gh-148573: correct allocation of complex types in the ctypes#148579
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skirpichev wants to merge 4 commits intopython:mainfrom
Open
gh-148573: correct allocation of complex types in the ctypes#148579skirpichev wants to merge 4 commits intopython:mainfrom
skirpichev wants to merge 4 commits intopython:mainfrom
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Old code relying on implementation detail, that elements[1] for the FFI_TYPE_COMPLEX was never read. But this type actually shares same assumption as the FFI_TYPE_STRUCT: the elements field is a NULL-terminated array of pointers to ffi_type objects. So far for primitive types - only complex types have this struct field as non-NULL (two element array).
sunmy2019
reviewed
Apr 15, 2026
Co-authored-by: sunmy2019 <59365878+sunmy2019@users.noreply.github.com>
sunmy2019
approved these changes
Apr 15, 2026
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Should we add news for this? |
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I don't think it's a user-visible change. |
encukou
approved these changes
Apr 16, 2026
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| /* From primitive types - only complex types have the elements | ||
| struct field as non-NULL (two element array). */ | ||
| assert(fmt->pffi_type->type == FFI_TYPE_COMPLEX); |
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Thanks! There's one more check we can do here.
Suggested change
| /* From primitive types - only complex types have the elements | |
| struct field as non-NULL (two element array). */ | |
| assert(fmt->pffi_type->type == FFI_TYPE_COMPLEX); | |
| /* From primitive types - only complex types have the elements struct | |
| field as non-NULL (two element array, including final NULL). */ | |
| assert(fmt->pffi_type->type == FFI_TYPE_COMPLEX); | |
| assert(fmt->pffi_type->elements[1] == NULL); |
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If that's needed, how about using the same check in libffi, i.e.
a->elements != NULL && a->elements[0] != NULL && a->elements[1] == NULL
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Old code relying on implementation detail, that elements[1] for the FFI_TYPE_COMPLEX was never read.
But this type actually shares same assumption as the FFI_TYPE_STRUCT: the elements field is a NULL-terminated array of pointers to ffi_type objects. So far for primitive types - only complex types have this struct field as non-NULL (two element array).
_ctypesbreaks libffi's NULL-terminatedelementsinvariant for complex types #148573