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BUG: reshape accept an empty array and copy=False #232

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Merged
ev-br merged 2 commits into from
Jul 28, 2026
+14 −3
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BUG: reshape accept an empty array and copy=False #232

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c075acf
fix: accept an empty view without a copy
stanbot8 Jul 28, 2026
c51195c
Update array_api_strict/_manipulation_functions.py
ev-br Jul 28, 2026
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5 changes: 3 additions & 2 deletions array_api_strict/_manipulation_functions.py
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Original file line number Diff line number Diff line change
Expand Up @@ -122,8 +122,9 @@ def reshape(x: Array, /, shape: tuple[int, ...], *, copy: bool | None = None) ->

reshaped = np.reshape(data, shape)

if copy is False and not np.shares_memory(data, reshaped):
raise AttributeError("Incompatible shape for in-place modification.")
# NB: `.size>0` works around that `x=np.asarray([]); np.shares_memory(x, x)` is False
if copy is False and data.size > 0 and not np.shares_memory(data, reshaped):
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raise ValueError("Incompatible shape for a no-copy reshape.")

return Array._new(reshaped, device=x.device)

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12 changes: 11 additions & 1 deletion array_api_strict/tests/test_manipulation_functions.py
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Expand Up @@ -32,5 +32,15 @@ def test_reshape_copy():

a = asarray(np.ones((2, 3)).T)
b = reshape(a, (3, 2), copy=True)
assert_raises(AttributeError, lambda: reshape(a, (2, 3), copy=False))
assert_raises(ValueError, lambda: reshape(a, (2, 3), copy=False))

@ev-br ev-br Jul 28, 2026

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Strictly speaking, a back-compat break. That said, there is no reason for an AttributeError here, and the spec says ValueError, https://data-apis.org/array-api/2022.12/API_specification/generated/array_api.reshape.html



def test_reshape_copy_false_keeps_an_empty_view():
a = asarray(np.empty((0,)))
b = reshape(a, (0, 2), copy=False)
assert b.shape == (0, 2)

a = asarray(np.empty((0, 2)))
b = reshape(a, (2, 0), copy=False)
assert b.shape == (2, 0)

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