Add a custom Catch2 streaming reporter that prints one line per test
case as it starts and ends, with immediate flushing to keep CI logs
current. This makes it easy to see where the embedded/interpreter
tests are spending time and to pinpoint which test case is stuck
when builds hang (e.g., free-threading issues).
The reporter:
- Prints "[ RUN ]" when each test starts
- Prints "[ OK ]" or "[ FAILED ]" when each test ends
- Prints the Python version once at the start via Py_GetVersion()
- Uses StreamingReporterBase for immediate output (not buffered)
- Is set as the default reporter via CATCH_CONFIG_DEFAULT_REPORTER
This approach gives visibility into all tests without changing their
behavior, turning otherwise opaque 90-minute CI timeouts into
locatable issues in the Catch output.
* Avoid heap allocation for function calls with a small number of arguments
We don't have access to llvm::SmallVector or similar, but given the
limited subset of the `std::vector` API that
`function_call::args{,_convert}` need and the "reserve-then-fill"
usage pattern, it is relatively straightforward to implement custom
containers that get the job done.
Seems to improves time to call the collatz function in
pybind/pybind11_benchmark significantly; numbers are a little noisy
but there's a clear improvement from "about 60 ns per call" to "about
45 ns per call" on my machine (M4 Max Mac), as measured with
`timeit.repeat('collatz(4)', 'from pybind11_benchmark import
collatz')`.
* clang-tidy
* more clang-tidy
* clang-tidy NOLINTBEGIN/END instead of NOLINTNEXTLINE
* forgot to increase inline size after removing std::variant
* constexpr arg_vector_small_size, use move instead of swap to hopefully clarify second_pass_convert
* rename test_embed to test_low_level
* rename test_low_level to test_with_catch
* Be careful to NOINLINE slow paths
* rename array/vector members to iarray/hvector. Move comment per request. Add static_asserts for our untagged union implementation per request.
* drop is_standard_layout assertions; see https://github.com/pybind/pybind11/pull/5824#issuecomment-3308616072
