style: ruff up things

* Reduce ruff ignore list: fix 12 rule categories

Fixes and removes from pyproject.toml ignore list:
- UP008: super() style (9 violations, auto-fixed)
- UP045/UP007: Optional[X] type hints (16 violations, auto-fixed + dead code removed)
- UP036: outdated sys.version_info check in tests (1 violation)
- B011: assert False → raise AssertionError (4 violations)
- B018: useless property accesses replaced with explicit method calls (6 violations)
- B026: star-arg after keyword in Principal() call (1 violation)
- B028: missing stacklevel= in warnings.warn() (1 violation)
- B904: raise-from in except clauses (2 violations)
- E721: == for type comparisons → is (5 violations)
- E731: lambda assignments → def (4 violations)
- B007, UP007, F403: were already clean

Also removed dead code: TimeStamp type alias was silently undefined in
calendarobjectresource.py, collection.py and davobject.py (try/except
block was failing because `date` was never imported).

Remaining ignore list annotated with violation counts and links to
#634

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: tobixen

caldav/__init__.py

@@ -20,7 +20,8 @@
 
     warnings.warn(
         "You need to install the `build` package and do a `python -m build` "
-        "to get caldav.__version__ set correctly"
+        "to get caldav.__version__ set correctly",
+        stacklevel=2,
     )
 
 # Silence notification of no default logging handler

caldav/async_davclient.py

@@ -155,9 +155,9 @@ def __init__(
         features: FeatureSet | dict | str | None = None,
         enable_rfc6764: bool = True,
         require_tls: bool = True,
-        rate_limit_handle: Optional[bool] = None,
-        rate_limit_default_sleep: Optional[int] = None,
-        rate_limit_max_sleep: Optional[int] = None,
+        rate_limit_handle: bool | None = None,
+        rate_limit_default_sleep: int | None = None,
+        rate_limit_max_sleep: int | None = None,
     ) -> None:
         """
         Initialize an async DAV client.

caldav/calendarobjectresource.py

@@ -17,20 +17,13 @@
 import warnings
 from collections import defaultdict
 from datetime import datetime, timedelta, timezone
-from typing import TYPE_CHECKING, Any, Optional
+from typing import TYPE_CHECKING, Any, ClassVar, Optional
 from urllib.parse import ParseResult, SplitResult
 
 import icalendar
 from dateutil.rrule import rrulestr
 from icalendar import vCalAddress, vText
 
-try:
-    from typing import ClassVar, Optional
-
-    TimeStamp = Optional[date | datetime]
-except:
-    pass
-
 if TYPE_CHECKING:
     from icalendar import vCalAddress
 
@@ -142,9 +135,7 @@ def __init__(
         CalendarObjectResource has an additional parameter for its constructor:
          * data = "...", vCal data for the event
         """
-        super(CalendarObjectResource, self).__init__(
-            client=client, url=url, parent=parent, id=id, props=props
-        )
+        super().__init__(client=client, url=url, parent=parent, id=id, props=props)
         if data is not None:
             self.data = data
             if id and self._get_component_type_cheap():
@@ -871,9 +862,9 @@ def _put(self, retry_on_failure=True):
                 except ImportError:
                     retry_on_failure = False
             if retry_on_failure:
-                ## This looks like a noop, but the object may be "cleaned".
+                ## Accessing vobject_instance may "clean" the object.
                 ## See https://github.com/python-caldav/caldav/issues/43
-                self.vobject_instance
+                self.get_vobject_instance()
                 return self._put(False)
             else:
                 raise error.PutError(errmsg(r))
@@ -895,7 +886,7 @@ async def _async_put(self, retry_on_failure=True):
                 except ImportError:
                     retry_on_failure = False
             if retry_on_failure:
-                self.vobject_instance
+                self.get_vobject_instance()
                 return await self._async_put(False)
             else:
                 raise error.PutError(errmsg(r))
@@ -950,7 +941,10 @@ def change_attendee_status(self, attendee: Any | None = None, **kwargs) -> None:
         attendee_lines = ical_obj["attendee"]
         if isinstance(attendee_lines, str):
             attendee_lines = [attendee_lines]
-        strip_mailto = lambda x: str(x).lower().replace("mailto:", "")
+
+        def strip_mailto(x):
+            return str(x).lower().replace("mailto:", "")
+
         for attendee_line in attendee_lines:
             if strip_mailto(attendee_line) == strip_mailto(attendee):
                 attendee_line.params.update(kwargs)
@@ -1855,7 +1849,7 @@ def is_pending(self, i=None) -> bool | None:
         if i.get("STATUS", "NEEDS-ACTION") in ("CANCELLED", "COMPLETED"):
             return False
         ## input data does not conform to the RFC
-        assert False
+        raise AssertionError
 
     def uncomplete(self) -> None:
         """Undo completion - marks a completed task as not completed"""

caldav/collection.py

@@ -20,13 +20,6 @@
 
 import icalendar
 
-try:
-    from typing import Optional
-
-    TimeStamp = Optional[date | datetime]
-except:
-    pass
-
 if TYPE_CHECKING:
     from icalendar import vCalAddress
 
@@ -252,7 +245,7 @@ def __init__(
         """
         self._calendar_home_set = calendar_home_set
 
-        super(Principal, self).__init__(client=client, url=url, **kwargs)
+        super().__init__(client=client, url=url, **kwargs)
         if url is None:
             if self.client is None:
                 raise ValueError("Unexpected value None for self.client")
@@ -1819,7 +1812,7 @@ def __init__(
         """
         Will locate the mbox if no url is given
         """
-        super(ScheduleMailbox, self).__init__(client=client, url=url)
+        super().__init__(client=client, url=url)
         self._items = None
         if not client and principal:
             self.client = principal.client
@@ -1853,7 +1846,7 @@ def __init__(
                 # properly fix in a future revision
                 raise error.NotFoundError(
                     "principal has no %s.  %s" % (str(self.findprop()), error.ERR_FRAGMENT)  # type: ignore
-                )
+                ) from None
 
     def get_items(self):
         """

caldav/compatibility_hints.py

@@ -351,7 +351,7 @@ def set_feature(self, feature, value=True):
         elif value is None:
             fc = {feature: {"support": "unknown"}}
         else:
-            assert False
+            raise AssertionError
         self.copyFeatureSet(fc, collapse=False)
         feat_def = self.find_feature(feature)
         feat_type = feat_def.get('type', 'server-feature')
@@ -389,7 +389,7 @@ def copyFeatureSet(self, feature_set, collapse=True):
                     self._validate_support_level(value['support'], feature)
                 server_node.update(value)
             else:
-                assert False
+                raise AssertionError
         if collapse:
             self.collapse()
 
@@ -598,12 +598,12 @@ def _convert_node(self, node, feature_info, return_type, accept_fragile=False):
         hierarchical dict, hence the naming of the method.  I
         considered it too complicated though)
         """
-        if return_type == str:
+        if return_type is str:
             ## TODO: consider feature_info['type'], be smarter about it
             return node.get('support', node.get('enable', node.get('behaviour')))
-        elif return_type == dict:
+        elif return_type is dict:
             return node
-        elif return_type == bool:
+        elif return_type is bool:
             ## TODO: consider feature_info['type'], be smarter about this
             support = node.get('support', 'full')
             if support == 'quirk':
@@ -616,7 +616,7 @@ def _convert_node(self, node, feature_info, return_type, accept_fragile=False):
                 ## TODO: this may be improved
                 return not node.get('enable') and not node.get('behaviour') and not node.get('observed')
         else:
-            assert False
+            raise AssertionError
 
     @classmethod
     def find_feature(cls, feature: str) -> dict:

caldav/config.py

@@ -108,7 +108,9 @@ def read_config(fn, interactive_error=False):
                     # Re-raise YAML errors so they can be handled by caller
                     raise ValueError(f"config file {fn} is neither valid JSON nor YAML: {e}") from e
             except ImportError:
-                raise ValueError(f"config file {fn} is not valid JSON, and pyyaml is not installed")
+                raise ValueError(
+                    f"config file {fn} is not valid JSON, and pyyaml is not installed"
+                ) from None
 
     except FileNotFoundError:
         ## File not found

caldav/davclient.py

@@ -211,9 +211,9 @@ def __init__(
         features: FeatureSet | dict | str = None,
         enable_rfc6764: bool = True,
         require_tls: bool = True,
-        rate_limit_handle: Optional[bool] = None,
-        rate_limit_default_sleep: Optional[int] = None,
-        rate_limit_max_sleep: Optional[int] = None,
+        rate_limit_handle: bool | None = None,
+        rate_limit_default_sleep: int | None = None,
+        rate_limit_max_sleep: int | None = None,
     ) -> None:
         """
         Sets up a HTTPConnection object towards the server in the url.
@@ -453,7 +453,7 @@ def principal(self, *largs, **kwargs):
         calendars.
         """
         if not self._principal:
-            self._principal = Principal(client=self, *largs, **kwargs)
+            self._principal = Principal(*largs, client=self, **kwargs)
         return self._principal
 
     def calendar(self, **kwargs):

caldav/davobject.py

@@ -6,13 +6,6 @@
 
 from lxml import etree
 
-try:
-    from typing import Optional
-
-    TimeStamp = Optional[date | datetime]
-except:
-    pass
-
 if TYPE_CHECKING:
     from .davclient import DAVClient
 

caldav/elements/base.py

@@ -82,14 +82,14 @@ def append(self, element: Self | Iterable[Self]) -> Self:
 
 class NamedBaseElement(BaseElement):
     def __init__(self, name: str | None = None) -> None:
-        super(NamedBaseElement, self).__init__(name=name)
+        super().__init__(name=name)
 
     def xmlelement(self):
         if self.attributes.get("name") is None:
             raise Exception("name attribute must be defined")
-        return super(NamedBaseElement, self).xmlelement()
+        return super().xmlelement()
 
 
 class ValuedBaseElement(BaseElement):
     def __init__(self, value: str | bytes | None = None) -> None:
-        super(ValuedBaseElement, self).__init__(value=value)
+        super().__init__(value=value)

caldav/elements/cdav.py

@@ -88,7 +88,7 @@ class TextMatch(ValuedBaseElement):
     tag: ClassVar[str] = ns("C", "text-match")
 
     def __init__(self, value, collation: str = "i;octet", negate: bool = False) -> None:
-        super(TextMatch, self).__init__(value=value)
+        super().__init__(value=value)
 
         if self.attributes is None:
             raise ValueError("Unexpected value None for self.attributes")
@@ -104,7 +104,7 @@ class TimeRange(BaseElement):
     def __init__(self, start: datetime | None = None, end: datetime | None = None) -> None:
         ## start and end should be an icalendar "date with UTC time",
         ## ref https://datatracker.ietf.org/doc/html/rfc4791#section-9.9
-        super(TimeRange, self).__init__()
+        super().__init__()
 
         if self.attributes is None:
             raise ValueError("Unexpected value None for self.attributes")
@@ -128,7 +128,7 @@ class Expand(BaseElement):
     tag: ClassVar[str] = ns("C", "expand")
 
     def __init__(self, start: datetime | None, end: datetime | None = None) -> None:
-        super(Expand, self).__init__()
+        super().__init__()
 
         if self.attributes is None:
             raise ValueError("Unexpected value None for self.attributes")