Add ability to leverage PRAW8's ReadOnlyException in user.me

(cherry picked from commit bb0e00f7ec628f7dfcd0396f3da323c121f22aa1)

CHANGES.rst

@@ -4,6 +4,13 @@ Change Log
 Unreleased
 ----------
 
+**Deprecated**
+
+* :meth:`.me` will no longer return ``None`` when called in read-only mode starting in
+  Async PRAW 8. A ``DeprecationWarning`` will be issued. To switch forward to the Async
+  PRAW 8 behavior set ``praw8_raise_exception_on_me=True`` in your
+  ``asyncpraw.Reddit(...)`` call.
+
 7.1.1 (2021/02/11)
 ------------------
 

asyncpraw/exceptions.py

@@ -218,6 +218,10 @@ class MissingRequiredAttributeException(ClientException):
     """Indicate exceptions caused by not including a required attribute."""
 
 
+class ReadOnlyException(ClientException):
+    """Raised when a method call requires read_only mode to be disabled."""
+
+
 class TooLargeMediaException(ClientException):
     """Indicate exceptions from uploading media that's too large."""
 

asyncpraw/models/user.py

@@ -3,6 +3,7 @@
 from warnings import warn
 
 from ..const import API_PATH
+from ..exceptions import ReadOnlyException
 from ..models import Preferences
 from ..util.cache import cachedproperty
 from .base import AsyncPRAWBase
@@ -129,18 +130,22 @@ async def me(
         .. deprecated:: 7.2
 
             In read-only mode this method returns ``None``. In Async PRAW 8 this method
-            will raise :class:`.ReadOnlyException` when called in read-only mode.
+            will raise :class:`.ReadOnlyException` when called in read-only mode. To
+            operate in Async PRAW 8 mode, set the config variable
+            ``praw8_raise_exception_on_me`` to True.
 
         """
         if self._reddit.read_only:
-            warn(
-                "The `None` return value is deprecated, and will raise a "
-                "`ReadOnlyException` beginning with Async PRAW 8. See documentation "
-                "for forward compatibility options.",
-                category=DeprecationWarning,
-                stacklevel=2,
-            )
-            return None
+            if not self._reddit.config.custom.get("praw8_raise_exception_on_me"):
+                warn(
+                    "The `None` return value is deprecated, and will raise a "
+                    "`ReadOnlyException` beginning with Async PRAW 8. See "
+                    "documentation for forward compatibility options.",
+                    category=DeprecationWarning,
+                    stacklevel=2,
+                )
+                return None
+            raise ReadOnlyException("`user.me()` does not work in read_only mode")
         if "_me" not in self.__dict__ or not use_cache:
             user_data = await self._reddit.get(API_PATH["me"])
             self._me = Redditor(self._reddit, _data=user_data)

tests/unit/models/test_user.py

@@ -1,10 +1,26 @@
+import pytest
+
+from asyncpraw import Reddit
+from asyncpraw.exceptions import ReadOnlyException
 from asyncpraw.models import User
 
 from .. import UnitTest
 
 
 class TestUser(UnitTest):
     async def test_me__in_read_only_mode(self):
+        self.reddit = Reddit(
+            client_id="dummy",
+            client_secret="dummy",
+            praw8_raise_exception_on_me=True,
+            user_agent="dummy",
+        )
+        self.reddit._core._requestor._http = None
         assert self.reddit.read_only
         user = User(self.reddit)
-        assert await user.me() is None
+        with pytest.raises(ReadOnlyException):
+            await user.me()
+
+    async def test_me__in_read_only_mode__deprecated(self):
+        assert self.reddit.read_only
+        assert await User(self.reddit).me() is None