[pull] main from pydata:main

.pre-commit-config.yaml

@@ -24,7 +24,7 @@ repos:
       - id: rst-inline-touching-normal
       - id: text-unicode-replacement-char
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.15.4
+    rev: v0.15.9
     hooks:
       - id: ruff-check
         args: ["--fix", "--show-fixes"]
@@ -42,7 +42,7 @@ repos:
       - id: prettier
         args: ["--cache-location=.prettier_cache/cache"]
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.19.1
+    rev: v1.20.0
     hooks:
       - id: mypy
         # Copied from setup.cfg
@@ -76,7 +76,7 @@ repos:
       - id: validate-pyproject
         additional_dependencies: ["validate-pyproject-schema-store[all]"]
   - repo: https://github.com/adhtruong/mirrors-typos
-    rev: v1.44.0
+    rev: v1.45.0
     hooks:
       - id: typos
   - repo: https://github.com/zizmorcore/zizmor-pre-commit

doc/whats-new.rst

@@ -186,6 +186,11 @@ Breaking Changes
   not intended to be visible to end-users so this version of xarray
   switches to using ``FutureWarning`` everywhere (:pull:`11112`).
   By `Julia Signell <https://github.com/jsignell>`_.
+- Passing a :py:class:`Dataset` as ``data_vars`` to the :py:class:`Dataset`
+  constructor now raises :py:class:`TypeError`. This was never intended behavior
+  and silently dropped ``attrs``. Use :py:meth:`Dataset.copy` instead
+  (:issue:`11095`).
+  By `Kristian Kollsga <https://github.com/kkollsga>`_.
 
 Bug Fixes
 ~~~~~~~~~

pyproject.toml

@@ -398,7 +398,8 @@ aso = "aso"
 # Technical terms
 nd = "nd"
 nin = "nin"
-nclusive = "nclusive" # part of "inclusive" in error messages
+nclusive = "nclusive"   # part of "inclusive" in error messages
+writeable = "writeable"
 
 # Variable names
 ba = "ba"
@@ -407,6 +408,7 @@ fo = "fo"
 iy = "iy"
 vart = "vart"
 ede = "ede"
+WRITEABLE = "WRITEABLE"
 
 # Organization/Institution names
 Stichting = "Stichting"

xarray/core/dataset.py

@@ -385,6 +385,11 @@ def __init__(
     ) -> None:
         if data_vars is None:
             data_vars = {}
+        if isinstance(data_vars, Dataset):
+            raise TypeError(
+                "Passing a Dataset as `data_vars` to the Dataset constructor is"
+                " not supported. Use `ds.copy()` to create a copy of a Dataset."
+            )
         if coords is None:
             coords = {}
 

xarray/tests/test_dataset.py

@@ -494,6 +494,14 @@ def test_constructor(self) -> None:
         actual = Dataset({"z": expected["z"]})
         assert_identical(expected, actual)
 
+    def test_constructor_dataset_as_data_vars_raises(self) -> None:
+        ds = Dataset({"x": ("x", [1, 2, 3])}, attrs={"key": "value"})
+        with pytest.raises(
+            TypeError,
+            match=r"Passing a Dataset as `data_vars`.*Use `ds\.copy\(\)`",
+        ):
+            Dataset(ds)
+
     def test_constructor_1d(self) -> None:
         expected = Dataset({"x": (["x"], 5.0 + np.arange(5))})
         actual = Dataset({"x": 5.0 + np.arange(5)})