From 0c1c699832c62950d7ac1e83f3b8fc24969de833 Mon Sep 17 00:00:00 2001
From: rhilfers <rhilfers@expedia.com>
Date: Tue, 28 Jan 2020 20:13:29 -0800
Subject: [PATCH] Fixed common tags leaking state between spans (#9)

* fix bug where state is leaked between spans when using common tags feature

* fix linting issue
---
 haystack/tracer.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/haystack/tracer.py b/haystack/tracer.py
index 901afa6..56b1ab5 100644
--- a/haystack/tracer.py
+++ b/haystack/tracer.py
@@ -105,7 +105,8 @@ def start_span(self,
 
         # Set common tags
         if self._common_tags:
-            tags = {**self._common_tags, **tags} if tags else self._common_tags
+            tags = {**self._common_tags, **tags} if tags else \
+                self._common_tags.copy()
 
         return Span(self,
                     operation_name=operation_name,