* Improve C++ test infrastructure and disable hanging test
This commit improves the C++ test infrastructure to ensure test output
is visible in CI logs, and disables a test that hangs on free-threaded
Python 3.14+.
Changes:
## CI/test infrastructure improvements
- .github/workflows: Added `timeout-minutes: 3` to all C++ test steps
to prevent indefinite hangs.
- tests/**/CMakeLists.txt: Added `USES_TERMINAL` to C++ test targets
(cpptest, test_cross_module_rtti, test_pure_cpp) to ensure output is
shown immediately rather than buffered and possibly lost on crash/timeout.
- tests/test_with_catch/catch.cpp: Added a custom Catch2 progress reporter
with timestamps, Python version info, and a SIGTERM handler to make test
execution and failures clearly visible in CI logs.
## Disabled hanging test
- The "Move Subinterpreter" test is disabled on free-threaded Python 3.14+
due to a hang in Py_EndInterpreter() when the subinterpreter is destroyed
from a different thread than it was created on. Work on fixing the
underlying issue will continue under PR #5940.
Context: We were in the dark for months (since we started testing with
Python 3.14t) because CI logs gave no clue about the root cause of hangs.
This led to ignoring intermittent hangs (mostly on macOS). Our hand was
forced only with the Python 3.14.1 release, when hangs became predictable
on all platforms.
For the full development history of these changes, see PR #5933.
* Add test summary to progress reporter
Print the total number of test cases and assertions at the end of the
test run, making it easy to spot if tests are disabled or added.
Example output:
[ PASSED ] 20 test cases, 1589 assertions.
* Add PYBIND11_CATCH2_SKIP_IF macro to skip tests at runtime
Catch2 v2 doesn't have native skip support (v3 does with SKIP()).
This macro allows tests to be skipped with a visible message while
still appearing in the test list.
Use this for the Move Subinterpreter test on free-threaded Python 3.14+
so it shows as skipped rather than being conditionally compiled out.
Example output:
[ RUN ] Move Subinterpreter
[ SKIPPED ] Skipped on free-threaded Python 3.14+ (see PR #5940)
[ OK ] Move Subinterpreter
* Fix clang-tidy bugprone-macro-parentheses warning in PYBIND11_CATCH2_SKIP_IF
* 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
