python: fix segfault on empty argv in main()

Author: senyai

bindings/python/google_benchmark/benchmark.cc

@@ -17,14 +17,13 @@ std::vector<std::string> Initialize(const std::vector<std::string>& argv) {
   // The `argv` pointers here become invalid when this function returns, but
   // benchmark holds the pointer to `argv[0]`. We create a static copy of it
   // so it persists, and replace the pointer below.
-  static std::string executable_name(argv[0]);
-  std::vector<char*> ptrs;
-  ptrs.reserve(argv.size());
-  for (auto& arg : argv) {
-    ptrs.push_back(const_cast<char*>(arg.c_str()));
+  static std::string executable_name(argv.empty() ? "unknown" : argv[0]);
+  int argc = static_cast<int>(std::max(std::size_t{1}, argv.size()));
+  std::vector<char*> ptrs(argc);
+  for (size_t i = 0; i < argv.size(); ++i) {
+    ptrs[i] = const_cast<char*>(argv[i].c_str());
   }
   ptrs[0] = const_cast<char*>(executable_name.c_str());
-  int argc = static_cast<int>(argv.size());
   benchmark::Initialize(&argc, ptrs.data());
   std::vector<std::string> remaining_argv;
   remaining_argv.reserve(argc);