Add legacy/v1 arithmetic convention with deprecation transition

.gitignore

@@ -50,4 +50,3 @@ benchmark/scripts/leftovers/
 # direnv
 .envrc
 AGENTS.md
-coverage.xml

linopy/__init__.py

@@ -13,7 +13,7 @@
 # we need to extend their __mul__ functions with a quick special case
 import linopy.monkey_patch_xarray  # noqa: F401
 from linopy.common import align
-from linopy.config import options
+from linopy.config import LinopyDeprecationWarning, options
 from linopy.constants import EQUAL, GREATER_EQUAL, LESS_EQUAL
 from linopy.constraints import Constraint, Constraints
 from linopy.expressions import LinearExpression, QuadraticExpression, merge
@@ -34,6 +34,7 @@
     "EQUAL",
     "GREATER_EQUAL",
     "LESS_EQUAL",
+    "LinopyDeprecationWarning",
     "LinearExpression",
     "Model",
     "Objective",

linopy/common.py

@@ -10,7 +10,7 @@
 import operator
 import os
 from collections.abc import Callable, Generator, Hashable, Iterable, Sequence
-from functools import reduce, wraps
+from functools import partial, reduce, wraps
 from pathlib import Path
 from typing import TYPE_CHECKING, Any, Generic, TypeVar, overload
 from warnings import warn
@@ -1205,7 +1205,7 @@ def check_common_keys_values(list_of_dicts: list[dict[str, Any]]) -> bool:
 
 def align(
     *objects: LinearExpression | QuadraticExpression | Variable | T_Alignable,
-    join: JoinOptions = "exact",
+    join: JoinOptions | None = None,
     copy: bool = True,
     indexes: Any = None,
     exclude: str | Iterable[Hashable] = frozenset(),
@@ -1265,41 +1265,56 @@ def align(
 
 
     """
+    from linopy.config import options
     from linopy.expressions import LinearExpression, QuadraticExpression
     from linopy.variables import Variable
 
-    # Extract underlying Datasets for index computation.
+    if join is None:
+        join = options["arithmetic_convention"]
+
+    if join == "legacy":
+        from linopy.config import LEGACY_DEPRECATION_MESSAGE, LinopyDeprecationWarning
+
+        warn(
+            LEGACY_DEPRECATION_MESSAGE,
+            LinopyDeprecationWarning,
+            stacklevel=2,
+        )
+        join = "inner"
+
+    elif join == "v1":
+        join = "exact"
+
+    finisher: list[partial[Any] | Callable[[Any], Any]] = []
     das: list[Any] = []
     for obj in objects:
-        if isinstance(obj, LinearExpression | QuadraticExpression | Variable):
+        if isinstance(obj, LinearExpression | QuadraticExpression):
+            finisher.append(partial(obj.__class__, model=obj.model))
+            das.append(obj.data)
+        elif isinstance(obj, Variable):
+            finisher.append(
+                partial(
+                    obj.__class__,
+                    model=obj.model,
+                    name=obj.data.attrs["name"],
+                    skip_broadcast=True,
+                )
+            )
             das.append(obj.data)
         else:
+            finisher.append(lambda x: x)
             das.append(obj)
 
     exclude = frozenset(exclude).union(HELPER_DIMS)
-
-    # Compute target indexes.
-    target_aligned = xr_align(
-        *das, join=join, copy=False, indexes=indexes, exclude=exclude
+    aligned = xr_align(
+        *das,
+        join=join,
+        copy=copy,
+        indexes=indexes,
+        exclude=exclude,
+        fill_value=fill_value,
     )
-
-    # Reindex each object to target indexes.
-    reindex_kwargs: dict[str, Any] = {}
-    if fill_value is not dtypes.NA:
-        reindex_kwargs["fill_value"] = fill_value
-    results: list[Any] = []
-    for obj, target in zip(objects, target_aligned):
-        indexers = {
-            dim: target.indexes[dim]
-            for dim in target.dims
-            if dim not in exclude and dim in target.indexes
-        }
-        # Variable.reindex has no fill_value — it always uses sentinels
-        if isinstance(obj, Variable):
-            results.append(obj.reindex(indexers))
-        else:
-            results.append(obj.reindex(indexers, **reindex_kwargs))  # type: ignore[union-attr]
-    return tuple(results)
+    return tuple([f(da) for f, da in zip(finisher, aligned)])
 
 
 LocT = TypeVar(

linopy/config.py

@@ -9,28 +9,46 @@
 
 from typing import Any
 
+VALID_ARITHMETIC_JOINS = {"legacy", "v1"}
+
+LEGACY_DEPRECATION_MESSAGE = (
+    "The 'legacy' arithmetic convention is deprecated and will be removed in "
+    "linopy v1. Set linopy.options['arithmetic_convention'] = 'v1' to opt in "
+    "to the new behavior, or filter this warning with:\n"
+    "  import warnings; warnings.filterwarnings('ignore', category=LinopyDeprecationWarning)"
+)
+
+
+class LinopyDeprecationWarning(FutureWarning):
+    """Warning for deprecated linopy features scheduled for removal."""
+
 
 class OptionSettings:
-    def __init__(self, **kwargs: int) -> None:
+    def __init__(self, **kwargs: Any) -> None:
         self._defaults = kwargs
         self._current_values = kwargs.copy()
 
-    def __call__(self, **kwargs: int) -> None:
+    def __call__(self, **kwargs: Any) -> None:
         self.set_value(**kwargs)
 
-    def __getitem__(self, key: str) -> int:
+    def __getitem__(self, key: str) -> Any:
         return self.get_value(key)
 
-    def __setitem__(self, key: str, value: int) -> None:
+    def __setitem__(self, key: str, value: Any) -> None:
         return self.set_value(**{key: value})
 
-    def set_value(self, **kwargs: int) -> None:
+    def set_value(self, **kwargs: Any) -> None:
         for k, v in kwargs.items():
             if k not in self._defaults:
                 raise KeyError(f"{k} is not a valid setting.")
+            if k == "arithmetic_convention" and v not in VALID_ARITHMETIC_JOINS:
+                raise ValueError(
+                    f"Invalid arithmetic_convention: {v!r}. "
+                    f"Must be one of {VALID_ARITHMETIC_JOINS}."
+                )
             self._current_values[k] = v
 
-    def get_value(self, name: str) -> int:
+    def get_value(self, name: str) -> Any:
         if name in self._defaults:
             return self._current_values[name]
         else:
@@ -57,4 +75,8 @@ def __repr__(self) -> str:
         return f"OptionSettings:\n {settings}"
 
 
-options = OptionSettings(display_max_rows=14, display_max_terms=6)
+options = OptionSettings(
+    display_max_rows=14,
+    display_max_terms=6,
+    arithmetic_convention="legacy",
+)