When deleting EXIF IFD tag, delete IFD data (#9083)

Author: hugovk

Tests/test_image.py

@@ -953,6 +953,17 @@ def test_exif_ifd(self) -> None:
         reloaded_exif.load(exif.tobytes())
         assert reloaded_exif.get_ifd(0x8769) == exif.get_ifd(0x8769)
 
+    def test_delete_ifd_tag(self) -> None:
+        with Image.open("Tests/images/flower.jpg") as im:
+            exif = im.getexif()
+        exif.get_ifd(0x8769)
+        assert 0x8769 in exif
+        del exif[0x8769]
+
+        reloaded_exif = Image.Exif()
+        reloaded_exif.load(exif.tobytes())
+        assert 0x8769 not in reloaded_exif
+
     def test_exif_load_from_fp(self) -> None:
         with Image.open("Tests/images/flower.jpg") as im:
             data = im.info["exif"]

src/PIL/Image.py

@@ -4218,6 +4218,8 @@ def __delitem__(self, tag: int) -> None:
             del self._info[tag]
         else:
             del self._data[tag]
+            if tag in self._ifds:
+                del self._ifds[tag]
 
     def __iter__(self) -> Iterator[int]:
         keys = set(self._data)