Implement Settings Aliases without nested calls (fixes clang 20 build)

The problem in the current implementation is that it does the following:

    struct DefineAliases
    {
        DefineAliases & setName(std::string_view value);
        DefineAliases & addAlias(std::string_view value);
    };
    DefineAlises()
      .setName()
      .addAlias()

And even though it looks very **natural and clean**, there is a problem
with such approach.

Right now ClickHouse has 1252 settings, so it will have 1252 nested
setName() calls and bunch of addAlias() calls (for those settings which
has aliases)

And this bails out on clang 20 on arm64 (likely only there because the
each frame is heavier due to larger number of registers):

    /ch/src/Core/Settings.cpp:6713:1: error: stack nearly exhausted; compilation time may suffer, and crashes due to stack overflow are likely [-Werror,-Wstack-exhausted]
     6713 | DECLARE_SETTINGS_TRAITS_ALLOW_CUSTOM_SETTINGS(SettingsTraits, LIST_OF_SETTINGS)
          | ^
    /ch/src/Core/BaseSettings.h:885:5: note: expanded from macro 'DECLARE_SETTINGS_TRAITS_ALLOW_CUSTOM_SETTINGS'
      885 |     DECLARE_SETTINGS_TRAITS_COMMON(SETTINGS_TRAITS_NAME, LIST_OF_SETTINGS_MACRO, 1)
          |     ^
    /ch/src/Core/BaseSettings.h:946:52: note: expanded from macro 'DECLARE_SETTINGS_TRAITS_COMMON'
      946 |             DefineAliases() LIST_OF_SETTINGS_MACRO(ALIAS_TO, ALIAS_FROM); \

So instead of this we can simply create the std::unordered_map for
aliases using initializer list, but, for this I have to change the
declaration, since with the chain of DECLARE() ALIAS() it is not
possible to do, so now there is DECLARE() and DECLARE_WITH_ALIAS(), the
later should be called instead if the setting has alias.

This will also to skip settings without aliases during
aliases_to_settings initialization, which should be a good thing.

P.S. Thanks to Rual new settings encapsulated so good that this changes
did not require recompile everything!

Author: azat

src/Coordination/CoordinationSettings.cpp

@@ -102,12 +102,12 @@ void CoordinationSettingsImpl::loadFromConfig(const String & config_elem, const
         max_requests_append_size = max_requests_batch_size;
 }
 
-#define INITIALIZE_SETTING_EXTERN(TYPE, NAME, DEFAULT, DESCRIPTION, FLAGS) \
+#define INITIALIZE_SETTING_EXTERN(TYPE, NAME, DEFAULT, DESCRIPTION, FLAGS, ...) \
     CoordinationSettings##TYPE NAME = &CoordinationSettingsImpl ::NAME;
 
 namespace CoordinationSetting
 {
-LIST_OF_COORDINATION_SETTINGS(INITIALIZE_SETTING_EXTERN, SKIP_ALIAS)
+LIST_OF_COORDINATION_SETTINGS(INITIALIZE_SETTING_EXTERN, INITIALIZE_SETTING_EXTERN)
 }
 
 #undef INITIALIZE_SETTING_EXTERN

src/Core/BaseSettings.h

@@ -75,10 +75,11 @@ struct BaseSettingsHelpers
   * #include <Core/BaseSettings.h>
   * #include <Core/BaseSettingsFwdMacrosImpl.h>
   *
-  * #define APPLY_FOR_MYSETTINGS(DECLARE, ALIAS) \
+  * #define APPLY_FOR_MYSETTINGS(DECLARE, DECLARE_WITH_ALIAS) \
   *     DECLARE(UInt64, a, 100, "Description of a", 0) \
   *     DECLARE(Float, f, 3.11, "Description of f", IMPORTANT) // IMPORTANT - means the setting can't be ignored by older versions) \
   *     DECLARE(String, s, "default", "Description of s", 0)
+  *     DECLARE_WITH_ALIAS(String, experimental, "default", "Description of s", 0, stable)
   *
   * DECLARE_SETTINGS_TRAITS(MySettingsTraits, APPLY_FOR_MYSETTINGS)
   * IMPLEMENT_SETTINGS_TRAITS(MySettingsTraits, APPLY_FOR_MYSETTINGS)
@@ -91,7 +92,7 @@ struct BaseSettingsHelpers
   *
   * namespace MySetting
   * {
-  * APPLY_FOR_MYSETTINGS(INITIALIZE_SETTING_EXTERN, SKIP_ALIAS)
+  * APPLY_FOR_MYSETTINGS(INITIALIZE_SETTING_EXTERN, SETTING_SKIP_TRAIT)
   * }
   * #undef INITIALIZE_SETTING_EXTERN
   *
@@ -890,7 +891,7 @@ using AliasMap = std::unordered_map<std::string_view, std::string_view>;
     { \
         struct Data \
         { \
-            LIST_OF_SETTINGS_MACRO(DECLARE_SETTINGS_TRAITS_, SKIP_ALIAS) \
+            LIST_OF_SETTINGS_MACRO(DECLARE_SETTINGS_TRAITS_, DECLARE_SETTINGS_TRAITS_) \
         }; \
         \
         class Accessor \
@@ -942,9 +943,9 @@ using AliasMap = std::unordered_map<std::string_view, std::string_view>;
         }; \
         static constexpr bool allow_custom_settings = ALLOW_CUSTOM_SETTINGS; \
         \
-        static inline const AliasMap aliases_to_settings = \
-            DefineAliases() LIST_OF_SETTINGS_MACRO(ALIAS_TO, ALIAS_FROM); \
-        \
+        static inline const AliasMap aliases_to_settings = { \
+            LIST_OF_SETTINGS_MACRO(SETTING_SKIP_TRAIT, DECLARE_SETTINGS_WITH_ALIAS_TRAITS_) \
+        }; \
         using SettingsToAliasesMap = std::unordered_map<std::string_view, std::vector<std::string_view>>; \
         static inline const SettingsToAliasesMap & settingsToAliases() \
         { \
@@ -968,36 +969,14 @@ using AliasMap = std::unordered_map<std::string_view, std::string_view>;
 
 
 /// NOLINTNEXTLINE
-#define SKIP_ALIAS(ALIAS_NAME)
-/// NOLINTNEXTLINE
-#define ALIAS_TO(TYPE, NAME, DEFAULT, DESCRIPTION, FLAGS) .setName(#NAME)
-/// NOLINTNEXTLINE
-#define ALIAS_FROM(ALIAS) .addAlias(#ALIAS)
-
-struct DefineAliases
-{
-    std::string_view name;
-    AliasMap map;
-
-    DefineAliases & setName(std::string_view value)
-    {
-        name = value;
-        return *this;
-    }
-
-    DefineAliases & addAlias(std::string_view value)
-    {
-        map.emplace(value, name);
-        return *this;
-    }
-
-    /// NOLINTNEXTLINE(google-explicit-constructor)
-    operator AliasMap() { return std::move(map); }
-};
+#define SETTING_SKIP_TRAIT(...)
 
 /// NOLINTNEXTLINE
-#define DECLARE_SETTINGS_TRAITS_(TYPE, NAME, DEFAULT, DESCRIPTION, FLAGS) \
+#define DECLARE_SETTINGS_TRAITS_(TYPE, NAME, DEFAULT, DESCRIPTION, FLAGS, ...) \
     SettingField##TYPE NAME {DEFAULT};
+/// NOLINTNEXTLINE
+#define DECLARE_SETTINGS_WITH_ALIAS_TRAITS_(TYPE, NAME, DEFAULT, DESCRIPTION, FLAGS, ALIAS) \
+    { #ALIAS, #NAME },
 
 /// NOLINTNEXTLINE
 #define IMPLEMENT_SETTINGS_TRAITS(SETTINGS_TRAITS_NAME, LIST_OF_SETTINGS_MACRO) \
@@ -1008,7 +987,7 @@ struct DefineAliases
             Accessor res; \
             constexpr int IMPORTANT = 0x01; \
             UNUSED(IMPORTANT); \
-            LIST_OF_SETTINGS_MACRO(IMPLEMENT_SETTINGS_TRAITS_, SKIP_ALIAS) \
+            LIST_OF_SETTINGS_MACRO(IMPLEMENT_SETTINGS_TRAITS_, IMPLEMENT_SETTINGS_TRAITS_) \
             for (size_t i = 0; i < res.field_infos.size(); i++) \
             { \
                 const auto & info = res.field_infos[i]; \
@@ -1032,7 +1011,7 @@ struct DefineAliases
     template class BaseSettings<SETTINGS_TRAITS_NAME>;
 
 /// NOLINTNEXTLINE
-#define IMPLEMENT_SETTINGS_TRAITS_(TYPE, NAME, DEFAULT, DESCRIPTION, FLAGS) \
+#define IMPLEMENT_SETTINGS_TRAITS_(TYPE, NAME, DEFAULT, DESCRIPTION, FLAGS, ...) \
     res.field_infos.emplace_back( \
         FieldInfo{#NAME, #TYPE, DESCRIPTION, \
             static_cast<UInt64>(FLAGS), \

src/Core/ServerSettings.cpp

@@ -1112,11 +1112,11 @@ void ServerSettingsImpl::loadSettingsFromConfig(const Poco::Util::AbstractConfig
 }
 
 
-#define INITIALIZE_SETTING_EXTERN(TYPE, NAME, DEFAULT, DESCRIPTION, FLAGS) ServerSettings##TYPE NAME = &ServerSettingsImpl ::NAME;
+#define INITIALIZE_SETTING_EXTERN(TYPE, NAME, DEFAULT, DESCRIPTION, FLAGS, ...) ServerSettings##TYPE NAME = &ServerSettingsImpl ::NAME;
 
 namespace ServerSetting
 {
-LIST_OF_SERVER_SETTINGS(INITIALIZE_SETTING_EXTERN, SKIP_ALIAS)
+LIST_OF_SERVER_SETTINGS(INITIALIZE_SETTING_EXTERN, INITIALIZE_SETTING_EXTERN)
 }
 
 #undef INITIALIZE_SETTING_EXTERN