From 64ad0f69d50da1130907e3ac1b30f6cc60a9cd16 Mon Sep 17 00:00:00 2001
From: Iuri de Silvio <iurisilvio@gmail.com>
Date: Sun, 19 Feb 2023 23:25:26 -0300
Subject: [PATCH] Get cache from disk to avoid cache overwriting.

https://github.com/tholo/pytest-flake8/issues/94
---
 pytest_black.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/pytest_black.py b/pytest_black.py
index 04c80cb..d8f706e 100644
--- a/pytest_black.py
+++ b/pytest_black.py
@@ -39,7 +39,9 @@ def pytest_configure(config):
 def pytest_unconfigure(config):
     # save cached mtimes at end of session
     if hasattr(config, "_blackmtimes"):
-        config.cache.set(HISTKEY, config._blackmtimes)
+        cache = config.cache.get(HISTKEY, {})
+        cache.update(config._blackmtimes)
+        config.cache.set(HISTKEY, cache)
 
 
 class BlackItem(pytest.Item, pytest.File):