MOD: Improve Python record enum field getters

Author: threecgreen

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## 0.43.0 - TBD
 
+### Enhancements
+- Made `Unset` a fully-supported variant of `SystemCode` and `ErrorCode`
+
 ### Breaking changes
 - Removed `mode` parameter in `Historical::MetadataGetCost()`
 

include/databento/enums.hpp

@@ -609,6 +609,8 @@ enum ErrorCode : std::uint8_t {
   InvalidSubscription = 5,
   // An error occurred in the gateway.
   InternalError = 6,
+  // No error code was specified or this record was upgraded from a version 1 struct
+  // where the code field didn't exist.
   Unset = 255,
 };
 }  // namespace error_code
@@ -630,6 +632,8 @@ enum SystemCode : std::uint8_t {
   // Signals that all records for interval-based schemas have been published for the
   // given timestamp.
   EndOfInterval = 4,
+  // No system code was specified or this record was upgraded from a version 1 struct
+  // where the code field didn't exist.
   Unset = 255,
 };
 }  // namespace system_code

src/enums.cpp

@@ -776,6 +776,9 @@ const char* ToString(ErrorCode error_code) {
     case ErrorCode::InternalError: {
       return "internal_error";
     }
+    case ErrorCode::Unset: {
+      return "unset";
+    }
     default: {
       return "Unknown";
     }
@@ -798,6 +801,9 @@ const char* ToString(SystemCode system_code) {
     case SystemCode::EndOfInterval: {
       return "end_of_interval";
     }
+    case SystemCode::Unset: {
+      return "unset";
+    }
     default: {
       return "Unknown";
     }
@@ -1219,6 +1225,9 @@ ErrorCode FromString(const std::string& str) {
   if (str == "internal_error") {
     return ErrorCode::InternalError;
   }
+  if (str == "unset") {
+    return ErrorCode::Unset;
+  }
   throw InvalidArgumentError{"FromString<ErrorCode>", "str",
                              "unknown value '" + str + '\''};
 }
@@ -1239,6 +1248,9 @@ SystemCode FromString(const std::string& str) {
   if (str == "end_of_interval") {
     return SystemCode::EndOfInterval;
   }
+  if (str == "unset") {
+    return SystemCode::Unset;
+  }
   throw InvalidArgumentError{"FromString<SystemCode>", "str",
                              "unknown value '" + str + '\''};
 }