Incorrect BIP49 P2SH-P2WPKH address

[3tbraden]

Describe the bug
TWBitcoinAddressCreateWithPublicKey with TWCoinTypeP2shPrefix(TWCoinTypeBitcoin) does not product the correct address. With public key 03b54d899b0760164100601571f783a99a8d456975a70303d14a4828882a118de9, I got 3FNHEJmrBdBDpQn1PfjB1qhsXWJUeygQzP instead of 3GMJNpE5Xj44YEJbNskyHLVQkd8DV7GDCE.

To Reproduce

TEST(TWBitcoinAddress, CreateP2SHWithPublicKey) {
    const auto pubKey = WRAP(TWPublicKey, TWPublicKeyCreateWithData(DATA("03b54d899b0760164100601571f783a99a8d456975a70303d14a4828882a118de9").get(), TWPublicKeyTypeSECP256k1));
    EXPECT_TRUE(pubKey != nullptr);
    const auto addr = WRAP(TWBitcoinAddress, TWBitcoinAddressCreateWithPublicKey(pubKey.get(), TWCoinTypeP2shPrefix(TWCoinTypeBitcoin)));
    EXPECT_TRUE(addr.get() != nullptr);
    EXPECT_EQ(std::string(TWStringUTF8Bytes(TWBitcoinAddressDescription(addr.get()))), "3GMJNpE5Xj44YEJbNskyHLVQkd8DV7GDCE");
}

Expected behavior
I used the above code to test BIP49 address generation, public key from the mnemonic left already pipe and derivation path m/49'/0'/0'/0/0, and expected address to be 3GMJNpE5Xj44YEJbNskyHLVQkd8DV7GDCE as verified from iancoleman.io and electrum wallet.

Screenshots

[optout21]

Creating address from public key is a simple hash, it has nothing to do with mnemonic or derivation path.
Sh prefix for bitcoin is 5.
I don't know how did you derived the expected address.
With the given 3-word mnemonic (invalid, BTW), I don't see the same public key in https://iancoleman.io/bip39/.
Please be more specific.

[3tbraden]

it is the public key for that address which I got from the mnemonic and the derivation path on iancoleman.

[optout21]

If you check iancoleman, for BIP49 it uses P2wpkhInP2sh; see
https://github.com/iancoleman/bip39/blob/master/src/js/index.js#L1382
Address is not derived from pubkey directly, but from script.
I believe these steps can be also done using wallet-core functions (Script, hash, ...)
Note that for BTC, TrustWallet uses BIP84 format ('bc1...')

[3tbraden]

Thank you for the insight, it's very helpful. So I looked up how BIP49 addresses are generated and come up with the code that I am posting as the answer here(I am actually working with golang). Basically I have to prepare the key hash and script data and generate the address from it with a designated prefix.

[3tbraden]

pubKeyHashData := C.TWHashSHA256RIPEMD(C.TWPublicKeyData(pub))
redeemScriptBytes := []byte{}
redeemScriptBytes = append(redeemScriptBytes, 0x00, 0x00)
redeemScriptBytes[1] = 0x14
redeemScriptBytes = append(redeemScriptBytes, TWDataGoBytes(pubKeyHashData)...)
addrBytes := C.TWHashSHA256RIPEMD(TWDataCreateWithGoBytes(redeemScriptBytes))
data := []byte{}
data = append(data, 0x05)
data = append(data, TWDataGoBytes(addrBytes)...)
p2shp2wpkhAddr := C.TWBitcoinAddressCreateWithData(TWDataCreateWithGoBytes(data))