From 023dcf27c29e2b62c84b171d1473bdebd5fcf0eb Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Sat, 13 Jul 2019 08:37:17 +1000
Subject: [PATCH] Raise the same error if a truncated image is loaded a second
 time

---
 Tests/test_file_jpeg.py   | 4 ++++
 Tests/test_imagefile.py   | 4 ++++
 src/PIL/ImageFile.py      | 1 -
 src/PIL/PngImagePlugin.py | 3 ++-
 4 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py
index 4ade11a2966..a9ba54dd1c1 100644
--- a/Tests/test_file_jpeg.py
+++ b/Tests/test_file_jpeg.py
@@ -372,6 +372,10 @@ def test_truncated_jpeg_throws_IOError(self):
         with self.assertRaises(IOError):
             im.load()
 
+        # Test that the error is raised if loaded a second time
+        with self.assertRaises(IOError):
+            im.load()
+
     def _n_qtables_helper(self, n, test_file):
         im = Image.open(test_file)
         f = self.tempfile("temp.jpg")
diff --git a/Tests/test_imagefile.py b/Tests/test_imagefile.py
index 83170cb2ab5..87bba7c2f1e 100644
--- a/Tests/test_imagefile.py
+++ b/Tests/test_imagefile.py
@@ -113,6 +113,10 @@ def test_truncated_with_errors(self):
         with self.assertRaises(IOError):
             im.load()
 
+        # Test that the error is raised if loaded a second time
+        with self.assertRaises(IOError):
+            im.load()
+
     def test_truncated_without_errors(self):
         if "zip_encoder" not in codecs:
             self.skipTest("PNG (zlib) encoder not available")
diff --git a/src/PIL/ImageFile.py b/src/PIL/ImageFile.py
index e5173a1fb75..49d8ef97ceb 100644
--- a/src/PIL/ImageFile.py
+++ b/src/PIL/ImageFile.py
@@ -243,7 +243,6 @@ def load(self):
                                 if LOAD_TRUNCATED_IMAGES:
                                     break
                                 else:
-                                    self.tile = []
                                     raise IOError(
                                         "image file is truncated "
                                         "(%d bytes not processed)" % len(b)
diff --git a/src/PIL/PngImagePlugin.py b/src/PIL/PngImagePlugin.py
index 10e18e4a071..f69ca046633 100644
--- a/src/PIL/PngImagePlugin.py
+++ b/src/PIL/PngImagePlugin.py
@@ -612,7 +612,7 @@ def _open(self):
             rawmode, data = self.png.im_palette
             self.palette = ImagePalette.raw(rawmode, data)
 
-        self.__idat = length  # used by load_read()
+        self.__prepare_idat = length  # used by load_prepare()
 
     @property
     def text(self):
@@ -645,6 +645,7 @@ def load_prepare(self):
         if self.info.get("interlace"):
             self.decoderconfig = self.decoderconfig + (1,)
 
+        self.__idat = self.__prepare_idat  # used by load_read()
         ImageFile.ImageFile.load_prepare(self)
 
     def load_read(self, read_bytes):