From 2835da3d8ca8ffe75efd4c7796ed2bab97ee3624 Mon Sep 17 00:00:00 2001
From: Calle Wilund <calle@cloudius-systems.com>
Date: Mon, 4 May 2015 13:55:59 +0200
Subject: [PATCH] config: make sure aliases actually work properly

The nature of how boost::program_options are applied made
alias definitions clash and overwrite each other.
Make aliases not have default, and overrride bpo handling
of defaults so that they are not applied to the config object
(only used in pretty-print)

Signed-off-by: Calle Wilund <calle@cloudius-systems.com>
---
 db/config.cc | 53 +++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 44 insertions(+), 9 deletions(-)

diff --git a/db/config.cc b/db/config.cc
index 7970e62c6b..0f1a818ca3 100644
--- a/db/config.cc
+++ b/db/config.cc
@@ -132,26 +132,61 @@ bpo::options_description db::config::get_options_description() {
     return std::move(opts);
 }
 
+/*
+ * Our own bpo::typed_valye.
+ * Only difference is that we _don't_ apply defaults (they are already applied)
+ * Needed to make aliases work properly.
+ */
+template<class T, class charT = char>
+class typed_value_ex : public bpo::typed_value<T, charT> {
+public:
+    typedef bpo::typed_value<T, charT> _Super;
+
+    typed_value_ex(T* store_to)
+        : _Super(store_to)
+    {}
+    bool apply_default(boost::any& value_store) const override {
+        return false;
+    }
+};
+
+template<class T>
+inline typed_value_ex<T>* value_ex(T* v) {
+    typed_value_ex<T>* r = new typed_value_ex<T>(v);
+    return r;
+}
+
 bpo::options_description_easy_init& db::config::add_options(bpo::options_description_easy_init& init) {
-    auto opt_add = [&init](const char* name, const auto& dflt, auto& dst, const char* desc) mutable {
-        sstring tmp(name);
-        std::replace(tmp.begin(), tmp.end(), '_', '-');
+    auto opt_add =
+            [&init](const char* name, const auto& dflt, auto& dst, const char* desc) mutable {
+                sstring tmp(name);
+                std::replace(tmp.begin(), tmp.end(), '_', '-');
                 init(tmp.c_str(),
-                        bpo::value(&dst._value)->default_value(dflt)->notifier([dst](auto) mutable {
+                        value_ex(&dst._value)->default_value(dflt)->notifier([dst](auto) mutable {
                                     dst._source = config_source::CommandLine;
                                 })
-                , desc);
-    };
+                        , desc);
+            };
 
     // Add all used opts as command line opts
 #define _add_boost_opt(name, type, deflt, status, desc, ...)      \
         do_value_opt<type, value_status::status>()(opt_add, #name, type( deflt ), name, desc);
     _make_config_values(_add_boost_opt)
 
+    auto alias_add =
+            [&init](const char* name, auto& dst, const char* desc) mutable {
+                init(name,
+                        value_ex(&dst._value)->notifier([dst](auto) mutable {
+                                    dst._source = config_source::CommandLine;
+                                })
+                        , desc);
+            };
+
+
     // Handle "old" syntax with "aliases"
-    opt_add("datadir", "", data_file_directories, "alias for 'data-file-directories'");
-    opt_add("thrift-port", 0, rpc_port, "alias for 'rpc-port'");
-    opt_add("cql-port", 0, native_transport_port, "alias for 'native-transport-port'");
+    alias_add("datadir", data_file_directories, "alias for 'data-file-directories'");
+    alias_add("thrift-port", rpc_port, "alias for 'rpc-port'");
+    alias_add("cql-port", native_transport_port, "alias for 'native-transport-port'");
 
     return init;
 }