BUG (string dtype): fix inplace mutation with copy=False in ensure_string_array #59756
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| result = result.copy() | ||
| elif not copy and result is arr: | ||
| already_copied = False | ||
| if result is arr or np.may_share_memory(arr, result): |
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any particular reason for may_share_memory instead of shares_memory?
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Because that is what was recommended by the numpy developer: #54654 (comment)
My understanding is that we have here either always a full copy or either exactly the same memory, so just checking the bounds should be sufficient, and there is less risk to this being a costly check (although I don't really know how this works under the hood, so not sure if there is any risk in practice)
| base_copy.astype(any_string_dtype) | ||
| tm.assert_series_equal(base, base_copy) | ||
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| @td.skip_if_no("pyarrow") |
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is this decorator now redundant?
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Yes, indeed, thanks
| @@ -120,14 +120,23 @@ def test_astype_string_copy_on_pickle_roundrip(): | |||
| tm.assert_series_equal(base, base_copy) | |||
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| def test_astype_string_copy_on_pickle_roundrip(any_string_dtype): | |||
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i cant find it now, but i thought one of the various string-dtype-like fixtures included str, which would let us de-duplicate this test with the previous one
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The string_dtype fixture has that, but that fixture doesn't have all the other variants. After 3.0, the astype(str) will be equivalent to astype(pd.StringDtype(na_value=np.nan)) and then the above test will be superfluous, but at the moment astype(str) still does something specfic (do convert to string but end up in object dtype)
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Will add a comment
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small questions, otherwise LGTM |
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Thanks @jorisvandenbossche |
…ring_array (pandas-dev#59756) (#2) * BUG (string dtype): fix inplace mutation with copy=False in ensure_string_array * update Co-authored-by: Joris Van den Bossche <jorisvandenbossche@gmail.com>
…ring_array (pandas-dev#59756) * BUG (string dtype): fix inplace mutation with copy=False in ensure_string_array * update
…ring_array (pandas-dev#59756) * BUG (string dtype): fix inplace mutation with copy=False in ensure_string_array * update
…ring_array (#59756) * BUG (string dtype): fix inplace mutation with copy=False in ensure_string_array * update
Further follow-up on #54654, #54687, #57212, because we still had the issue when
copy=Falsewas passed (which happens when casting to any of the string dtypes).The added tests failed without the actual code change.
(smaller change extracted from #59685)
xref #54792