Core/Misc: Move fmt::formatter forward declaration to a common header to reduce number of replacements needed when upgrading fmt to new major version

src/common/Utilities/StringFormat.h

@@ -19,6 +19,7 @@
 #define TRINITYCORE_STRING_FORMAT_H
 
 #include "Optional.h"
+#include "StringFormatFwd.h"
 #include <fmt/core.h>
 
 namespace Trinity

src/common/Utilities/StringFormatFwd.h

@@ -0,0 +1,51 @@
+/*
+ * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TRINITYCORE_STRING_FORMAT_FWD_H
+#define TRINITYCORE_STRING_FORMAT_FWD_H
+
+#include <stdexcept>
+
+namespace fmt
+{
+inline namespace v10
+{
+template <typename T, typename Char, typename Enable>
+struct formatter;
+}
+}
+
+namespace Trinity
+{
+struct NoArgFormatterBase
+{
+    template <typename ParseContext>
+    constexpr typename ParseContext::iterator parse(ParseContext& ctx)
+    {
+        auto begin = ctx.begin(), end = ctx.end();
+        if (begin == end)
+            return begin;
+
+        if (*begin != '}')
+            throw std::invalid_argument("invalid type specifier");
+
+        return begin;
+    }
+};
+}
+
+#endif // TRINITYCORE_STRING_FORMAT_FWD_H

src/server/game/Entities/Object/ObjectGuid.h

@@ -20,13 +20,13 @@
 
 #include "Define.h"
 #include "EnumFlag.h"
+#include "StringFormatFwd.h"
 #include "advstd.h"
 #include <array>
 #include <functional>
 #include <list>
 #include <set>
 #include <span>
-#include <stdexcept>
 #include <string>
 #include <type_traits>
 #include <unordered_set>
@@ -406,34 +406,12 @@ struct std::hash<ObjectGuid>
     }
 };
 
-namespace fmt
-{
-inline namespace v10
-{
-template <typename T, typename Char, typename Enable>
-struct formatter;
-
 template <>
-struct formatter<ObjectGuid, char, void>
+struct fmt::formatter<ObjectGuid, char, void> : Trinity::NoArgFormatterBase
 {
-    template <typename ParseContext>
-    constexpr auto parse(ParseContext& ctx) -> decltype(ctx.begin())
-    {
-        auto begin = ctx.begin(), end = ctx.end();
-        if (begin == end)
-            return begin;
-
-        if (*begin != '}')
-            throw std::invalid_argument("invalid type specifier");
-
-        return begin;
-    }
-
     template <typename FormatContext>
     auto format(ObjectGuid const& guid, FormatContext& ctx) const -> decltype(ctx.out());
 };
-}
-}
 
 namespace Trinity
 {