From bd71e0b794407869d00f4973571d3f6c4a48d137 Mon Sep 17 00:00:00 2001
From: Kefu Chai <kefu.chai@scylladb.com>
Date: Tue, 30 Jan 2024 17:12:41 +0800
Subject: [PATCH] tracing: add formatter for tracing::span_id

before this change, we rely on the default-generated fmt::formatter
created from operator<<, but fmt v10 dropped the default-generated
formatter.

in this change, we define formatters for `tracing::span_id`, and drop
its operator<<.

Refs #13245

Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>

Closes scylladb/scylladb#17058
---
 tracing/tracing.cc | 4 ----
 tracing/tracing.hh | 9 +++++++--
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/tracing/tracing.cc b/tracing/tracing.cc
index 2f74738643..deddaa0365 100644
--- a/tracing/tracing.cc
+++ b/tracing/tracing.cc
@@ -195,8 +195,4 @@ one_session_records::one_session_records(trace_type type, std::chrono::seconds s
 {
 }
 
-std::ostream& operator<<(std::ostream& os, const span_id& id) {
-    return os << id.get_id();
 }
-}
-
diff --git a/tracing/tracing.hh b/tracing/tracing.hh
index 7af98ba229..0c4b7f35ab 100644
--- a/tracing/tracing.hh
+++ b/tracing/tracing.hh
@@ -90,8 +90,6 @@ public:
     static span_id make_span_id();
 };
 
-std::ostream& operator<<(std::ostream& os, const span_id& id);
-
 // !!!!IMPORTANT!!!!
 //
 // The enum_set based on this enum is serialized using IDL, therefore new items
@@ -661,3 +659,10 @@ inline span_id span_id::make_span_id() {
     return 1 + (tracing::get_local_tracing_instance().get_next_rand_uint64() << 1);
 }
 }
+
+template <> struct fmt::formatter<tracing::span_id> {
+    constexpr auto parse(format_parse_context& ctx) { return ctx.begin(); }
+    auto format(const tracing::span_id& id, fmt::format_context& ctx) const {
+        return fmt::format_to(ctx.out(), "{}", id.get_id());
+    }
+};