From 096f9b04e9abf666e442f6cfd87b18c9395bc157 Mon Sep 17 00:00:00 2001
From: Hameer Abbasi <2190658+hameerabbasi@users.noreply.github.com>
Date: Sat, 1 Jul 2023 08:15:17 +0200
Subject: [PATCH] Fix upcast on in-place. (#598)

---
 sparse/_sparse_array.py       | 11 +++++++++++
 sparse/tests/test_elemwise.py |  7 +++++++
 2 files changed, 18 insertions(+)

diff --git a/sparse/_sparse_array.py b/sparse/_sparse_array.py
index 8bd5db62..546addc7 100644
--- a/sparse/_sparse_array.py
+++ b/sparse/_sparse_array.py
@@ -289,6 +289,17 @@ def __array_ufunc__(self, ufunc, method, *inputs, **kwargs):
             )
 
         if out is not None:
+            test_args = [
+                np.empty(1, dtype=a.dtype) if hasattr(a, "dtype") else [a]
+                for a in inputs
+            ]
+            test_kwargs = kwargs.copy()
+            if method == "reduce":
+                test_kwargs["axis"] = None
+            test_out = tuple(np.empty(1, dtype=a.dtype) for a in out)
+            if len(test_out) == 1:
+                test_out = test_out[0]
+            getattr(ufunc, method)(*test_args, out=test_out, **test_kwargs)
             kwargs["dtype"] = out[0].dtype
 
         if method == "outer":
diff --git a/sparse/tests/test_elemwise.py b/sparse/tests/test_elemwise.py
index 746cbeb0..86cd6a05 100644
--- a/sparse/tests/test_elemwise.py
+++ b/sparse/tests/test_elemwise.py
@@ -720,3 +720,10 @@ def test_no_deprecation_warning():
     a = np.array([1, 2])
     s = sparse.COO(a, a, shape=(3,))
     s == s
+
+
+# Regression test for gh-587
+def test_no_out_upcast():
+    a = sparse.COO([[0, 1], [0, 1]], [1, 1], shape=(2, 2))
+    with pytest.raises(TypeError):
+        a *= 0.5