gh-114329: Add PyList_GetItemRef function#114504
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The new `PyList_GetItemRef` is similar to `PyList_GetItem`, but returns a strong reference instead of a borrowed reference. Additionally, if the passed "list" object is not a list, the function sets a `TypeError` instead of calling `PyErr_BadInternalCall()`.
When I proposed such change, @serhiy-storchaka asked me to stick to |
Doc/c-api/list.rst
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| :exc:`TypeError` exception. | ||
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| This behaves like :c:func:`PyList_GetItem`, but returns a | ||
| :term:`strong reference` instead of a :term:`borrowed reference`. |
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I suggest to make this function the new reference, and document PyList_GetItem() as: "Similar to PyList_GetItemRef(), but return a borrowed reference".
Lib/test/test_capi/test_list.py
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| # CRASHES get_item(21, 2) | ||
| # CRASHES get_item(NULL, 1) | ||
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| def test_list_get_item_ref(self): |
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Can you share most code between test_list_get_item() and test_list_get_item_ref()?
Misc/stable_abi.toml
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| [function.PyList_GetItemRef] | ||
| added = '3.13' |
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Move it to the end of the file.
Is it RuntimeError or SystemError? The only discussed difference was returning a strong reference instead of a weak reference. If we want to change also the exception type, it should be a separate discussion. Most concrete type C API raises SystemError if they are called with wrong type. It is considered a programming error, not a data error. |
I suggest to document that the function "parameter must be list" , without mentioning the exact exception type. |
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I've removed the sentence mentioning |
vstinner
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vstinner
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LGTM.
The TypeError behavior is explicitly stated in the C API WG capi-workgroup/decisions#9 (comment). See also capi-workgroup/api-evolution#29 (comment) and PyWeakref_GetRef().
Oh ok, I didn't notice that TypeError was explicitly mentioned.
corona10
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corona10
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LGTM too.
I will merge the PR if @serhiy-storchaka approve.
encukou
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encukou
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If the WG does discuss the exception type, it'll take some time.
Let's merge this, the type can be changed later
Co-authored-by: Erlend E. Aasland <[email protected]>
The new `PyList_GetItemRef` is similar to `PyList_GetItem`, but returns a strong reference instead of a borrowed reference. Additionally, if the passed "list" object is not a list, the function sets a `TypeError` instead of calling `PyErr_BadInternalCall()`.
The new `PyList_GetItemRef` is similar to `PyList_GetItem`, but returns a strong reference instead of a borrowed reference. Additionally, if the passed "list" object is not a list, the function sets a `TypeError` instead of calling `PyErr_BadInternalCall()`.
6 participants
The new
PyList_GetItemRefis similar toPyList_GetItem, but returns a strong reference instead of a borrowed reference. Additionally, if the passed "list" object is not a list, the function sets aTypeErrorinstead of callingPyErr_BadInternalCall().PyList_GetItemRef, a variant ofPyList_GetItemthat returns a strong reference #114329📚 Documentation preview 📚: https://cpython-previews--114504.org.readthedocs.build/