ruff: enable PERF checks set

my/core/query.py

@@ -114,7 +114,7 @@ def attribute_func(obj: T, where: Where, default: Optional[U] = None) -> Optiona
             if where(v):
                 return lambda o: o.get(k, default)  # type: ignore[union-attr]
     elif dataclasses.is_dataclass(obj):
-        for (field_name, _annotation) in obj.__annotations__.items():
+        for field_name in obj.__annotations__.keys():
             if where(getattr(obj, field_name)):
                 return lambda o: getattr(o, field_name, default)
     elif is_namedtuple(obj):

my/core/stats.py

@@ -440,7 +440,7 @@ def _guess_datetime(x: Any) -> Optional[datetime]:
         d = asdict(x)
     except:  # noqa: E722 bare except
         return None
-    for _k, v in d.items():
+    for v in d.values():
         if isinstance(v, datetime):
             return v
     return None

my/polar.py

@@ -199,7 +199,7 @@ class Loader:
 
 
     def load_items(self, metas: Json) -> Iterable[Highlight]:
-        for _p, meta in metas.items():
+        for _p, meta in metas.items():  # noqa: PERF102
             with wrap(meta, throw=not config.defensive) as meta:
                 yield from self.load_item(meta)
 

ruff.toml

@@ -10,6 +10,7 @@ lint.extend-select = [
     "PLR", # 'refactor' rules
     "B",   # 'bugbear' set -- various possible bugs
 
+    "PERF", # various potential performance speedups
     # "FA",  # TODO enable later after we make sure cachew works?
     # "ARG", # TODO useful, but results in some false positives in pytest fixtures... maybe later
     # "S",   # bandit (security checks) -- tends to be not very useful, lots of nitpicks
@@ -65,4 +66,12 @@ lint.ignore = [
     "B010",  # same as above, but setattr
     "B017",  # pytest.raises(Exception)
     "B023",  # seems to result in false positives?
+
+    # a bit too annoying, offers to convert for loops to list comprehension
+    # , which may heart readability
+    "PERF401",
+
+    # suggests no using exception in for loops
+    # we do use this technique a lot, plus in 3.11 happy path exception handling is "zero-cost"
+    "PERF203",
 ]