Throw if rotating_file_sink constructor receives max_size==0 as arg

include/spdlog/sinks/rotating_file_sink-inl.h

@@ -31,6 +31,10 @@ SPDLOG_INLINE rotating_file_sink<Mutex>::rotating_file_sink(
     , max_files_(max_files)
     , file_helper_{event_handlers}
 {
+    if(max_size == 0)
+    {
+        throw_spdlog_ex("rotating sink constructor: max_size arg cannot be zero");
+    }
     file_helper_.open(calc_filename(base_filename_, 0));
     current_size_ = file_helper_.size(); // expensive. called only once
     if (rotate_on_open && current_size_ > 0)

tests/test_file_logging.cpp

@@ -98,3 +98,12 @@ TEST_CASE("rotating_file_logger2", "[rotating_logger]]")
     REQUIRE(get_filesize(ROTATING_LOG) <= max_size);
     REQUIRE(get_filesize(ROTATING_LOG ".1") <= max_size);
 }
+
+// test that passing max_size=0 throws
+TEST_CASE("rotating_file_logger3", "[rotating_logger]]")
+{
+    prepare_logdir();
+    size_t max_size = 0;
+    spdlog::filename_t basename = SPDLOG_FILENAME_T(ROTATING_LOG);
+    REQUIRE_THROWS_AS(spdlog::rotating_logger_mt("logger", basename, max_size, 0), spdlog::spdlog_ex);
+}