Catch exceptions thrown on invalid format strings in the log backend and print an error message to signal the issue.

lib/src/srslog/formatters/json_formatter.cpp

@@ -28,7 +28,11 @@ void json_formatter::format(detail::log_entry_metadata&& metadata, fmt::memory_b
   if (metadata.fmtstring) {
     if (metadata.store) {
       fmt::basic_format_args<fmt::basic_printf_context_t<char> > args(*metadata.store);
-      fmt::vprintf(buffer, fmt::to_string_view(metadata.fmtstring), args);
+      try {
+        fmt::vprintf(buffer, fmt::to_string_view(metadata.fmtstring), args);
+      } catch (...) {
+        fmt::print(stderr, "srsLog error - Invalid format string: \"{}\"\n", metadata.fmtstring);
+      }
       fmt::format_to(buffer, fmt::to_string_view("\""));
     } else {
       fmt::format_to(buffer, "{}\"", metadata.fmtstring);
@@ -58,7 +62,11 @@ void json_formatter::format_context_begin(const detail::log_entry_metadata& md,
     if (md.store) {
       fmt::format_to(buffer, "  \"log_entry\": \"");
       fmt::basic_format_args<fmt::basic_printf_context_t<char> > args(*md.store);
-      fmt::vprintf(buffer, fmt::to_string_view(md.fmtstring), args);
+      try {
+        fmt::vprintf(buffer, fmt::to_string_view(md.fmtstring), args);
+      } catch (...) {
+        fmt::print(stderr, "srsLog error - Invalid format string: \"{}\"\n", md.fmtstring);
+      }
       fmt::format_to(buffer, "\",\n");
     } else {
       fmt::format_to(buffer, "  \"log_entry\": \"{}\",\n", md.fmtstring);

lib/src/srslog/formatters/text_formatter.cpp

@@ -66,7 +66,11 @@ void text_formatter::format(detail::log_entry_metadata&& metadata, fmt::memory_b
   if (metadata.fmtstring) {
     if (metadata.store) {
       fmt::basic_format_args<fmt::basic_printf_context_t<char> > args(*metadata.store);
-      fmt::vprintf(buffer, fmt::to_string_view(metadata.fmtstring), args);
+      try {
+        fmt::vprintf(buffer, fmt::to_string_view(metadata.fmtstring), args);
+      } catch (...) {
+        fmt::print(stderr, "srsLog error - Invalid format string: \"{}\"\n", metadata.fmtstring);
+      }
       fmt::format_to(buffer, "\n");
     } else {
       fmt::format_to(buffer, "{}\n", metadata.fmtstring);
@@ -106,7 +110,11 @@ void text_formatter::format_context_end(const detail::log_entry_metadata& md,
   if (md.store) {
     fmt::format_to(buffer, "]: ");
     fmt::basic_format_args<fmt::basic_printf_context_t<char> > args(*md.store);
-    fmt::vprintf(buffer, fmt::to_string_view(md.fmtstring), args);
+    try {
+      fmt::vprintf(buffer, fmt::to_string_view(md.fmtstring), args);
+    } catch (...) {
+      fmt::print(stderr, "srsLog error - Invalid format string: \"{}\"\n", md.fmtstring);
+    }
     fmt::format_to(buffer, "\n");
   } else {
     fmt::format_to(buffer, "]: {}\n", md.fmtstring);