From 7b106c397dfa91b32b2c57718e6d37d012768971 Mon Sep 17 00:00:00 2001
From: Tian Gao <gaogaotiantian@hotmail.com>
Date: Fri, 7 Jul 2023 12:36:35 -0700
Subject: [PATCH 1/2] Add fix and regression test for near white color

---
 Lib/colorsys.py           | 8 +++++++-
 Lib/test/test_colorsys.py | 6 ++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/Lib/colorsys.py b/Lib/colorsys.py
index 9bdc83e3772603..44ff97e48554ea 100644
--- a/Lib/colorsys.py
+++ b/Lib/colorsys.py
@@ -78,7 +78,13 @@ def rgb_to_hls(r, g, b):
     sumc = (maxc+minc)
     rangec = (maxc-minc)
     l = sumc/2.0
-    if minc == maxc:
+    # gh-106498
+    # Due to a degree of float precision error, it's possible that maxc != minc
+    # but maxc + minc == 2.0. Which will make (2.0 - sumc) zero, causing the
+    # ZeroDivisionError.
+    # e.g. colorsys.rgb_to_hls(1, 1, 0.9999999999999999)
+    # In this case, it's an extreme near white color so we can just return white
+    if minc == maxc or sumc == 2.0:
         return 0.0, l, 0.0
     if l <= 0.5:
         s = rangec / sumc
diff --git a/Lib/test/test_colorsys.py b/Lib/test/test_colorsys.py
index a24e3adcb4b842..1502394dfc9063 100644
--- a/Lib/test/test_colorsys.py
+++ b/Lib/test/test_colorsys.py
@@ -69,6 +69,12 @@ def test_hls_values(self):
             self.assertTripleEqual(hls, colorsys.rgb_to_hls(*rgb))
             self.assertTripleEqual(rgb, colorsys.hls_to_rgb(*hls))
 
+    def test_hls_corner_case(self):
+        try:
+            colorsys.rgb_to_hls(1, 1, 0.9999999999999999)
+        except Exception:
+            self.fail("rgb_to_hls(1, 1, 0.9999999999999999) raised an exception!")
+
     def test_yiq_roundtrip(self):
         for r in frange(0.0, 1.0, 0.2):
             for g in frange(0.0, 1.0, 0.2):

From c02bdb10d9e41b297e3f0d4965d0e3f3c3a0da66 Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Fri, 7 Jul 2023 19:46:29 +0000
Subject: [PATCH 2/2] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../next/Library/2023-07-07-19-46-27.gh-issue-106498.ijJ-eH.rst  | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2023-07-07-19-46-27.gh-issue-106498.ijJ-eH.rst

diff --git a/Misc/NEWS.d/next/Library/2023-07-07-19-46-27.gh-issue-106498.ijJ-eH.rst b/Misc/NEWS.d/next/Library/2023-07-07-19-46-27.gh-issue-106498.ijJ-eH.rst
new file mode 100644
index 00000000000000..39d1a54c311ed1
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-07-07-19-46-27.gh-issue-106498.ijJ-eH.rst
@@ -0,0 +1 @@
+Fixed :func:`colorsys.rgb_to_hls` under an extreme input.