Fix test failures with newer msvc compilers (related to string aliasing)

src/ripple/rpc/impl/RPCHelpers.cpp

@@ -696,19 +696,31 @@ parseRippleLibSeed(Json::Value const& value)
 std::optional<Seed>
 getSeedFromRPC(Json::Value const& params, Json::Value& error)
 {
-    // The array should be constexpr, but that makes Visual Studio unhappy.
-    static char const* const seedTypes[]{
-        jss::passphrase.c_str(), jss::seed.c_str(), jss::seed_hex.c_str()};
+    using string_to_seed_t =
+        std::function<std::optional<Seed>(const std::string&)>;
+    using seed_match_t = std::pair<const char*, string_to_seed_t>;
+
+    static seed_match_t const seedTypes[]{
+        {jss::passphrase.c_str(),
+         [](const std::string& s) { return parseGenericSeed(s); }},
+        {jss::seed.c_str(),
+         [](const std::string& s) { return parseBase58<Seed>(s); }},
+        {jss::seed_hex.c_str(), [](const std::string& s) {
+             uint128 i;
+             if (i.parseHex(s))
+                 return std::optional<Seed>(Slice(i.data(), i.size()));
+             return std::optional<Seed>{};
+         }}};
 
     // Identify which seed type is in use.
-    char const* seedType = nullptr;
+    const seed_match_t* seedType = nullptr;
     int count = 0;
-    for (auto t : seedTypes)
+    for (auto const& t : seedTypes)
     {
-        if (params.isMember(t))
+        if (params.isMember(t.first))
         {
             ++count;
-            seedType = t;
+            seedType = &t;
         }
     }
 
@@ -722,28 +734,17 @@ getSeedFromRPC(Json::Value const& params, Json::Value& error)
     }
 
     // Make sure a string is present
-    if (!params[seedType].isString())
+    const auto& param = params[seedType->first];
+    if (!param.isString())
     {
-        error = RPC::expected_field_error(seedType, "string");
+        error = RPC::expected_field_error(seedType->first, "string");
         return std::nullopt;
     }
 
-    auto const fieldContents = params[seedType].asString();
+    auto const fieldContents = param.asString();
 
     // Convert string to seed.
-    std::optional<Seed> seed;
-
-    if (seedType == jss::seed.c_str())
-        seed = parseBase58<Seed>(fieldContents);
-    else if (seedType == jss::passphrase.c_str())
-        seed = parseGenericSeed(fieldContents);
-    else if (seedType == jss::seed_hex.c_str())
-    {
-        uint128 s;
-
-        if (s.parseHex(fieldContents))
-            seed.emplace(Slice(s.data(), s.size()));
-    }
+    std::optional<Seed> seed = seedType->second(fieldContents);
 
     if (!seed)
         error = rpcError(rpcBAD_SEED);
@@ -757,7 +758,6 @@ keypairForSignature(Json::Value const& params, Json::Value& error)
     bool const has_key_type = params.isMember(jss::key_type);
 
     // All of the secret types we allow, but only one at a time.
-    // The array should be constexpr, but that makes Visual Studio unhappy.
     static char const* const secretTypes[]{
         jss::passphrase.c_str(),
         jss::secret.c_str(),
@@ -811,7 +811,8 @@ keypairForSignature(Json::Value const& params, Json::Value& error)
             return {};
         }
 
-        if (secretType == jss::secret.c_str())
+        // using strcmp as pointers may not match (see  https://bit.ly/3OGvf0E)
+        if (strcmp(secretType, jss::secret.c_str()) == 0)
         {
             error = RPC::make_param_error(
                 "The secret field is not allowed if " +
@@ -823,7 +824,8 @@ keypairForSignature(Json::Value const& params, Json::Value& error)
     // ripple-lib encodes seed used to generate an Ed25519 wallet in a
     // non-standard way. While we never encode seeds that way, we try
     // to detect such keys to avoid user confusion.
-    if (secretType != jss::seed_hex.c_str())
+    // using strcmp as pointers may not match (see  https://bit.ly/3OGvf0E)
+    if (strcmp(secretType, jss::seed_hex.c_str()) != 0)
     {
         seed = RPC::parseRippleLibSeed(params[secretType]);