crimson/common: replace deprecated fmt::localtime() with localtime_r()

Replace fmt::localtime() with localtime_r() to fix build failure with
fmt 11.2.0. The fmt::localtime() function was deprecated in favor of
std::localtime, causing build errors when treating warnings as errors:

```
[1/2] Building CXX object src/crimson/CMakeFiles/crimson-common.dir/common/formatter.cc.o
/home/kefu/dev/ceph/src/crimson/common/formatter.cc: In member function ‘auto fmt::v11::formatter<std::chrono::time_point<seastar::lowres_system_clock, std::chrono::duration<long int, std::ratio<1, 1000000000> > > >::format(const seastar::lowres_system_clock::time_point&, FormatContext&) const’:
/home/kefu/dev/ceph/src/crimson/common/formatter.cc:28:41: warning: ‘tm fmt::v11::localtime(time_t)’ is deprecated [-Wdeprecated-declarations]
   28 |                           fmt::localtime(tt), milliseconds);
      |                           ~~~~~~~~~~~~~~^~~~
In file included from /home/kefu/dev/ceph/src/fmt/include/fmt/ostream.h:23,
                 from /home/kefu/dev/ceph/src/seastar/include/seastar/util/backtrace.hh:40,
                 from /home/kefu/dev/ceph/src/seastar/include/seastar/core/task.hh:25,
                 from /home/kefu/dev/ceph/src/seastar/include/seastar/core/future.hh:36,
                 from /home/kefu/dev/ceph/src/seastar/include/seastar/core/timer.hh:24,
                 from /home/kefu/dev/ceph/src/seastar/include/seastar/core/lowres_clock.hh:26,
                 from /home/kefu/dev/ceph/src/crimson/common/formatter.h:4,
                 from /home/kefu/dev/ceph/src/crimson/common/formatter.cc:4:
/home/kefu/dev/ceph/src/fmt/include/fmt/chrono.h:538:28: note: declared here
  538 | FMT_DEPRECATED inline auto localtime(std::time_t time) -> std::tm {
      |                            ^~~~~~~~~
```

Unlike other parts of the codebase, this implementation checks the return
value of localtime_r() to preserve the error-handling behavior of
fmt::localtime(), which throws on failure. Future changes may opt for
consistency with the broader codebase over behavioral compatibility.

Signed-off-by: Kefu Chai <tchaikov@gmail.com>

diff --git a/src/crimson/common/formatter.cc b/src/crimson/common/formatter.cc
index 9ced61d9848647b7210661e6014cb55919576777..2b59a710cf9ba21044d498d75cb3a4f56d3cb653 100644 (file)
--- a/src/crimson/common/formatter.cc
+++ b/src/crimson/common/formatter.cc
@@ -3,6 +3,7 @@
 
 #include "formatter.h"
 
+#include <chrono>
 #include <fmt/format.h>
 #if FMT_VERSION >= 60000
 #include <fmt/chrono.h>
@@ -20,12 +21,15 @@ struct fmt::formatter<seastar::lowres_system_clock::time_point> {
   template <typename FormatContext>
   auto format(const seastar::lowres_system_clock::time_point& t,
               FormatContext& ctx) const {
-    std::time_t tt = std::chrono::duration_cast<std::chrono::seconds>(
-      t.time_since_epoch()).count();
-    auto milliseconds = (t.time_since_epoch() %
-                         std::chrono::seconds(1)).count();
-    return fmt::format_to(ctx.out(), "{:%Y-%m-%d %H:%M:%S} {:03d}",
-                          fmt::localtime(tt), milliseconds);
+    auto milliseconds = std::chrono::duration_cast<std::chrono::milliseconds>(
+      t.time_since_epoch() % std::chrono::seconds(1)).count();
+
+    std::time_t time = seastar::lowres_system_clock::to_time_t(t);
+    std::tm tm_local;
+    if (!localtime_r(&time, &tm_local)) {
+      throw fmt::format_error("time_t value out of range");
+    }
+    return fmt::format_to(ctx.out(), "{:%F %T} {:03d}", tm_local, milliseconds);
   }
 };