vutils/system_allocator: Always return NULL on zero-size realloc#145
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`sys_malloc` and `sys_calloc` already short-circuit to NULL when `bytes * times == 0`, but `sys_realloc` was forwarding straight to libc `realloc(ptr, 0)`, whose behavior is implementation-defined (and undefined as of C23). On macOS that returns a valid 1-byte allocation, so the existing zero-size realloc test asserted NULL and failed. Mirror the malloc/calloc guard in `sys_realloc`, also freeing the old buffer to avoid leaking it when the caller shrinks to zero. The arena backend already returns NULL in this case, so vut_allocator_realloc is now consistent across both backends and all platforms.
JeanJPNM
approved these changes
Jun 13, 2026
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sys_mallocandsys_callocalready short-circuit to NULL whenbytes * times == 0, butsys_reallocwas forwarding straight to libcrealloc(ptr, 0), whose behavior is implementation-defined (and undefined as of C23). On macOS that returns a valid 1-byte allocation, so the existing zero-size realloc test asserted NULL and failed.Mirror the malloc/calloc guard in
sys_realloc, also freeing the old buffer to avoid leaking it when the caller shrinks to zero. The arena backend already returns NULL in this case, so vut_allocator_realloc is now consistent across both backends and all platforms.