log-format.patch

diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index aa694577d..504ae6ebd 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -207,6 +207,16 @@ std::string listLogFormats()
     return res;
 }
 
+LogFormatSetting::LogFormatSetting(Config * options,
+        LogFormat def,
+        const std::string & name,
+        const std::string & description,
+        const std::set<std::string> & aliases)
+    : BaseSetting<LogFormat>(def, name, fmt("%s Valid options are: %s.", description, listLogFormats()), aliases)
+{
+    options->addSetting(this);
+}
+
 template<> void BaseSetting<LogFormat>::set(const std::string & str)
 {
     if (str == "raw") value = LogFormat::raw;
@@ -245,7 +255,7 @@ template<> void BaseSetting<LogFormat>::convertToArg(Args & args, const std::str
 
 void setLogFormat(const LogFormat & logFormat)
 {
-    settings.logFormat = logFormat;
+    settings.logFormat.assign(logFormat);
     createDefaultLogger();
 }
 
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index 50bc496b0..cfae2c0a4 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -13,10 +13,17 @@
 
 namespace nix {
 
-std::string listLogFormats();
-
 typedef enum { smEnabled, smRelaxed, smDisabled } SandboxMode;
 
+struct LogFormatSetting : public BaseSetting<LogFormat>
+{
+    LogFormatSetting(Config * options,
+        LogFormat def,
+        const std::string & name,
+        const std::string & description,
+        const std::set<std::string> & aliases = {});
+};
+
 struct MaxBuildJobsSetting : public BaseSetting<unsigned int>
 {
     MaxBuildJobsSetting(Config * options,
@@ -887,8 +894,7 @@ public:
 
     // FIXME: default shows as "3", but should show as "bar", due to the default
     // being an enum variant
-    Setting<LogFormat> logFormat{this, LogFormat::bar, "log-format",
-        fmt("Default build output logging format. Valid options are: %s.", listLogFormats())};
+    LogFormatSetting logFormat{this, LogFormat::bar, "log-format", "Default build output logging format"};
 
     Logger* makeDefaultLogger();
 };