pybind11/tests/test_exc_namespace_visibility.py

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# This is not really a unit test, but probing environment/toolchain/platform-specific
# behavior under the exact same conditions as normal tests.
# The results are useful to understanding the effects of, e.g., removing
# `-fvisibility=hidden` or `__attribute__((visibility("hidden")))`, or linking
# extensions statically with the core Python interpreter.
# NOTE
# ====
# The "exc_" in "test_exc_namespace_visibility.py" is a workaround, to avoid a
# test_cross_module_exception_translator (test_exceptions.py) failure. This
# test has to be imported (by pytest) before test_exceptions.py; pytest sorts
# lexically. See https://github.com/pybind/pybind11/pull/4054 for more information.
import itertools
import namespace_visibility_1
import namespace_visibility_2
import pytest
# Please take a quick look at namespace_visibility.h first, to see what is being probed.
#
# EXPECTED is for -fvisibility=hidden or equivalent, as recommended in the docs.
EXPECTED_ALL_UNIQUE_POINTERS_OBSERVED = "AAC:AAc:AaC:Aac:aAC:aAc:aaC:aac"
# ^^^
# namespace_visibility_1 pointer|||
# namespace_visibility_1.submodule pointer|| (identical letters means same pointer)
# namespace_visibility_2 pointer|
# Upper-case: namespace visibility unspecified
# Lower-case: namespace visibility hidden
# This test probes all 2**3 combinations of u/h ** number-of-sub/modules.
#
# Also observed:
# AAA:AAc:AaC:Aac:aAC:aAc:aaC:aac -fvisibility=default Linux
# AAA:AAc:AaA:Aac:aAC:aAc:aaC:aac -fvisibility=default macOS
# AAA:AAa:AaA:Aaa:aAA:aAa:aaA:aaa everything linked statically
def test_namespace_visibility():
modules = (
namespace_visibility_1,
namespace_visibility_1.submodule,
namespace_visibility_2,
)
unique_pointer_labels = "ABC"
unique_pointers_observed = []
# u = visibility unspecified
# h = visibility hidden
for visibility in itertools.product(*([("u", "h")] * len(modules))):
# See functions in namespace_visibility_*.cpp
func = "ns_vis_" + "".join(visibility) + "_func"
ptrs = []
uq_ptrs_obs = ""
for vis, m in zip(visibility, modules):
ptr = getattr(m, func)()
ptrs.append(ptr)
lbl = unique_pointer_labels[ptrs.index(ptr)]
if vis == "h":
# Encode u/h info as upper/lower case to make the final result
# as compact as possible.
lbl = lbl.lower()
uq_ptrs_obs += lbl
unique_pointers_observed.append(uq_ptrs_obs)
all_unique_pointers_observed = ":".join(unique_pointers_observed)
if all_unique_pointers_observed != EXPECTED_ALL_UNIQUE_POINTERS_OBSERVED:
pytest.skip(
f"UNUSUAL all_unique_pointers_observed: {all_unique_pointers_observed}"
)