Support --no-net for backwards compatibility

src/libutil/args.cc

@@ -14,6 +14,8 @@ void Args::addFlag(Flag && flag_)
         assert(flag->handler.arity == flag->labels.size());
     assert(flag->longName != "");
     longFlags[flag->longName] = flag;
+    for (auto & alias : flag->aliases)
+        longFlags[alias] = flag;
     if (flag->shortName) shortFlags[flag->shortName] = flag;
 }
 
@@ -191,6 +193,7 @@ nlohmann::json Args::toJSON()
 
     for (auto & [name, flag] : longFlags) {
         auto j = nlohmann::json::object();
+        if (flag->aliases.count(name)) continue;
         if (flag->shortName)
             j["shortName"] = std::string(1, flag->shortName);
         if (flag->description != "")

src/libutil/args.hh

@@ -97,6 +97,7 @@ protected:
         typedef std::shared_ptr<Flag> ptr;
 
         std::string longName;
+        std::set<std::string> aliases;
         char shortName = 0;
         std::string description;
         std::string category;

src/nix/main.cc

@@ -92,6 +92,7 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
 
         addFlag({
             .longName = "offline",
+            .aliases = {"no-net"}, // FIXME: remove
             .description = "Disable substituters and consider all previously downloaded files up-to-date.",
             .handler = {[&]() { useNet = false; }},
         });