From c27519960f4d9bbcb089cc6c2903ce518a500276 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Thu, 3 Mar 2022 22:10:19 +1100
Subject: [PATCH] Check if self.im is not None

---
 Tests/test_image_access.py | 15 +++++++++------
 src/PIL/GifImagePlugin.py  |  2 +-
 src/PIL/IcnsImagePlugin.py |  2 +-
 src/PIL/IcoImagePlugin.py  |  2 +-
 src/PIL/Image.py           |  4 ++--
 5 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/Tests/test_image_access.py b/Tests/test_image_access.py
index 7b3036979..bdbfdd0e2 100644
--- a/Tests/test_image_access.py
+++ b/Tests/test_image_access.py
@@ -154,14 +154,17 @@ class TestImageGetPixel(AccessTest):
 
         # Check 0
         im = Image.new(mode, (0, 0), None)
-        with pytest.raises(IndexError):
+        assert im.load() is not None
+
+        error = ValueError if self._need_cffi_access else IndexError
+        with pytest.raises(error):
             im.putpixel((0, 0), c)
-        with pytest.raises(IndexError):
+        with pytest.raises(error):
             im.getpixel((0, 0))
         # Check 0 negative index
-        with pytest.raises(IndexError):
+        with pytest.raises(error):
             im.putpixel((-1, -1), c)
-        with pytest.raises(IndexError):
+        with pytest.raises(error):
             im.getpixel((-1, -1))
 
         # check initial color
@@ -176,10 +179,10 @@ class TestImageGetPixel(AccessTest):
 
         # Check 0
         im = Image.new(mode, (0, 0), c)
-        with pytest.raises(IndexError):
+        with pytest.raises(error):
             im.getpixel((0, 0))
         # Check 0 negative index
-        with pytest.raises(IndexError):
+        with pytest.raises(error):
             im.getpixel((-1, -1))
 
     def test_basic(self):
diff --git a/src/PIL/GifImagePlugin.py b/src/PIL/GifImagePlugin.py
index 4f8ea209d..f3608cdef 100644
--- a/src/PIL/GifImagePlugin.py
+++ b/src/PIL/GifImagePlugin.py
@@ -298,7 +298,7 @@ class GifImageFile(ImageFile.ImageFile):
                 self.dispose = Image.core.fill(dispose_mode, dispose_size, color)
             else:
                 # replace with previous contents
-                if self.im:
+                if self.im is not None:
                     # only dispose the extent in this frame
                     self.dispose = self._crop(self.im, self.dispose_extent)
                 elif frame_transparency is not None:
diff --git a/src/PIL/IcnsImagePlugin.py b/src/PIL/IcnsImagePlugin.py
index 069aff96b..57e3ea12d 100644
--- a/src/PIL/IcnsImagePlugin.py
+++ b/src/PIL/IcnsImagePlugin.py
@@ -287,7 +287,7 @@ class IcnsImageFile(ImageFile.ImageFile):
             )
 
         px = Image.Image.load(self)
-        if self.im and self.im.size == self.size:
+        if self.im is not None and self.im.size == self.size:
             # Already loaded
             return px
         self.load_prepare()
diff --git a/src/PIL/IcoImagePlugin.py b/src/PIL/IcoImagePlugin.py
index b4f84ee20..915e4c928 100644
--- a/src/PIL/IcoImagePlugin.py
+++ b/src/PIL/IcoImagePlugin.py
@@ -304,7 +304,7 @@ class IcoImageFile(ImageFile.ImageFile):
         self._size = value
 
     def load(self):
-        if self.im and self.im.size == self.size:
+        if self.im is not None and self.im.size == self.size:
             # Already loaded
             return Image.Image.load(self)
         im = self.ico.getimage(self.size)
diff --git a/src/PIL/Image.py b/src/PIL/Image.py
index c9265b5ab..5efecf0bf 100644
--- a/src/PIL/Image.py
+++ b/src/PIL/Image.py
@@ -847,7 +847,7 @@ class Image:
         :returns: An image access object.
         :rtype: :ref:`PixelAccess` or :py:class:`PIL.PyAccess`
         """
-        if self.im and self.palette and self.palette.dirty:
+        if self.im is not None and self.palette and self.palette.dirty:
             # realize palette
             mode, arr = self.palette.getdata()
             self.im.putpalette(mode, arr)
@@ -864,7 +864,7 @@ class Image:
                 self.palette.mode = palette_mode
                 self.palette.palette = self.im.getpalette(palette_mode, palette_mode)
 
-        if self.im:
+        if self.im is not None:
             if cffi and USE_CFFI_ACCESS:
                 if self.pyaccess:
                     return self.pyaccess