In almost all cases, if a memory allocation in our C & C++ code fails, the failure is handled so that eventually a MemoryError exception is raised by Python. I think that is a general rule that we apply to all low-level code: failure to allocate memory should ultimately result in a Python exception and not crash the interpreter.

Here are a few places where we don't check for a memory allocation failure:

• numpy/numpy/_core/src/multiarray/dtype_transfer.c

  Lines 171 to 173 in f39abd4

  	_any_to_object_auxdata *res = PyMem_Malloc(sizeof(_any_to_object_auxdata));
  	res->base = data->base;

• numpy/numpy/_core/src/multiarray/stringdtype/casts.cpp

  Lines 856 to 861 in f39abd4

  	char *buf = (char *)PyMem_RawCalloc(sizeof(char), plen + nlen + slen + 1);
  	// memcpy instead of strcpy/strncat to avoid stringop-truncation warning,
  	// since we are not including the trailing null character
  	char *p = buf;
  	memcpy(p, prefix, plen);

• numpy/numpy/_core/src/multiarray/stringdtype/casts.cpp

  Lines 1117 to 1118 in f39abd4

  	char *buf = (char *)PyMem_RawMalloc(s.size + 1);
  	memcpy(buf, s.buf, s.size);

• numpy/numpy/_core/src/umath/stringdtype_ufuncs.cpp

  Line 1121 in f39abd4

  char *new_buf = (char *)PyMem_RawCalloc(s1.size, 1);

• numpy/numpy/_core/src/umath/stringdtype_ufuncs.cpp

  Line 1243 in f39abd4

  char *new_buf = (char *)PyMem_RawCalloc(s.size, 1);

• numpy/numpy/_core/src/umath/stringdtype_ufuncs.cpp

  Line 1458 in f39abd4

  char *new_buf = (char *)PyMem_RawCalloc(max_size, 1);

• numpy/numpy/_core/src/umath/stringdtype_ufuncs.cpp

  Line 1577 in f39abd4

  char *new_buf = (char *)PyMem_RawCalloc(new_buf_size, 1);

The following uses of std::unordered_set in unique.cpp can throw an exception if an allocation fails, which will crash Python:

• numpy/numpy/_core/src/multiarray/unique.cpp

  Lines 212 to 214 in f39abd4

  	std::unordered_set<T *, decltype(hash), decltype(equal)> hashset(
  	std::min(isize, (npy_intp)HASH_TABLE_INITIAL_BUCKETS), hash, equal
  	);

• numpy/numpy/_core/src/multiarray/unique.cpp

  Line 220 in f39abd4

  hashset.insert((T *)idata);

(This was not an exhaustive search.)