Make '--help' do the same as 'help' (i.e. show a manpage)

5 files changed, 17 insertions, 61 deletions

diff --git a/src/nix/command.cc b/src/nix/command.cc
index ba58c7d6b..20eeefe91 100644
--- a/src/nix/command.cc
+++ b/src/nix/command.cc
@@ -27,11 +27,6 @@ nix::Commands RegisterCommand::getCommandsFor(const std::vector<std::string> & p
     return res;
 }
 
-void NixMultiCommand::printHelp(const string & programName, std::ostream & out)
-{
-    MultiCommand::printHelp(programName, out);
-}
-
 nlohmann::json NixMultiCommand::toJSON()
 {
     // FIXME: use Command::toJSON() as well.
diff --git a/src/nix/command.hh b/src/nix/command.hh
index f325cd906..791dd0f1e 100644
--- a/src/nix/command.hh
+++ b/src/nix/command.hh
@@ -25,8 +25,6 @@ static constexpr Command::Category catNixInstallation = 102;
 
 struct NixMultiCommand : virtual MultiCommand, virtual Command
 {
-    void printHelp(const string & programName, std::ostream & out) override;
-
     nlohmann::json toJSON() override;
 };
 
diff --git a/src/nix/main.cc b/src/nix/main.cc
index 80422bd24..77a13c913 100644
--- a/src/nix/main.cc
+++ b/src/nix/main.cc
@@ -54,6 +54,8 @@ static bool haveInternet()
 std::string programPath;
 char * * savedArgv;
 
+struct HelpRequested { };
+
 struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
 {
     bool printBuildLogs = false;
@@ -71,22 +73,7 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
         addFlag({
             .longName = "help",
             .description = "Show usage information.",
-            .handler = {[&]() { if (!completions) showHelpAndExit(); }},
-        });
-
-        addFlag({
-            .longName = "help-config",
-            .description = "Show configuration settings.",
-            .handler = {[&]() {
-                std::cout << "The following configuration settings are available:\n\n";
-                Table2 tbl;
-                std::map<std::string, Config::SettingInfo> settings;
-                globalConfig.getSettings(settings);
-                for (const auto & s : settings)
-                    tbl.emplace_back(s.first, s.second.description);
-                printTable(std::cout, tbl);
-                throw Exit();
-            }},
+            .handler = {[&]() { throw HelpRequested(); }},
         });
 
         addFlag({
@@ -154,33 +141,6 @@ struct NixArgs : virtual MultiCommand, virtual MixCommonArgs
         return pos;
     }
 
-    void printFlags(std::ostream & out) override
-    {
-        Args::printFlags(out);
-        std::cout <<
-            "\n"
-            "In addition, most configuration settings can be overriden using '--" ANSI_ITALIC "name value" ANSI_NORMAL "'.\n"
-            "Boolean settings can be overriden using '--" ANSI_ITALIC "name" ANSI_NORMAL "' or '--no-" ANSI_ITALIC "name" ANSI_NORMAL "'. See 'nix\n"
-            "--help-config' for a list of configuration settings.\n";
-    }
-
-    void printHelp(const string & programName, std::ostream & out) override
-    {
-        MultiCommand::printHelp(programName, out);
-
-#if 0
-        out << "\nFor full documentation, run 'man " << programName << "' or 'man " << programName << "-" ANSI_ITALIC "COMMAND" ANSI_NORMAL "'.\n";
-#endif
-
-        std::cout << "\nNote: this program is " ANSI_RED "EXPERIMENTAL" ANSI_NORMAL " and subject to change.\n";
-    }
-
-    void showHelpAndExit()
-    {
-        printHelp(programName, std::cout);
-        throw Exit();
-    }
-
     std::string description() override
     {
         return "a tool for reproducible and declarative configuration management";
@@ -298,6 +258,18 @@ void mainWrapped(int argc, char * * argv)
 
     try {
         args.parseCmdline(argvToStrings(argc, argv));
+    } catch (HelpRequested &) {
+        std::vector<std::string> subcommand;
+        MultiCommand * command = &args;
+        while (command) {
+            if (command && command->command) {
+                subcommand.push_back(command->command->first);
+                command = dynamic_cast<MultiCommand *>(&*command->command->second);
+            } else
+                break;
+        }
+        showHelp(subcommand);
+        return;
     } catch (UsageError &) {
         if (!completions) throw;
     }
@@ -306,7 +278,8 @@ void mainWrapped(int argc, char * * argv)
 
     initPlugins();
 
-    if (!args.command) args.showHelpAndExit();
+    if (!args.command)
+        throw UsageError("no subcommand specified");
 
     if (args.command->first != "repl"
         && args.command->first != "doctor"
diff --git a/src/nix/nar.cc b/src/nix/nar.cc
index 0775d3c25..dbb043d9b 100644
--- a/src/nix/nar.cc
+++ b/src/nix/nar.cc
@@ -28,11 +28,6 @@ struct CmdNar : NixMultiCommand
         command->second->prepare();
         command->second->run();
     }
-
-    void printHelp(const string & programName, std::ostream & out) override
-    {
-        MultiCommand::printHelp(programName, out);
-    }
 };
 
 static auto rCmdNar = registerCommand<CmdNar>("nar");
diff --git a/src/nix/store.cc b/src/nix/store.cc
index e91bcc503..44e53c7c7 100644
--- a/src/nix/store.cc
+++ b/src/nix/store.cc
@@ -21,11 +21,6 @@ struct CmdStore : virtual NixMultiCommand
         command->second->prepare();
         command->second->run();
     }
-
-    void printHelp(const string & programName, std::ostream & out) override
-    {
-        MultiCommand::printHelp(programName, out);
-    }
 };
 
 static auto rCmdStore = registerCommand<CmdStore>("store");