ENH: Implement concatenate dtype and casting keyword arguments

Unfortunately, the casting was not consistent and sometimes used
force casting (axis=None) while normally same kind casting was used.
This thus deprecates the `force_casting` corner case, so that
casting has to be provided in the future.

2 files changed, 14 insertions, 0 deletions

diff --git a/doc/release/upcoming_changes/16134.compatibility.rst b/doc/release/upcoming_changes/16134.compatibility.rst
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index 000000000..4270ea271
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+++ b/doc/release/upcoming_changes/16134.compatibility.rst
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+Same kind casting in concatenate with ``axis=None``
+---------------------------------------------------
+Unlike most `~numpy.concatenate` calls, when no axis
+was given (the ravelled arrays being concatenated)
+previously "unsafe" casting was used.
+This is now deprecated and "same kind" casting will be
+used by default. The new ``casting`` keyword argument
+can be used to retain the old behaviour.
diff --git a/doc/release/upcoming_changes/16134.improvement.rst b/doc/release/upcoming_changes/16134.improvement.rst
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index 000000000..0699f44bd
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+Concatenate supports providing an output dtype
+----------------------------------------------
+Support was added to `~numpy.concatenate` to provide
+an output ``dtype`` and ``casting`` using keyword
+arguments. The ``dtype`` argument cannot be provided
+in conjunction with the ``out`` one.