[gouarin]

Checklist

• The title and commit message(s) are descriptive.
• Small commits made to fix your PR have been squashed to avoid history pollution.
• Tests have been added for new features or bug fixes.
• API of new functions and classes are documented (no public API changes).

Description

Several functions are noexcept but can throw an exception xtensor raises on purpose, so the caller gets std::terminate. Most cases fail without XTENSOR_ENABLE_ASSERT:

xt::xarray<double> a = {1., 2., 3.}, b = {1., 2.};
xt::allclose(a, b);        // broadcast_error, then std::terminate
xt::filter(a, a > b);      // same
xt::norm_l1(a, {3});       // axis check, then std::terminate
(a + b).begin();           // begin() computes the broadcast shape

noexcept is removed where an exception can escape:

• shape of an xfunction: xconst_iterable/xiterable iterators, allclose, has_shape, transpose, imag, meshgrid, filter
• library checks: in1d, norms on expressions, xgenerator::assign_to, xscalar::operator() (dimension checks)
• allocation: xkeep_slice/xdrop_slice conversions

Forwarding functions (xshared_expression iterators, xfunctor_applier_base::size/shape, xconst_accessible::dimension, the xfunction constructor) are now noexcept only when the forwarded call is. isin now moves an rvalue test container instead of copying it.

Functions whose only failure is std::bad_alloc on shape-sized buffers (iterators, steppers, view constructors) keep noexcept, following C++ Core Guidelines E.12.

The new tests terminate on master and pass with the fix.

[codspeed]

Merging this PR will regress 1 benchmark

1 warning

⚠️ Unable to measure the execution of 1 benchmark

This benchmark measured no execution time, so its result is not comparable and counts as unchanged. This usually happens when the compiler removes the code under test.

Prevent compiler optimizations

See affected benchmarks

⚡ 1 improved benchmark
❌ 1 regressed benchmark
✅ 253 untouched benchmarks

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	xshape_initializer[std\:\:array<std\:\:size_t, 4>]	151.7 ns	180.8 ns	-16.13%
⚡	xshape_access[std\:\:array<std\:\:size_t, 4>]	154.4 ns	125.3 ns	+23.28%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing gouarin:fix-noexcept-throw (9b42019) with master (57f3d07)}