From 3ea7fb18d6486a70d5868702223b52990bd35426 Mon Sep 17 00:00:00 2001
From: gabime <gmelman1@gmail.com>
Date: Tue, 3 Sep 2019 14:54:17 +0300
Subject: [PATCH] Fix potential race condidion when in logger copy ctor

Don't copy other.trace - just create a new one with same size instead
---
 include/spdlog/details/backtracer.h | 13 +++++++++----
 include/spdlog/logger-inl.h         |  2 +-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/include/spdlog/details/backtracer.h b/include/spdlog/details/backtracer.h
index 5724f8b7..bdf9e9ee 100644
--- a/include/spdlog/details/backtracer.h
+++ b/include/spdlog/details/backtracer.h
@@ -17,15 +17,20 @@ namespace details {
 class backtracer
 {
     std::mutex mutex_;    
+    size_t n_messages_;
     circular_q<log_msg_buffer> messages_;
 
 public:
-    explicit backtracer(size_t n_messages) : messages_{n_messages}
+    explicit backtracer(size_t n_messages) : n_messages_{n_messages}, messages_{n_messages}
     {}
 
-    backtracer(const backtracer &other) : messages_{other.messages_}
-    {}
-  
+
+    size_t n_messages() const
+    {
+        return n_messages_;
+    }
+
+    
     void add(const log_msg &msg)
     {
         std::lock_guard<std::mutex> lock{mutex_};
diff --git a/include/spdlog/logger-inl.h b/include/spdlog/logger-inl.h
index eae23b99..78ca392d 100644
--- a/include/spdlog/logger-inl.h
+++ b/include/spdlog/logger-inl.h
@@ -25,7 +25,7 @@ SPDLOG_INLINE logger::logger(const logger &other)
 {
     if (other.tracer_)
     {
-        tracer_ = std::make_shared<details::backtracer>(*other.tracer_);
+        tracer_ = std::make_shared<details::backtracer>(other.tracer_->n_messages());
     }
 }