Merge bitcoin#30131: wallet, tests: Avoid stringop-overflow warning in PollutePubKey

2289d45 wallet, tests: Avoid stringop-overflow warning in PollutePubKey (Ava Chow)

Pull request description:

  Fixes  bitcoin#30114

ACKs for top commit:
  maflcko:
    ACK 2289d45 with g++ 14.1.1 🦄
  theStack:
    utACK 2289d45
  laanwj:
    ACK 2289d45

Tree-SHA512: 173c3c299bdd890f73e8a67a37880dbf816265e8b3c8298557ef2fc4670f5447005c0d2d81726f9bc43f6a69d677365d90a604354b3cbab0e3c52c4526d0407e

Author: fanquake

src/wallet/test/wallet_tests.cpp

@@ -499,8 +499,10 @@ static void TestWatchOnlyPubKey(LegacyScriptPubKeyMan* spk_man, const CPubKey& a
 // Cryptographically invalidate a PubKey whilst keeping length and first byte
 static void PollutePubKey(CPubKey& pubkey)
 {
-    std::vector<unsigned char> pubkey_raw(pubkey.begin(), pubkey.end());
-    std::fill(pubkey_raw.begin()+1, pubkey_raw.end(), 0);
+    assert(pubkey.size() >= 1);
+    std::vector<unsigned char> pubkey_raw;
+    pubkey_raw.push_back(pubkey[0]);
+    pubkey_raw.insert(pubkey_raw.end(), pubkey.size() - 1, 0);
     pubkey = CPubKey(pubkey_raw);
     assert(!pubkey.IsFullyValid());
     assert(pubkey.IsValid());