[Log] Handle errors during log message formatting

Author: Warrows

src/util.h

@@ -71,6 +71,9 @@ int LogPrintStr(const std::string& str);
 
 #define LogPrintf(...) LogPrint(NULL, __VA_ARGS__)
 
+/** Get format string from VA_ARGS for error reporting */
+template<typename... Args> std::string FormatStringFromLogArgs(const char *fmt, const Args&... args) { return fmt; }
+
 /**
  * When we switch to C++11, this can be switched to variadic templates instead
  * of this macro-based construction (see tinyformat.h).
@@ -81,13 +84,25 @@ int LogPrintStr(const std::string& str);
     static inline int LogPrint(const char* category, const char* format, TINYFORMAT_VARARGS(n)) \
     {                                                                                           \
         if (!LogAcceptCategory(category)) return 0;                                             \
-        return LogPrintStr(tfm::format(format, TINYFORMAT_PASSARGS(n)));                        \
+        std::string _log_msg_; /* Unlikely name to avoid shadowing variables */                 \
+        try {                                                                                   \
+            _log_msg_ = tfm::format(format, TINYFORMAT_PASSARGS(n));                            \
+        } catch (std::runtime_error &e) {                                                       \
+            _log_msg_ = "Error \"" + std::string(e.what()) + "\" while formatting log message: " + FormatStringFromLogArgs(format, TINYFORMAT_PASSARGS(n));\
+        }                                                                                       \
+        return LogPrintStr(_log_msg_);                                                          \
     }                                                                                           \
     /**   Log error and return false */                                                         \
     template <TINYFORMAT_ARGTYPES(n)>                                                           \
     static inline bool error(const char* format, TINYFORMAT_VARARGS(n))                         \
     {                                                                                           \
-        LogPrintStr(std::string("ERROR: ") + tfm::format(format, TINYFORMAT_PASSARGS(n)) + "\n");            \
+        std::string _log_msg_; /* Unlikely name to avoid shadowing variables */                 \
+        try {                                                                                   \
+            _log_msg_ = tfm::format(format, TINYFORMAT_PASSARGS(n));                            \
+        } catch (std::runtime_error &e) {                                                       \
+            _log_msg_ = "Error \"" + std::string(e.what()) + "\" while formatting log message: " + FormatStringFromLogArgs(format, TINYFORMAT_PASSARGS(n));\
+        }                                                                                       \
+        LogPrintStr(std::string("ERROR: ") + _log_msg_ + "\n");                                 \
         return false;                                                                           \
     }