Should `-DNDEBUG` be added to all builds?

[norbertwenzel]

I was testing a small function which contained some assert()s. (Just copied these with the original code.) I was surprised to find the assertion related code in the assembly output. I was always assuming this is removed using -DNDEBUG.

I simply added a failing assertion to the default code:

#include <cassert>

static void StringCreation(benchmark::State& state) {
  // Code inside this loop is measured repeatedly
  for (auto _ : state) {
    std::string created_string("hello");
    assert(created_string.empty());
    // Make sure the variable is not optimized away by compiler
    benchmark::DoNotOptimize(created_string);
  }
}
// Register the function as a benchmark
BENCHMARK(StringCreation);

The run fails (using the default settings, ie. -O3) with the following log:

Error or timeout
{
  "context": {
    "date": "2021-12-07 17:04:21",
    "host_name": "6f36063a71a3",
    "executable": "./bench",
    "num_cpus": 1,
    "mhz_per_cpu": 2400,
    "cpu_scaling_enabled": false,
    "caches": [
      {
        "type": "Data",
        "level": 1,
        "size": 32768,
        "num_sharing": 1
      },
      {
        "type": "Instruction",
        "level": 1,
        "size": 32768,
        "num_sharing": 1
      },
      {
        "type": "Unified",
        "level": 2,
        "size": 262144,
        "num_sharing": 1
      },
      {
        "type": "Unified",
        "level": 3,
        "size": 31457280,
        "num_sharing": 1
      }
    ],
    "load_avg": [0.51,0.54,0.5],
    "library_build_type": "release"
  },
  "benchmarks": [
bench: bench-file.cpp:8: void StringCreation(benchmark::State &): Assertion `created_string.empty()' failed.
Aborted
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.007 MB perf.data (12 samples) ]

So clearly, the assertion is run.

Is that intentional or an oversight? Should -DNDEBUG be added to all builds unconditionally, should this be an additional option to turn on/off or is this the expected behavior?