Add official warnings for the removal of six from vendoring

.changes/next-release/enhancement-Deprecation-17508.json

@@ -0,0 +1,5 @@
+{
+  "type": "enhancement",
+  "category": "Deprecation",
+  "description": "Importing the six module from botocore.compat or botocore.vendored will now raise a deprecation warning. The module will be removed in a future release. Users should add the module as a direct dependency if it's still needed."
+}

botocore/compat.py

@@ -22,11 +22,11 @@
 import shlex
 import re
 import os
+import warnings
 from collections import OrderedDict
 from collections.abc import MutableMapping
 from math import floor
 
-from botocore.vendored import six
 from botocore.exceptions import MD5UnavailableError
 from dateutil.tz import tzlocal
 from urllib3 import exceptions
@@ -360,3 +360,20 @@ def has_minimum_crt_version(minimum_version):
     HAS_GZIP = True
 except ImportError:
     HAS_GZIP = False
+
+
+def __getattr__(name):
+    """
+    Module override to raise warnings when deprecated libraries
+    are imported in external code.
+    """
+    if name == "six":
+        warnstr = (
+            "The botocore.compat.six module is deprecated and will be removed "
+            "in a future version. Please use six as a direct dependency."
+        )
+        warnings.warn(warnstr, DeprecationWarning, stacklevel=2)
+        from botocore.vendored import six
+        return six
+
+    raise AttributeError(f"Module {__name__} has no attribute {name}.")

botocore/vendored/six.py

@@ -27,6 +27,13 @@
 import operator
 import sys
 import types
+import warnings
+
+warnstr = (
+    "The botocore.vendored.six module is deprecated and will be removed "
+    "in a future version. Please use six as a direct dependency."
+)
+warnings.warn(warnstr, DeprecationWarning, stacklevel=2)
 
 __author__ = "Benjamin Peterson <[email protected]>"
 __version__ = "1.16.0"

tests/unit/test_compat.py

@@ -11,6 +11,7 @@
 # ANY KIND, either express or implied. See the License for the specific
 # language governing permissions and limitations under the License.
 import datetime
+import warnings
 
 import pytest
 
@@ -225,3 +226,27 @@ def test_has_crt_global(self):
             assert HAS_CRT
         except ImportError:
             assert not HAS_CRT
+
+
+@pytest.mark.filterwarnings("always::DeprecationWarning")
+def test_six_deprecation_warning():
+    vendored_msg = "The botocore.vendored.six module is deprecated"
+    compat_msg = "The botocore.compat.six module is deprecated"
+
+    # Verify import from vendored raises a warning
+    with pytest.warns(DeprecationWarning, match=vendored_msg):
+        import botocore.vendored.six  # noqa: F401
+
+    # Verify import from compat raises a warning
+    with pytest.warns(DeprecationWarning, match=compat_msg):
+        from botocore.compat import six  # noqa: F401
+
+    # Verify other imports don't raise a warning
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        from botocore.compat import urlparse  # noqa: F401
+
+    # Verify direct import of the module doesn't raise a warning
+    with warnings.catch_warnings():
+        warnings.simplefilter("error")
+        import botocore.compat  # noqa: F401