen.py
index e60fa4755..2fc87b1a4 100644
--- a/qlib/workflow/task/gen.py
+++ b/qlib/workflow/task/gen.py
@@ -162,8 +162,7 @@ class RollingGen(TaskGen):
         List[dict]:
             the following tasks of `task`(`task` itself is excluded)
         """
-        t = copy.deepcopy(task)
-        prev_seg = t["dataset"]["kwargs"]["segments"]
+        prev_seg = task["dataset"]["kwargs"]["segments"]
         while True:
             segments = {}
             try:
@@ -184,6 +183,7 @@ class RollingGen(TaskGen):
                 break
 
             prev_seg = segments
+            t = copy.deepcopy(task)  # deepcopy is necessary to avoid modify task inplace
             self._update_task_segs(t, segments)
             yield t