Make decode_hash(1) throw, prevents null_hash when invalid.

Author: evoskuil

include/bitcoin/system/impl/radix/base_16.ipp

@@ -194,11 +194,11 @@ constexpr bool decode_hash(data_array<Size>& out,
 }
 
 template <size_t Size>
-constexpr data_array<Size> decode_hash(const std::string_view& in) NOEXCEPT
+constexpr data_array<Size> decode_hash(const std::string_view& in) THROWS
 {
     data_array<Size> out{};
     if (!decode_hash(out, in))
-        return {};
+        throw istream_exception{ "decode_hash" };
 
     return out;
 }

include/bitcoin/system/radix/base_16.hpp

@@ -69,9 +69,9 @@ template <size_t Size>
 constexpr bool decode_hash(data_array<Size>& out,
     const std::string_view& in) NOEXCEPT;
 
-/// Returns null_hash on error.
+/// Throws istream_exception on input error.
 template <size_t Size>
-constexpr data_array<Size> decode_hash(const std::string_view& in) NOEXCEPT;
+constexpr data_array<Size> decode_hash(const std::string_view& in) THROWS;
 
 /// Literal decodings of hex string, errors reflected as zero-filled data.
 /// ---------------------------------------------------------------------------