From 975ebec2f81c4e5c992d65e6984c8ab122feffa6 Mon Sep 17 00:00:00 2001
From: Ned Batchelder <ned@nedbatchelder.com>
Date: Sat, 11 Aug 2018 16:45:19 -0400
Subject: Hasher needed more information about nesting to avoid collisions

---
 coverage/misc.py   | 1 +
 tests/test_misc.py | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/coverage/misc.py b/coverage/misc.py
index fff2a187..50c8d8ac 100644
--- a/coverage/misc.py
+++ b/coverage/misc.py
@@ -226,6 +226,7 @@ class Hasher(object):
                     continue
                 self.update(k)
                 self.update(a)
+        self.md5.update(b'.')
 
     def hexdigest(self):
         """Retrieve the hex digest of the hash."""
diff --git a/tests/test_misc.py b/tests/test_misc.py
index f3d485cc..1d01537b 100644
--- a/tests/test_misc.py
+++ b/tests/test_misc.py
@@ -47,6 +47,13 @@ class HasherTest(CoverageTest):
         h2.update({'b': 23, 'a': 17})
         self.assertEqual(h1.hexdigest(), h2.hexdigest())
 
+    def test_dict_collision(self):
+        h1 = Hasher()
+        h1.update({'a': 17, 'b': {'c': 1, 'd': 2}})
+        h2 = Hasher()
+        h2.update({'a': 17, 'b': {'c': 1}, 'd': 2})
+        self.assertNotEqual(h1.hexdigest(), h2.hexdigest())
+
 
 class RemoveFileTest(CoverageTest):
     """Tests of misc.file_be_gone."""
-- 
cgit v1.2.1