From 293a3b53d2f12ca20bd5ceca29516491c94b5f33 Mon Sep 17 00:00:00 2001
From: tstadel <60758086+tstadel@users.noreply.github.com>
Date: Wed, 8 Jun 2022 19:43:09 +0200
Subject: [PATCH] Fix params being changed during pipeline.eval() (#2638)

---
 haystack/pipelines/base.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/haystack/pipelines/base.py b/haystack/pipelines/base.py
index 5a2620d56..750f268a3 100644
--- a/haystack/pipelines/base.py
+++ b/haystack/pipelines/base.py
@@ -1109,6 +1109,8 @@ class Pipeline:
         if add_isolated_node_eval:
             if params is None:
                 params = {}
+            else:
+                params = params.copy()
             params["add_isolated_node_eval"] = True
 
         # if documents is None, set docs_per_label to None for each label