Fixed format_to deprecated warning by wrapping the buffer with std::back_inserter

include/spdlog/details/fmt_helper.h

@@ -4,6 +4,7 @@
 
 #include <chrono>
 #include <type_traits>
+#include <iterator>
 #include <spdlog/fmt/fmt.h>
 #include <spdlog/common.h>
 
@@ -54,7 +55,7 @@ inline void pad2(int n, memory_buf_t &dest)
     }
     else // unlikely, but just in case, let fmt deal with it
     {
-        fmt::format_to(dest, "{:02}", n);
+        fmt::format_to(std::back_inserter(dest), "{:02}", n);
     }
 }
 

include/spdlog/logger.h

@@ -23,6 +23,8 @@
 #endif
 
 #include <vector>
+#include <iterator>
+
 #ifndef SPDLOG_NO_EXCEPTIONS
 #define SPDLOG_LOGGER_CATCH()                                                                                                              \
     catch (const std::exception &ex)                                                                                                       \
@@ -238,7 +240,7 @@ public:
         {
             // format to wmemory_buffer and convert to utf8
             fmt::wmemory_buffer wbuf;
-            fmt::format_to(wbuf, fmt, std::forward<Args>(args)...);
+            fmt::format_to(std::back_inserter(wbuf), fmt, std::forward<Args>(args)...);
 
             memory_buf_t buf;
             details::os::wstr_to_utf8buf(wstring_view_t(wbuf.data(), wbuf.size()), buf);
@@ -338,7 +340,7 @@ protected:
         SPDLOG_TRY
         {
             memory_buf_t buf;
-            fmt::format_to(buf, fmt, std::forward<Args>(args)...);
+            fmt::format_to(std::back_inserter(buf), fmt, std::forward<Args>(args)...);
             details::log_msg log_msg(loc, name_, lvl, string_view_t(buf.data(), buf.size()));
             log_it_(log_msg, log_enabled, traceback_enabled);
         }

include/spdlog/sinks/dup_filter_sink.h

@@ -63,7 +63,7 @@ protected:
         if (skip_counter_ > 0)
         {
             memory_buf_t buf;
-            fmt::format_to(buf, "Skipped {} duplicate messages..", skip_counter_);
+            fmt::format_to(std::back_inserter(buf), "Skipped {} duplicate messages..", skip_counter_);
             details::log_msg skipped_msg{msg.logger_name, level::info, string_view_t{buf.data(), buf.size()}};
             dist_sink<Mutex>::sink_it_(skipped_msg);
         }

tests/test_daily_logger.cpp

@@ -15,7 +15,7 @@ TEST_CASE("daily_logger with dateonly calculator", "[daily_logger]")
     spdlog::filename_t basename = SPDLOG_FILENAME_T("test_logs/daily_dateonly");
     std::tm tm = spdlog::details::os::localtime();
     filename_memory_buf_t w;
-    fmt::format_to(w, SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}"), basename, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
+    fmt::format_to(std::back_inserter(w), SPDLOG_FILENAME_T("{}_{:04d}-{:02d}-{:02d}"), basename, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
 
     auto logger = spdlog::create<sink_type>("logger", basename, 0, 0);
     for (int i = 0; i < 10; ++i)
@@ -40,7 +40,8 @@ struct custom_daily_file_name_calculator
     static spdlog::filename_t calc_filename(const spdlog::filename_t &basename, const tm &now_tm)
     {
         filename_memory_buf_t w;
-        fmt::format_to(w, SPDLOG_FILENAME_T("{}{:04d}{:02d}{:02d}"), basename, now_tm.tm_year + 1900, now_tm.tm_mon + 1, now_tm.tm_mday);
+        fmt::format_to(std::back_inserter(w), SPDLOG_FILENAME_T("{}{:04d}{:02d}{:02d}"), basename, now_tm.tm_year + 1900,
+            now_tm.tm_mon + 1, now_tm.tm_mday);
         return fmt::to_string(w);
     }
 };
@@ -55,7 +56,7 @@ TEST_CASE("daily_logger with custom calculator", "[daily_logger]")
     spdlog::filename_t basename = SPDLOG_FILENAME_T("test_logs/daily_dateonly");
     std::tm tm = spdlog::details::os::localtime();
     filename_memory_buf_t w;
-    fmt::format_to(w, SPDLOG_FILENAME_T("{}{:04d}{:02d}{:02d}"), basename, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
+    fmt::format_to(std::back_inserter(w), SPDLOG_FILENAME_T("{}{:04d}{:02d}{:02d}"), basename, tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
 
     auto logger = spdlog::create<sink_type>("logger", basename, 0, 0);
     for (int i = 0; i < 10; ++i)

tests/test_file_helper.cpp

@@ -10,7 +10,7 @@ using spdlog::details::file_helper;
 static void write_with_helper(file_helper &helper, size_t howmany)
 {
     spdlog::memory_buf_t formatted;
-    fmt::format_to(formatted, "{}", std::string(howmany, '1'));
+    fmt::format_to(std::back_inserter(formatted), "{}", std::string(howmany, '1'));
     helper.write(formatted);
     helper.flush();
 }

tests/test_pattern_formatter.cpp

@@ -64,7 +64,7 @@ TEST_CASE("color range test1", "[pattern_formatter]")
     auto formatter = std::make_shared<spdlog::pattern_formatter>("%^%v%$", spdlog::pattern_time_type::local, "\n");
 
     memory_buf_t buf;
-    fmt::format_to(buf, "Hello");
+    fmt::format_to(std::back_inserter(buf), "Hello");
     memory_buf_t formatted;
     std::string logger_name = "test";
     spdlog::details::log_msg msg(logger_name, spdlog::level::info, spdlog::string_view_t(buf.data(), buf.size()));