Drop support for Python 3.6 and old urllib3

.github/workflows/test.yml

@@ -57,8 +57,7 @@ jobs:
         run: |
           set -x
           python -VV
-          # Must pin virtualenv for tox py36 testenv:
+          python -m pip install 'tox<4'
-          python -m pip install 'tox<4' 'virtualenv<20.22.0'
           python -m tox --version
       - name: Test ${{ matrix.tox.name }}
         run: |

CHANGELOG.rst

@@ -25,6 +25,18 @@ Release history
 ^^^^^^^^^^^^^^^
     ..  This extra heading level keeps the ToC from becoming unmanageably long
 
+vNext
+-----
+
+*unreleased changes*
+
+Breaking changes
+~~~~~~~~~~~~~~~~
+
+* Require Python 3.7 or later.
+* Require urllib3 1.25 or later (released 2019-04-29).
+
+
 v9.2
 -----
 

anymail/backends/mailgun.py

@@ -1,33 +1,12 @@
 from datetime import datetime
-from email.utils import encode_rfc2231
 from urllib.parse import quote
 
-from requests import Request
-
 from ..exceptions import AnymailError, AnymailRequestsAPIError
 from ..message import AnymailRecipientStatus
 from ..utils import get_anymail_setting, rfc2822date
 from .base_requests import AnymailRequestsBackend, RequestsPayload
 
 
-# Feature-detect whether requests (urllib3) correctly uses RFC 7578 encoding for non-
-# ASCII filenames in Content-Disposition headers. (This was fixed in urllib3 v1.25.)
-# See MailgunPayload.get_request_params for info (and a workaround on older versions).
-# (Note: when this workaround is removed, please also remove "old_urllib3" tox envs.)
-def is_requests_rfc_5758_compliant():
-    request = Request(
-        method="POST",
-        url="https://www.example.com",
-        files=[("attachment", ("\N{NOT SIGN}.txt", "test", "text/plain"))],
-    )
-    prepared = request.prepare()
-    form_data = prepared.body  # bytes
-    return b"filename*=" not in form_data
-
-
-REQUESTS_IS_RFC_7578_COMPLIANT = is_requests_rfc_5758_compliant()
-
-
 class EmailBackend(AnymailRequestsBackend):
     """
     Mailgun API Email Backend
@@ -163,37 +142,6 @@ class MailgunPayload(RequestsPayload):
             )
         return "%s/messages" % quote(self.sender_domain, safe="")
 
-    def get_request_params(self, api_url):
-        params = super().get_request_params(api_url)
-        non_ascii_filenames = [
-            filename
-            for (field, (filename, content, mimetype)) in params["files"]
-            if filename is not None and not isascii(filename)
-        ]
-        if non_ascii_filenames and not REQUESTS_IS_RFC_7578_COMPLIANT:
-            # Workaround https://github.com/requests/requests/issues/4652:
-            # Mailgun expects RFC 7578 compliant multipart/form-data, and is confused
-            # by Requests/urllib3's improper use of RFC 2231 encoded filename parameters
-            # ("filename*=utf-8''...") in Content-Disposition headers.
-            # The workaround is to pre-generate the (non-compliant) form-data body, and
-            # replace 'filename*={RFC 2231 encoded}' with 'filename="{UTF-8 bytes}"'.
-            # Replace _only_ filenames that will be problems (not all "filename*=...")
-            # to minimize potential side effects--e.g., in attached messages that might
-            # have their own attachments with (correctly) RFC 2231 encoded filenames.
-            prepared = Request(**params).prepare()
-            form_data = prepared.body  # bytes
-            for filename in non_ascii_filenames:  # text
-                rfc2231_filename = encode_rfc2231(filename, charset="utf-8")
-                form_data = form_data.replace(
-                    b"filename*=" + rfc2231_filename.encode("utf-8"),
-                    b'filename="' + filename.encode("utf-8") + b'"',
-                )
-            params["data"] = form_data
-            # Content-Type: multipart/form-data; boundary=...
-            params["headers"]["Content-Type"] = prepared.headers["Content-Type"]
-            params["files"] = None  # these are now in the form_data body
-        return params
-
     def serialize_data(self):
         self.populate_recipient_variables()
         return self.data

pyproject.toml

@@ -1,7 +1,7 @@
 [tool.black]
 force-exclude = '^/tests/test_settings/settings_.*\.py'
 max-line-length = 88
-target-version = ["py36"]
+target-version = ["py37"]
 
 [tool.doc8]
 # ignore very long lines in ESP support table:
@@ -16,4 +16,4 @@ max-line-length = 120
 combine_as_imports = true
 known_first_party = "anymail"
 profile = "black"
-py_version = "36"
+py_version = "37"

setup.py

@@ -45,7 +45,6 @@ requirements_dev = [
     "sphinx-rtd-theme",
     "tox",
     "twine",
-    "virtualenv<20.22.0",  # tox dependency, pinned for Python 3.6 tox testenv
     "wheel",
 ]
 
@@ -71,8 +70,12 @@ setup(
     license="BSD License",
     packages=["anymail"],
     zip_safe=False,
-    python_requires=">=3.6",
+    python_requires=">=3.7",
-    install_requires=["django>=2.0", "requests>=2.4.3"],
+    install_requires=[
+        "django>=2.0",
+        "requests>=2.4.3",
+        "urllib3>=1.25.0",  # requests dependency: fixes RFC 7578 header encoding
+    ],
     extras_require={
         # This can be used if particular backends have unique dependencies.
         # For simplicity, requests is included in the base requirements.
@@ -100,7 +103,6 @@ setup(
         "Programming Language :: Python :: Implementation :: PyPy",
         "Programming Language :: Python :: Implementation :: CPython",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",

tox.ini

@@ -6,7 +6,7 @@ envlist =
     # Test lint, docs, earliest/latest Django first, to catch most errors early...
     lint
     django42-py311-all
-    django30-py36-all
+    django30-py37-all
     docs
     # ... then test all the other supported combinations:
     # Django 4.2: Python 3.8, 3.9, 3.10, 3.11
@@ -15,12 +15,12 @@ envlist =
     django41-py{38,39,310,py38,py39}-all
     # Django 4.0: Python 3.8, 3.9, 3.10
     django40-py{38,39,310,py38,py39}-all
-    # Django 3.2: Python 3.6, 3.7, 3.8, 3.9
+    # Django 3.2: Python 3.6 (eol 2021-12-23), 3.7, 3.8, 3.9
-    django32-py{36,37,38,39,py38,py39}-all
+    django32-py{37,38,39,py38,py39}-all
-    # Django 3.1: Python 3.6, 3.7, 3.8, 3.9 (added in 3.1.3)
+    # Django 3.1: Python 3.6 (eol 2021-12-23), 3.7, 3.8, 3.9 (added in 3.1.3)
-    django31-py{36,37,38,39,py38,py39}-all
+    django31-py{37,38,39,py38,py39}-all
-    # Django 3.0: Python 3.6, 3.7, 3.8, 3.9 (added in 3.0.11)
+    # Django 3.0: Python 3.6 (eol 2021-12-23), 3.7, 3.8, 3.9 (added in 3.0.11)
-    django30-py{37,38,39,py38,py39}-all
+    django30-py{38,39,py38,py39}-all
     # ... then prereleases (if available) and current development:
     # Django 5.0 alpha: Python 3.10+
     #   [not yet in alpha] django50-py{310,311,py310,py311}-all
@@ -28,8 +28,6 @@ envlist =
     djangoDev-py{310,311}-all
     # ... then partial installation (limit extras):
     django42-py311-{none,amazon_ses,postal}
-    # ... then older versions of some dependencies:
-    django32-py37-all-old_urllib3
 
 [testenv]
 deps =
@@ -41,7 +39,6 @@ deps =
     django42: django~=4.2.0
     django50: django~=5.0.0a0
     djangoDev: https://github.com/django/django/tarball/main
-    old_urllib3: urllib3<1.25
 extras =
     # install [test] extras, unconditionally
     test