From 60cde73cee8c08bd5c6efb88eb0d511c6c025620 Mon Sep 17 00:00:00 2001
From: Maxence Boutet <mboutet@explorance.com>
Date: Wed, 9 Jun 2021 18:05:04 -0400
Subject: [PATCH 1/2] Ensure that the exception objects are not mutated when
 generated report

---
 locust/html.py          | 5 ++++-
 locust/test/test_web.py | 8 ++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/locust/html.py b/locust/html.py
index 34ecfcd3bf..0ec71c5d22 100644
--- a/locust/html.py
+++ b/locust/html.py
@@ -1,3 +1,5 @@
+from copy import deepcopy
+
 from jinja2 import Environment, FileSystemLoader
 import os
 import pathlib
@@ -36,7 +38,8 @@ def get_html_report(environment, show_download_link=True):
     requests_statistics = list(chain(sort_stats(stats.entries), [stats.total]))
     failures_statistics = sort_stats(stats.errors)
     exceptions_statistics = []
-    for exc in environment.runner.exceptions.values():
+    exceptions = deepcopy(environment.runner.exceptions)
+    for exc in exceptions.values():
         exc["nodes"] = ", ".join(exc["nodes"])
         exceptions_statistics.append(exc)
 
diff --git a/locust/test/test_web.py b/locust/test/test_web.py
index b6c522c8bc..f7d7cf20d2 100644
--- a/locust/test/test_web.py
+++ b/locust/test/test_web.py
@@ -356,6 +356,14 @@ def test_report_exceptions(self):
         # self.assertEqual(200, r.status_code)
         self.assertIn("<h2>Exceptions Statistics</h2>", r.text)
 
+        # Prior to 088a98bf8ff4035a0de3becc8cd4e887d618af53, the "nodes" field for each exception in
+        # "self.runner.exceptions" was accidentally mutated in "get_html_report" to a string.
+        # This assertion reproduces the issue and it is left there to make sure there's no
+        # regression in the future.
+        self.assertTrue(
+            isinstance(next(iter(self.runner.exceptions.values()))["nodes"], set), "exception object has been mutated"
+        )
+
 
 class TestWebUIAuth(LocustTestCase):
     def setUp(self):

From 08716b2e11490de0594ef2ed74f1891d15cfcf0f Mon Sep 17 00:00:00 2001
From: Maxence Boutet <mboutet@explorance.com>
Date: Fri, 11 Jun 2021 15:33:19 -0400
Subject: [PATCH 2/2] Use a list comprehension with dict-unpacking instead of
 deepcopy

---
 locust/html.py | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/locust/html.py b/locust/html.py
index 0ec71c5d22..49f4ebb97e 100644
--- a/locust/html.py
+++ b/locust/html.py
@@ -1,5 +1,3 @@
-from copy import deepcopy
-
 from jinja2 import Environment, FileSystemLoader
 import os
 import pathlib
@@ -37,11 +35,9 @@ def get_html_report(environment, show_download_link=True):
 
     requests_statistics = list(chain(sort_stats(stats.entries), [stats.total]))
     failures_statistics = sort_stats(stats.errors)
-    exceptions_statistics = []
-    exceptions = deepcopy(environment.runner.exceptions)
-    for exc in exceptions.values():
-        exc["nodes"] = ", ".join(exc["nodes"])
-        exceptions_statistics.append(exc)
+    exceptions_statistics = [
+        {**exc, "nodes": ", ".join(exc["nodes"])} for exc in environment.runner.exceptions.values()
+    ]
 
     history = stats.history