From 61c39074f507640b14cd7ff53a8ec060b1acfd46 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Fri, 25 Jun 2021 19:46:58 +1000
Subject: [PATCH] Fixed undefined variable in logging

---
 Tests/test_file_tiff_metadata.py | 13 +++++++++++++
 src/PIL/TiffImagePlugin.py       |  3 ++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Tests/test_file_tiff_metadata.py b/Tests/test_file_tiff_metadata.py
index e2841163b31..1b55d5dc47e 100644
--- a/Tests/test_file_tiff_metadata.py
+++ b/Tests/test_file_tiff_metadata.py
@@ -376,3 +376,16 @@ def test_too_many_entries():
 
     # Should not raise ValueError.
     pytest.warns(UserWarning, lambda: ifd[277])
+
+
+def test_empty_subifd(tmp_path):
+    out = str(tmp_path / "temp.jpg")
+
+    im = hopper()
+    exif = im.getexif()
+    exif[TiffImagePlugin.EXIFIFD] = {}
+    im.save(out, exif=exif)
+
+    with Image.open(out) as reloaded:
+        exif = reloaded.getexif()
+        assert exif.get_ifd(TiffImagePlugin.EXIFIFD) == {}
diff --git a/src/PIL/TiffImagePlugin.py b/src/PIL/TiffImagePlugin.py
index fc59f14d39e..7f1bf4d9d4d 100644
--- a/src/PIL/TiffImagePlugin.py
+++ b/src/PIL/TiffImagePlugin.py
@@ -826,7 +826,8 @@ def tobytes(self, offset=0):
                 else:
                     ifh = b"MM\x00\x2A\x00\x00\x00\x08"
                 ifd = ImageFileDirectory_v2(ifh)
-                for ifd_tag, ifd_value in self._tags_v2[tag].items():
+                values = self._tags_v2[tag]
+                for ifd_tag, ifd_value in values.items():
                     ifd[ifd_tag] = ifd_value
                 data = ifd.tobytes(offset)
             else: