debug: Fix crash handling null strings

rustyconover · rustyconover · commit 218aead649d9 · 2020-01-26T10:53:26.000-05:00
When internal debug is enabled output null strings as
"(null)" rather than crashing matching glibc's behavior.
diff --git a/src/debug_utils-inl.h b/src/debug_utils-inl.h
@@ -21,7 +21,9 @@ struct ToStringHelper {
                 enable_if<std::is_arithmetic<T>::value, bool>::type,
             typename dummy = bool>
   static std::string Convert(const T& value) { return std::to_string(value); }
-  static std::string Convert(const char* value) { return value; }
+  static std::string Convert(const char* value) {
+    return value ? value : "(null)";
+  }
   static std::string Convert(const std::string& value) { return value; }
   static std::string Convert(bool value) { return value ? "true" : "false"; }
 };
