Allow limit=None (sort of) but not offset=None.

We mixed up which of these should be allowed to be None in the old
interface, but we don't need to repeat the mistake in the new one,
though some of the fix will have to wait until new interfaces stop
delegating to the old ones.

python/lsst/daf/butler/_butler.py

@@ -1382,7 +1382,7 @@ def _query_data_ids(
         expanded: bool = False,
         order_by: Iterable[str] | str | None = None,
         limit: int | None = None,
-        offset: int | None = None,
+        offset: int = 0,
         explain: bool = True,
         **kwargs: Any,
     ) -> list[DataCoordinate]:
@@ -1569,7 +1569,7 @@ def _query_dimension_records(
         bind: Mapping[str, Any] | None = None,
         order_by: Iterable[str] | str | None = None,
         limit: int | None = None,
-        offset: int | None = None,
+        offset: int = 0,
         explain: bool = True,
         **kwargs: Any,
     ) -> list[DimensionRecord]:

python/lsst/daf/butler/_query_results.py

@@ -389,17 +389,16 @@ def order_by(self, *args: str) -> DataCoordinateQueryResults:
         raise NotImplementedError()
 
     @abstractmethod
-    def limit(self, limit: int, offset: int | None = 0) -> DataCoordinateQueryResults:
+    def limit(self, limit: int | None = None, offset: int = 0) -> DataCoordinateQueryResults:
         """Make the iterator return limited number of records.
 
         Parameters
         ----------
-        limit : `int`
+        limit : `int` or `None`, optional
             Upper limit on the number of returned records.
-        offset : `int` or `None`, optional
+        offset : `int`, optional
             The number of records to skip before returning at most ``limit``
-            records.  `None` is interpreted the same as zero for backwards
-            compatibility.
+            records.
 
         Returns
         -------
@@ -695,17 +694,16 @@ def order_by(self, *args: str) -> DimensionRecordQueryResults:
         raise NotImplementedError()
 
     @abstractmethod
-    def limit(self, limit: int, offset: int | None = 0) -> DimensionRecordQueryResults:
+    def limit(self, limit: int | None = None, offset: int = 0) -> DimensionRecordQueryResults:
         """Make the iterator return limited number of records.
 
         Parameters
         ----------
-        limit : `int`
+        limit : `int` or `None`, optional
             Upper limit on the number of returned records.
-        offset : `int` or `None`
+        offset : `int`, optional
             The number of records to skip before returning at most ``limit``
-            records.  `None` is interpreted the same as zero for backwards
-            compatibility.
+            records.
 
         Returns
         -------

python/lsst/daf/butler/direct_butler.py

@@ -2228,7 +2228,7 @@ def _query_data_ids(
         expanded: bool = False,
         order_by: Iterable[str] | str | None = None,
         limit: int | None = None,
-        offset: int | None = None,
+        offset: int = 0,
         explain: bool = True,
         **kwargs: Any,
     ) -> list[DataCoordinate]:
@@ -2289,7 +2289,7 @@ def _query_dimension_records(
         bind: Mapping[str, Any] | None = None,
         order_by: Iterable[str] | str | None = None,
         limit: int | None = None,
-        offset: int | None = None,
+        offset: int = 0,
         explain: bool = True,
         **kwargs: Any,
     ) -> list[DimensionRecord]:

python/lsst/daf/butler/direct_query_results.py

@@ -143,8 +143,10 @@ def order_by(self, *args: str) -> DataCoordinateQueryResults:
         # Docstring inherited.
         return DirectDataCoordinateQueryResults(self._registry_query_result.order_by(*args))
 
-    def limit(self, limit: int, offset: int | None = 0) -> DataCoordinateQueryResults:
+    def limit(self, limit: int | None = None, offset: int = 0) -> DataCoordinateQueryResults:
         # Docstring inherited.
+        if limit is None:
+            raise NotImplementedError("Offset without limit is temporarily unsupported.")
         return DirectDataCoordinateQueryResults(self._registry_query_result.limit(limit, offset))
 
 
@@ -289,8 +291,10 @@ def order_by(self, *args: str) -> DimensionRecordQueryResults:
         # Docstring inherited.
         return DirectDimensionRecordQueryResults(self._registry_query_result.order_by(*args))
 
-    def limit(self, limit: int, offset: int | None = 0) -> DimensionRecordQueryResults:
+    def limit(self, limit: int | None = None, offset: int = 0) -> DimensionRecordQueryResults:
         # Docstring inherited.
+        if limit is None:
+            raise NotImplementedError("Offset without limit is temporarily unsupported.")
         return DirectDimensionRecordQueryResults(self._registry_query_result.limit(limit, offset))
 
     def explain_no_results(self, execute: bool = True) -> Iterable[str]: