Fixed a warning that was coming up for vector<unsigned char> fill

[mxaddict]

This fixes a warning during build:

In file included from /usr/include/c++/14.1.1/string:51,
                 from ./crypto/sha256.h:10,
                 from ./hash.h:12,
                 from ./blsct/arith/mcl/mcl_scalar.h:15,
                 from ./blsct/arith/mcl/mcl_g1point.h:12,
                 from ./blsct/arith/mcl/mcl.h:12,
                 from ./blsct/double_public_key.h:8,
                 from ./addresstype.h:9,
                 from ./wallet/wallet.h:9,
                 from wallet/test/wallet_tests.cpp:5:
In function ‘constexpr typename __gnu_cxx::__enable_if<std::__is_scalar<_Tp>::__value, void>::__type std::__fill_a1(_ForwardIterator, _ForwardIterator, const _Tp&) [with _ForwardIterator = unsigned char*; _Tp = int]’,
    inlined from ‘constexpr void std::__fill_a1(__gnu_cxx::__normal_iterator<_Iterator, _Container>, __gnu_cxx::__normal_iterator<_Iterator, _Container>, const _Tp&) [with _Ite = unsigned char*; _Cont = vector<unsigned char>; _Tp = int]’ at /usr/include/c++/14.1.1/bits/stl_algobase.h:981:21,
    inlined from ‘constexpr void std::__fill_a(_FIte, _FIte, const _Tp&) [with _FIte = __gnu_cxx::__normal_iterator<unsigned char*, vector<unsigned char> >; _Tp = int]’ at /usr/include/c++/14.1.1/bits/stl_algobase.h:998:21,
    inlined from ‘constexpr void std::fill(_ForwardIterator, _ForwardIterator, const _Tp&) [with _ForwardIterator = __gnu_cxx::__normal_iterator<unsigned char*, vector<unsigned char> >; _Tp = int]’ at /usr/include/c++/14.1.1/bits/stl_algobase.h:1029:20,
    inlined from ‘void wallet::wallet_tests::PollutePubKey(CPubKey&)’ at wallet/test/wallet_tests.cpp:502:14:
/usr/include/c++/14.1.1/bits/stl_algobase.h:952:18: warning: ‘void* __builtin_memset(void*, int, long unsigned int)’ specified bound 18446744073709551615 exceeds maximum object size 9223372036854775807 [-Wstringop-overflow=]
  952 |         *__first = __tmp;
      |         ~~~~~~~~~^~~~~~~

[mxaddict]

This PR should be ready to review/merge

[gogoex]

Just out of curiosity, does the warning disappear if you:

• only add the assert line at the beginning and doesn't change anything and/or
• typecast 0 in the fill method to unsigned char i.e. static_cast<unsigned char>(0)
  ?

[mxaddict]

Just out of curiosity, does the warning disappear if you:

• only add the assert line at the beginning and doesn't change anything and/or
• typecast 0 in the fill method to unsigned char i.e. static_cast<unsigned char>(0)
  ?

I'm not 100% sure, but the fix I've implemented is from upstream bitcoin repo 😄

[gogoex]

Just out of curiosity, does the warning disappear if you:

• only add the assert line at the beginning and doesn't change anything and/or
• typecast 0 in the fill method to unsigned char i.e. static_cast<unsigned char>(0)
  ?

I'm not 100% sure, but the fix I've implemented is from upstream bitcoin repo 😄

Ah. I see 😁

[gogoex]

I think this change is reasonable.