warsaw · Apr 13, 2022 · Apr 10, 2022 · Apr 10, 2022 · Apr 10, 2022 · Apr 12, 2022
@@ -1,9 +1,6 @@
 # Import smtplib for the actual sending function
 import smtplib
 
-# And imghdr to find the types of our images
-import imghdr
-
 # Here are the email package modules we'll need
 from email.message import EmailMessage
 
@@ -22,7 +19,7 @@
     with open(file, 'rb') as fp:
         img_data = fp.read()
     msg.add_attachment(img_data, maintype='image',
-                                 subtype=imghdr.what(None, img_data))
+                                 subtype="jpeg")
 
 # Send the email via our own SMTP server.
 with smtplib.SMTP('localhost') as s:

@@ -180,11 +180,11 @@ Here are the classes:
    A subclass of :class:`~email.mime.nonmultipart.MIMENonMultipart`, the
    :class:`MIMEImage` class is used to create MIME message objects of major type
    :mimetype:`image`. *_imagedata* is a string containing the raw image data.  If
-   this data can be decoded by the standard Python module :mod:`imghdr`, then the
-   subtype will be automatically included in the :mailheader:`Content-Type` header.
-   Otherwise you can explicitly specify the image subtype via the *_subtype*
-   argument.  If the minor type could not be guessed and *_subtype* was not given,
-   then :exc:`TypeError` is raised.
+   this data can be decoded by the standard Python module :mod:`imghdr`
+   (which is deprecated), then the subtype will be automatically included in the
+   :mailheader:`Content-Type` header. Otherwise you can explicitly specify the
+   image subtype via the *_subtype* argument.  If the minor type could not be
+   guessed and *_subtype* was not given, then :exc:`TypeError` is raised.
 
    Optional *_encoder* is a callable (i.e. function) which will perform the actual
    encoding of the image data for transport.  This callable takes one argument,
@@ -204,6 +204,10 @@ Here are the classes:
    .. versionchanged:: 3.6
       Added *policy* keyword-only parameter.
 
+   .. deprecated:: 3.11
+      The default argument for *_subtype* due :mod:`imghdr` being
+      deprecated.
+
 .. currentmodule:: email.mime.message
 
 .. class:: MIMEMessage(_msg, _subtype='rfc822', *, policy=compat32)

@@ -852,9 +852,14 @@ Deprecated
   * :mod:`cgitb`
   * :mod:`chunk`
   * :mod:`crypt`
+  * :mod:`imghdr`
 
   (Contributed by Brett Cannon in :issue:`47061`.)
 
+* The default argument for *_subtype* for :class:`email.mime.MIMEImage`
+  has been deprecated due to the deprecation of :mod:`imghdr`. Please
+  explicitly provide a an image subtype.
+
 
 Removed
 =======

@@ -6,13 +6,16 @@
 
 __all__ = ['MIMEImage']
 
-import imghdr
-
 from email import encoders
 from email.mime.nonmultipart import MIMENonMultipart
+import warnings
+
+with warnings.catch_warnings():
+    warnings.simplefilter("ignore", DeprecationWarning)
+    import imghdr
+
 
 
-
 class MIMEImage(MIMENonMultipart):
     """Class for generating image/* type MIME documents."""
 
@@ -21,10 +24,10 @@ def __init__(self, _imagedata, _subtype=None,
         """Create an image/* type MIME document.
 
         _imagedata is a string containing the raw image data.  If this data
-        can be decoded by the standard Python `imghdr' module, then the
-        subtype will be automatically included in the Content-Type header.
-        Otherwise, you can specify the specific image subtype via the _subtype
-        parameter.
+        can be decoded by the standard Python `imghdr' module
+        (which is deprecated), then the subtype will be automatically included
+        in the Content-Type header. Otherwise, you can specify the specific
+        image subtype via the _subtype parameter.
 
         _encoder is a function which will perform the actual encoding for
         transport of the image data.  It takes one argument, which is this
@@ -38,6 +41,12 @@ def __init__(self, _imagedata, _subtype=None,
         header.
         """
         if _subtype is None:
+            fullname = f"{__name__}.{self.__class__.__qualname__}"
+            msg = ("The *_subtype* argument's default value for {name}"
+                   "is deprecated due to the deprecation of imghdr (slated for "
+                   "removal in Python {remove}); explicitly specify the image "
+                   "subtype")
+            warnings._deprecated(fullname, msg, remove=(3, 13))
             _subtype = imghdr.what(None, _imagedata)
         if _subtype is None:
             raise TypeError('Could not guess image MIME subtype')

diff --git a/Lib/imghdr.py b/Lib/imghdr.py
@@ -1,9 +1,14 @@
 """Recognize image file formats based on their first few bytes."""
 
 from os import PathLike
+import warnings
 
 __all__ = ["what"]
 
+
+warnings._deprecated(__name__, remove=(3, 13))
+
+
 #-------------------------#
 # Recognize image headers #
 #-------------------------#

@@ -7,6 +7,7 @@
 import base64
 import unittest
 import textwrap
+import warnings
 
 from io import StringIO, BytesIO
 from itertools import chain
@@ -799,7 +800,7 @@ class TestEncoders(unittest.TestCase):
     def test_EncodersEncode_base64(self):
         with openfile('PyBanner048.gif', 'rb') as fp:
             bindata = fp.read()
-        mimed = email.mime.image.MIMEImage(bindata)
+        mimed = email.mime.image.MIMEImage(bindata, 'gif')
         base64ed = mimed.get_payload()
         # the transfer-encoded body lines should all be <=76 characters
         lines = base64ed.split('\n')
@@ -1557,7 +1558,7 @@ class TestMIMEImage(unittest.TestCase):
     def setUp(self):
         with openfile('PyBanner048.gif', 'rb') as fp:
             self._imgdata = fp.read()
-        self._im = MIMEImage(self._imgdata)
+        self._im = MIMEImage(self._imgdata, _subtype='gif')
 
     def test_guess_minor_type(self):
         self.assertEqual(self._im.get_content_type(), 'image/gif')
@@ -1590,6 +1591,12 @@ def test_add_header(self):
         self.assertIs(self._im.get_param('attachment', missing,
                                          header='foobar'), missing)
 
+    def test_subtype_default_deprecation(self):
+        with warnings.catch_warnings():
+            warnings.simplefilter("error", DeprecationWarning)
+            with self.assertRaises(DeprecationWarning):
+                self._im = MIMEImage(self._imgdata)
+
 
 
 # Test the basic MIMEApplication class
@@ -1750,7 +1757,7 @@ def setUp(self):
         with openfile('PyBanner048.gif', 'rb') as fp:
             data = fp.read()
         container = MIMEBase('multipart', 'mixed', boundary='BOUNDARY')
-        image = MIMEImage(data, name='dingusfish.gif')
+        image = MIMEImage(data, name='dingusfish.gif', _subtype="gif")
         image.add_header('content-disposition', 'attachment',
                          filename='dingusfish.gif')
         intro = MIMEText('''\
@@ -3449,7 +3456,7 @@ def test_mime_classes_policy_argument(self):
         classes = [
             (MIMEApplication, ('',)),
             (MIMEAudio, (audiodata,)),
-            (MIMEImage, (bindata,)),
+            (MIMEImage, (bindata, 'gif')),
             (MIMEMessage, (Message(),)),
             (MIMENonMultipart, ('multipart', 'mixed')),
             (MIMEText, ('',)),

diff --git a/Lib/test/test_imghdr.py b/Lib/test/test_imghdr.py
@@ -1,12 +1,13 @@
-import imghdr
 import io
 import os
 import pathlib
 import unittest
 import warnings
-from test.support import findfile
+from test.support import findfile, warnings_helper
 from test.support.os_helper import TESTFN, unlink
 
+imghdr = warnings_helper.import_deprecated("imghdr")
+
 
 TEST_FILES = (
     ('python.png', 'png'),

diff --git a/Misc/NEWS.d/next/Library/2022-04-11-17-04-38.gh-issue-91217.QVDLOq.rst b/Misc/NEWS.d/next/Library/2022-04-11-17-04-38.gh-issue-91217.QVDLOq.rst
@@ -0,0 +1,2 @@
+Deprecate the imghdr module. Along the way, deprecate the default argument
+for email.mime.MIMEImage's *_subtype* parameter.
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		Deprecate the imghdr module. Along the way, deprecate the default argument
		for email.mime.MIMEImage's _subtype parameter.