1. 09 Feb, 2022 1 commit
  2. 08 Feb, 2022 1 commit
  3. 06 Feb, 2022 1 commit
    • Michał Górny's avatar
      tests: update catch to 2.13.5 to fix glibc 2.34 failures (#3679) · 96b943be
      Michał Górny authored
      * Download catch for MinGw
      
      * Fix rest of MinGW
      
      * fix: update catch to 2.13.5 to fix glibc 2.34 failures
      
      Update the downloaded Catch version to 2.13.5, in order to fix build
      failure on glibc 2.34:
      
      ```
      In file included from /usr/include/signal.h:328,
                       from /tmp/pybind11/.nox/tests-3-9/tmp/tests/catch/catch.hpp:8030,
                       from /tmp/pybind11/tests/test_embed/catch.cpp:13:
      /tmp/pybind11/.nox/tests-3-9/tmp/tests/catch/catch.hpp:10818:58: error: call to non-‘constexpr’ function ‘long int sysconf(int)’
      10818 |     static constexpr std::size_t sigStackSize = 32768 >= MINSIGSTKSZ ? 32768 : MINSIGSTKSZ;
            |                                                          ^~~~~~~~~~~
      In file included from /usr/include/python3.9/Python.h:36,
                       from /tmp/pybind11/include/pybind11/detail/common.h:215,
                       from /tmp/pybind11/include/pybind11/pytypes.h:12,
                       from /tmp/pybind11/include/pybind11/cast.h:13,
                       from /tmp/pybind11/include/pybind11/attr.h:13,
                       from /tmp/pybind11/include/pybind11/pybind11.h:13,
                       from /tmp/pybind11/include/pybind11/embed.h:12,
                       from /tmp/pybind11/tests/test_embed/catch.cpp:4:
      /usr/include/unistd.h:640:17: note: ‘long int sysconf(int)’ declared here
        640 | extern long int sysconf (int __name) __THROW;
            |                 ^~~~~~~
      In file included from /tmp/pybind11/tests/test_embed/catch.cpp:13:
      /tmp/pybind11/.nox/tests-3-9/tmp/tests/catch/catch.hpp:10877:45: error: size of array ‘altStackMem’ is not an integral constant-expression
      10877 |     char FatalConditionHandler::altStackMem[sigStackSize] = {};
            |                                             ^~~~~~~~~~~~
      ```
      
      The newest Catch version cannot be used yet because of regression:
      https://github.com/catchorg/Catch2/pull/2364
      
      
      
      * fix: add option for _ check, only define on pybind11
      
      * Revert "fix: add option for _ check, only define on pybind11"
      
      This reverts commit 86817db488c547816e21e20d678db318bb286384.
      
      * fix: only undef _ for catch cpp creation.
      Co-authored-by: default avatarAaron Gokaslan <skylion.aaron@gmail.com>
      Co-authored-by: default avatarHenry Schreiner <henryschreineriii@gmail.com>
      96b943be
  4. 03 Feb, 2022 1 commit
  5. 31 Jan, 2022 1 commit
  6. 27 Jan, 2022 1 commit
  7. 16 Jan, 2022 1 commit
  8. 14 Jan, 2022 1 commit
    • Aaron Gokaslan's avatar
      Add support for nested C++11 exceptions (#3608) · d2ec8367
      Aaron Gokaslan authored
      * Add support for nested C++11 exceptions
      
      * Remove wrong include
      
      * Fix if directive
      
      * Fix missing skipif
      
      * Simplify code and try to work around MSVC bug
      
      * Clarify comment
      
      * Further simplify code
      
      * Remove the last extra throw statement
      
      * Qualify auto
      
      * Fix typo
      
      * Add missing return for consistency
      
      * Fix clang-tidy complaint
      
      * Fix python2 stub
      
      * Make clang-tidy happy
      
      * Fix compile error
      
      * Fix python2 function signature
      
      * Extract C++20 utility and backport
      
      * Cleanup code a bit more
      
      * Improve test case
      
      * Consolidate code and fix signature
      
      * Fix typo
      d2ec8367
  9. 12 Jan, 2022 2 commits
  10. 11 Jan, 2022 2 commits
  11. 29 Dec, 2021 1 commit
    • Ralf W. Grosse-Kunstleve's avatar
      Adding dedicated test_const_name. (#3578) · 1bbaeb34
      Ralf W. Grosse-Kunstleve authored
      * Adding dedicated test_const_name.
      
      Also exercises pybind11::detail::_ backward compatibility.
      
      See also: PR #3423
      
      * Backing out tests involving int_to_str (requires C++17 or higher).
      
      * Suppressing clang-tidy errors.
      
      * Disabling test_const_name for MSVC 2015 due to bizarre failures.
      
      * Stacking @pytest.mark.parametrize (thanks to @skylion007 for pointing out).
      1bbaeb34
  12. 21 Dec, 2021 1 commit
  13. 03 Dec, 2021 1 commit
    • Jason Rhinelander's avatar
      Expand std::string_view support to str, bytes, memoryview (#3521) · b4939fcb
      Jason Rhinelander authored
      * Expand string_view support to str, bytes, memoryview
      
      1. Allows constructing a str or bytes implicitly from a string_view;
         this is essentially a small shortcut allowing a caller to write
         `py::bytes{sv}` rather than `py::bytes{sv.data(), sv.size()}`.
      
      2. Allows implicit conversion *to* string_view from py::bytes -- this
         saves a fair bit more as currently there is no simple way to get such
         a view of the bytes without copying it (or resorting to Python API
         calls).
      
         (This is not done for `str` because when the str contains unicode we
         have to allocate to a temporary and so there might not be some string
         data we can properly view without owning.)
      
      3. Allows `memoryview::from_memory` to accept a string_view.  As with
         the other from_memory calls, it's entirely your responsibility to
         keep it alive.
      
      This also required moving the string_view availability detection into
      detail/common.h because this PR needs it in pytypes.h, which is higher
      up the include chain than cast.h where it was being detected currently.
      
      * Move string_view include to pytypes.h
      
      * CI-testing a fix for the "ambiguous conversion" issue.
      
      This change is known to fix the `tensorflow::tstring` issue reported under https://github.com/pybind/pybind11/pull/3521#issuecomment-985100965
      
      
      
      TODO: Minimal reproducer for the `tensorflow::tstring` issue.
      
      * Make clang-tidy happy (hopefully).
      
      * Adding minimal reproducer for the `tensorflow::tstring` issue.
      
      Error without the enable_if trick:
      
      ```
      /usr/local/google/home/rwgk/forked/pybind11/tests/test_builtin_casters.cpp:169:16: error: ambiguous conversion for functional-style cast from 'TypeWithBothOperatorStringAndStringView' to 'py::bytes'
              return py::bytes(TypeWithBothOperatorStringAndStringView());
                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      /usr/local/google/home/rwgk/forked/pybind11/include/pybind11/detail/../pytypes.h:1174:5: note: candidate constructor
          bytes(const std::string &s) : bytes(s.data(), s.size()) { }
          ^
      /usr/local/google/home/rwgk/forked/pybind11/include/pybind11/detail/../pytypes.h:1191:5: note: candidate constructor
          bytes(std::string_view s) : bytes(s.data(), s.size()) { }
          ^
      ```
      
      * Adding missing NOLINTNEXTLINE
      
      * Also apply ambiguous conversion workaround to str()
      Co-authored-by: default avatarRalf W. Grosse-Kunstleve <rwgk@google.com>
      b4939fcb
  14. 22 Nov, 2021 1 commit
  15. 21 Nov, 2021 1 commit
    • Jason Rhinelander's avatar
      Fix py::kw_only when used before the first arg of a method (#3488) · 673b4be3
      Jason Rhinelander authored
      * Fix py::kw_only when used before the first arg of a method
      
      The implicit space for the `self` argument isn't added until we hit the
      first argument, but this wasn't being done for kw_only or pos_only, and
      so a kw_only before the first argument would break.
      
      This fixes it by properly checking whether we need to add the self arg.
      
      (The pos_only issue here was extremely mild -- you didn't get the `/` in
      the docstring, but AFAICT it has no other effect since there are no
      meaningful arguments before it anyway).
      
      * Style changes
      
      - rename check_have_self_arg -> append_self_arg_if_needed
      
      - move the argument name inline comments before the args instead of
        after
      673b4be3
  16. 18 Nov, 2021 1 commit
  17. 17 Nov, 2021 1 commit
  18. 15 Nov, 2021 1 commit
    • Trigve's avatar
      [master] Wrong caching of overrides (#3465) · afdc09de
      Trigve authored
      * override: Fix wrong caching of the overrides
      
      There was a problem when the python type, which was stored in override
      cache for C++ functions, was destroyed and  the record wasn't removed from the
      override cache. Therefor, dangling pointer was stored there. Then when the
      memory was reused and new type was allocated at the given address and the
      method with the same name (as previously stored in the cache) was actually
      overridden in python, it would wrongly find it in the override cache for C++
      functions and therefor override from python wouldn't be called.
      The fix is to erase the type from the override cache when the type is destroyed.
      
      * test: Pass by const ref instead of by value (clang-tidy)
      
      * test: Rename classes and move to different files
      
      Rename the classes and files so they're no too generic. Also, better place to
      test the stuff is in test_virtual_functions.cpp/.py as we're basically testing
      the virtual functions/trampolines.
      
      * Add TODO for erasure code
      
      * [pre-commit.ci] auto fixes from pre-commit.com hooks
      
      for more information, see https://pre-commit.ci
      
      Co-authored-by: default avatarpre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
      afdc09de
  19. 08 Nov, 2021 1 commit
    • Antony Lee's avatar
      fix(setup =_helpers): don't add -g0 CFLAGS sets -g (#3436) · b11ff912
      Antony Lee authored
      On Unix, setuptools prepends $CFLAGS and $CPPFLAGS to the compiler flags
      (they always come before extra_compile_args and anything else; see
      distutils.sysconfig.customize_compiler).  In practice, the environment
      variables are useful e.g. to quickly generate a debug build (e.g. by
      setting CFLAGS=-g), but Pybind11Extension currently unconditionally
      overwrites this with -g0.
      
      Instead, check the environment variables and only insert -g0 if not
      overridden by them.
      b11ff912
  20. 07 Nov, 2021 1 commit
  21. 29 Oct, 2021 1 commit
    • Jason Rhinelander's avatar
      feat: allow kw-only args after a py::args (#3402) · e7c9753f
      Jason Rhinelander authored
      
      
      * Simply has_kw_only_args handling
      
      This simplifies tracking the number of kw-only args by instead tracking
      the number of positional arguments (which is really what we care about
      everywhere this is used).
      
      * Allow keyword-only arguments to follow py::args
      
      This removes the constraint that py::args has to be last (or
      second-last, with py::kwargs) and instead makes py::args imply
      py::kw_only for any remaining arguments, allowing you to bind a function
      that works the same way as a Python function such as:
      
          def f(a, *args, b):
              return a * b + sum(args)
      
          f(10, 1, 2, 3, b=20)  # == 206
      
      With this change, you can bind such a function using:
      
          m.def("f", [](int a, py::args args, int b) { /* ... */ },
              "a"_a, "b"_a);
      
      Or, to be more explicit about the keyword-only arguments:
      
          m.def("g", [](int a, py::args args, int b) { /* ... */ },
              "a"_a, py::kw_only{}, "b"_a);
      
      (The only difference between the two is that the latter will fail at
      binding time if the `kw_only{}` doesn't match the `py::args` position).
      
      This doesn't affect backwards compatibility at all because, currently,
      you can't have a py::args anywhere except the end/2nd-last.
      
      * Take args/kwargs by const lvalue ref
      Co-authored-by: default avatarHenry Schreiner <HenrySchreinerIII@gmail.com>
      Co-authored-by: default avatarHenry Schreiner <HenrySchreinerIII@gmail.com>
      e7c9753f
  22. 26 Oct, 2021 2 commits
    • Henry Schreiner's avatar
      fix: improve support for Python 3.11-dev (#3368) · e7e2c79f
      Henry Schreiner authored
      * ci: support Python 3.11-dev
      
      Also update 3.10 to final, better PyPy usage
      
      * fix: use PyFrame_GetCode on Python 3.9+
      
      * ci: some bitiness of pypy not supported on win
      
      * chore: update CMake support to 3.22rc1 to quiet warning
      
      * fix: use dev version of py to fix Py 3.11
      
      * tests: print proper Eigen version
      
      * ci: include pypy2, not sure why
      
      * ci: avoid running on Python 3.11 for now
      
      * ci: fix runs
      
      * ci: simpler PyPy usage, drop unmaintained scipy + pypy index
      
      * ci: only binary numpy, wait on pypy 3.8
      
      * refactor: address review
      e7e2c79f
    • Ryan Cahoon's avatar
      fix: the types for return_value_policy_override in optional_caster (#3376) · c2d3e220
      Ryan Cahoon authored
      
      
      * fix: the types for return_value_policy_override in optional_caster
      
      `return_value_policy_override` was not being applied correctly in
      `optional_caster` in two ways:
      - The `is_lvalue_reference` condition referenced `T`, which was the
      `optional<T>` type parameter from the class, when it should have used `T_`,
      which was the parameter to the `cast` function. `T_` can potentially be a
      reference type, but `T` will never be.
      - The type parameter passed to `return_value_policy_override` should be
      `T::value_type`, not `T`. This matches the way that the other STL container
      type casters work.
      
      The result of these issues was that a method/property definition which used a
      `reference` or `reference_internal` return value policy would create a Python
      value that's bound by reference to a temporary C++ object, resulting in
      undefined behavior. For reasons that I was not able to figure out fully, it
      seems like this causes problems when using old versions of `boost::optional`,
      but not with recent versions of `boost::optional` or the `libstdc++`
      implementation of `std::optional`. The issue (that the override to
      `return_value_policy::move` is never being applied) is present for all
      implementations, it just seems like that somehow doesn't result in problems for
      the some implementation of `optional`. This change includes a regression type
      with a custom optional-like type which was able to reproduce the issue.
      
      Part of the issue with using the wrong types may have stemmed from the type
      variables `T` and `T_` having very similar names. This also changes the type
      variables in `optional_caster` to use slightly more descriptive names, which
      also more closely follow the naming convention used by the other STL casters.
      
      Fixes #3330
      
      * Fix clang-tidy complaints
      
      * Add missing NOLINT
      
      * Apply a couple more fixes
      
      * fix: support GCC 4.8
      
      * tests: avoid warning about unknown compiler for compilers missing C++17
      
      * Remove unneeded test module attribute
      
      * Change test enum to have more unique int values
      Co-authored-by: default avatarAaron Gokaslan <skylion.aaron@gmail.com>
      Co-authored-by: default avatarHenry Schreiner <HenrySchreinerIII@gmail.com>
      c2d3e220
  23. 22 Oct, 2021 1 commit
  24. 19 Oct, 2021 1 commit
  25. 11 Oct, 2021 2 commits
    • Ralf W. Grosse-Kunstleve's avatar
      Correct options on Eigen::MappedSparseMatrix & adding MSVC C4127 suppression... · 7c580586
      Ralf W. Grosse-Kunstleve authored
      Correct options on Eigen::MappedSparseMatrix & adding MSVC C4127 suppression around Eigen includes. (#3352)
      
      * Adding MSVC C4127 suppression around Eigen includes.
      
      * For MSVC 2015 only: also adding the C4127 suppression to test_eigen.cpp
      
      * Copying original change from PR #3343, with extra line breaks to not run past 99 columns (our desired but currently not enforced limit).
      7c580586
    • Bruce Merry's avatar
      Fix make_key_iterator/make_value_iterator for prvalue iterators (#3348) · 8a7c266d
      Bruce Merry authored
      * Add a test showing a flaw in make_key_iterator/make_value_iterator
      
      If the iterator dereference operator returns a value rather than a
      reference (and that pair also does not *contain* references),
      make_key_iterator and make_value_iterator will return a reference to a
      temporary, causing a segfault.
      
      * Fix make_key_iterator/make_value_iterator for prvalue iterators
      
      If an iterator returns a pair<T1, T2> rather than a reference to a pair
      or a pair of references, make_key_iterator and make_value_iterator would
      return a reference to a temporary, typically leading to a segfault. This
      is because the value category of member access to a prvalue is an
      xvalue, not a prvalue, so decltype produces an rvalue reference type.
      Fix the type calculation to handle this case.
      
      I also removed some decltype parentheses that weren't needed, either
      because the expression isn't one of the special cases for decltype or
      because decltype was only used for SFINAE. Hopefully that makes the code
      a bit more readable.
      
      Closes #3347
      
      * Attempt a workaround for nvcc
      8a7c266d
  26. 08 Oct, 2021 1 commit
  27. 04 Oct, 2021 2 commits
  28. 01 Oct, 2021 1 commit
    • Bruce Merry's avatar
      feat: add `.keys` and `.values` to bind_map (#3310) · b3573ac9
      Bruce Merry authored
      
      
      * Add `.keys` and `.values` to bind_map
      
      Both of these implement views (rather than just iterators), and `.items`
      is also upgraded to a view. In practical terms, this allows a view to be
      iterated multiple times and have its size taken, neither of which works
      with an iterator.
      
      The views implement `__len__`, `__iter__`, and the keys view implements
      `__contains__`. Testing membership also works in item and value views
      because Python falls back to iteration. This won't be optimal
      for item values since it's linear rather than O(log n) or O(1), but I
      didn't fancy trying to get all the corner cases to match Python
      behaviour (tuple of wrong types, wrong length tuple, not a tuple etc).
      
      Missing relative to Python dictionary views is `__reversed__` (only
      added to Python in 3.8). Implementing that could break code that binds
      custom map classes which don't provide `rbegin`/`rend` (at least without
      doing clever things with SFINAE), so I've not tried.
      
      The size increase on my system is 131072 bytes, which is rather large
      (5%) but also suspiciously round (2^17) and makes me suspect some
      quantisation effect.
      
      * bind_map: support any object in __contains__
      
      Add extra overload of `__contains__` (for both the map itself and
      KeysView) which takes an arbitrary object and returns false.
      
      * Take py::object by const reference in __contains__
      
      To keep clang-tidy happy.
      
      * Removing stray `py::` (detected via interactive testing in Google environment).
      Co-authored-by: default avatarRalf W. Grosse-Kunstleve <rwgk@google.com>
      b3573ac9
  29. 24 Sep, 2021 1 commit
    • Jeremy Maitin-Shepard's avatar
      Add `custom_type_setup` attribute (#3287) · 62c4909c
      Jeremy Maitin-Shepard authored
      * Fix `pybind11::object::operator=` to be safe if `*this` is accessible from Python
      
      * Add `custom_type_setup` attribute
      
      This allows for custom modifications to the PyHeapTypeObject prior to
      calling `PyType_Ready`.  This may be used, for example, to define
      `tp_traverse` and `tp_clear` functions.
      62c4909c
  30. 23 Sep, 2021 3 commits
    • Henry Schreiner's avatar
      feat: reapply fixed version of #3271 (#3293) · 21282e64
      Henry Schreiner authored
      * Add make_value_iterator (#3271)
      
      * Add make_value_iterator
      
      This is the counterpart to make_key_iterator, and will allow
      implementing a `value` method in `bind_map` (although doing so is left
      for a subsequent PR).
      
      I made a few design changes to reduce copy-and-paste boilerplate.
      Previously detail::iterator_state had a boolean template parameter to
      indicate whether it was being used for make_iterator or
      make_key_iterator. I replaced the boolean with a class that determines
      how to dereference the iterator. This allows for a generic
      implementation of `__next__`.
      
      I also added the ValueType and Extra... parameters to the iterator_state
      template args, because I think it was a bug that they were missing: if
      make_iterator is called twice with different values of these, only the
      first set has effect (because the state class is only registered once).
      There is still a potential issue in that the *values* of the extra
      arguments are latched on the first call, but since most policies are
      empty classes this should be even less common.
      
      * Add some remove_cv_t to appease clang-tidy
      
      * Make iterator_access and friends take reference
      
      For some reason I'd accidentally made it take a const value, which
      caused some issues with third-party packages.
      
      * Another attempt to remove remove_cv_t from iterators
      
      Some of the return types were const (non-reference) types because of the
      pecularities of decltype: `decltype((*it).first)` is the *declared* type
      of the member of the pair, rather than the type of the expression. So if
      the reference type of the iterator is `pair<const int, int> &`, then the
      decltype is `const int`. Wrapping an extra set of parentheses to form
      `decltype(((*it).first))` would instead give `const int &`.
      
      This means that the existing make_key_iterator actually returns by value
      from `__next__`, rather than by reference. Since for mapping types, keys
      are always const, this probably hasn't been noticed, but it will affect
      make_value_iterator if the Python code tries to mutate the returned
      objects. I've changed things to use double parentheses so that
      make_iterator, make_key_iterator and make_value_iterator should now all
      return the reference type of the iterator. I'll still need to add a test
      for that; for now I'm just checking whether I can keep Clang-Tidy happy.
      
      * Add back some NOLINTNEXTLINE to appease Clang-Tidy
      
      This is favoured over using remove_cv_t because in some cases a const
      value return type is deliberate (particularly for Eigen).
      
      * Add a unit test for iterator referencing
      
      Ensure that make_iterator, make_key_iterator and make_value_iterator
      return references to the container elements, rather than copies. The
      test for make_key_iterator fails to compile on master, which gives me
      confidence that this branch has fixed it.
      
      * Make the iterator_access etc operator() const
      
      I'm actually a little surprised it compiled at all given that the
      operator() is called on a temporary, but I don't claim to fully
      understand all the different value types in C++11.
      
      * Attempt to work around compiler bugs
      
      https://godbolt.org/
      
       shows an example where ICC gets the wrong result
      for a decltype used as the default for a template argument, and CI also
      showed problems with PGI. This is a shot in the dark to see if it fixes
      things.
      
      * Make a test constructor explicit (Clang-Tidy)
      
      * Fix unit test on GCC 4.8.5
      
      It seems to require the arguments to the std::pair constructor to be
      implicitly convertible to the types in the pair, rather than just
      requiring is_constructible.
      
      * Remove DOXYGEN_SHOULD_SKIP_THIS guards
      
      Now that a complex decltype expression has been replaced by a simpler
      nested type, I'm hoping Doxygen will be able to build it without issues.
      
      * Add comment to explain iterator_state template params
      
      * fix: regression in #3271
      Co-authored-by: default avatarBruce Merry <1963944+bmerry@users.noreply.github.com>
      21282e64
    • Henry Schreiner's avatar
      5f46e47d
    • Henry Schreiner's avatar
      Revert "Add make_value_iterator (#3271)" · 2fa3fcfd
      Henry Schreiner authored
      This reverts commit ee0c5ee4.
      2fa3fcfd
  31. 22 Sep, 2021 1 commit
    • Henry Schreiner's avatar
      feat: Slice allowing None with py::object or std::optional (#1101) · b06a6f4f
      Henry Schreiner authored
      * Adding nullptr slices
      
      Using example from #1095
      
      Some fixes from @wjakob's review
      
      Stop clang-tidy from complaining
      
      New proposal for py::slice constructor
      
      Eric's suggested changes: simplify testing; shift def's
      
      * chore: drop MSVC pragma (hopefully unneeded)
      
      * Apply suggestions from code review
      b06a6f4f
  32. 21 Sep, 2021 1 commit
    • Bruce Merry's avatar
      Add make_value_iterator (#3271) · ee0c5ee4
      Bruce Merry authored
      * Add make_value_iterator
      
      This is the counterpart to make_key_iterator, and will allow
      implementing a `value` method in `bind_map` (although doing so is left
      for a subsequent PR).
      
      I made a few design changes to reduce copy-and-paste boilerplate.
      Previously detail::iterator_state had a boolean template parameter to
      indicate whether it was being used for make_iterator or
      make_key_iterator. I replaced the boolean with a class that determines
      how to dereference the iterator. This allows for a generic
      implementation of `__next__`.
      
      I also added the ValueType and Extra... parameters to the iterator_state
      template args, because I think it was a bug that they were missing: if
      make_iterator is called twice with different values of these, only the
      first set has effect (because the state class is only registered once).
      There is still a potential issue in that the *values* of the extra
      arguments are latched on the first call, but since most policies are
      empty classes this should be even less common.
      
      * Add some remove_cv_t to appease clang-tidy
      
      * Make iterator_access and friends take reference
      
      For some reason I'd accidentally made it take a const value, which
      caused some issues with third-party packages.
      
      * Another attempt to remove remove_cv_t from iterators
      
      Some of the return types were const (non-reference) types because of the
      pecularities of decltype: `decltype((*it).first)` is the *declared* type
      of the member of the pair, rather than the type of the expression. So if
      the reference type of the iterator is `pair<const int, int> &`, then the
      decltype is `const int`. Wrapping an extra set of parentheses to form
      `decltype(((*it).first))` would instead give `const int &`.
      
      This means that the existing make_key_iterator actually returns by value
      from `__next__`, rather than by reference. Since for mapping types, keys
      are always const, this probably hasn't been noticed, but it will affect
      make_value_iterator if the Python code tries to mutate the returned
      objects. I've changed things to use double parentheses so that
      make_iterator, make_key_iterator and make_value_iterator should now all
      return the reference type of the iterator. I'll still need to add a test
      for that; for now I'm just checking whether I can keep Clang-Tidy happy.
      
      * Add back some NOLINTNEXTLINE to appease Clang-Tidy
      
      This is favoured over using remove_cv_t because in some cases a const
      value return type is deliberate (particularly for Eigen).
      
      * Add a unit test for iterator referencing
      
      Ensure that make_iterator, make_key_iterator and make_value_iterator
      return references to the container elements, rather than copies. The
      test for make_key_iterator fails to compile on master, which gives me
      confidence that this branch has fixed it.
      
      * Make the iterator_access etc operator() const
      
      I'm actually a little surprised it compiled at all given that the
      operator() is called on a temporary, but I don't claim to fully
      understand all the different value types in C++11.
      
      * Attempt to work around compiler bugs
      
      https://godbolt.org/ shows an example where ICC gets the wrong result
      for a decltype used as the default for a template argument, and CI also
      showed problems with PGI. This is a shot in the dark to see if it fixes
      things.
      
      * Make a test constructor explicit (Clang-Tidy)
      
      * Fix unit test on GCC 4.8.5
      
      It seems to require the arguments to the std::pair constructor to be
      implicitly convertible to the types in the pair, rather than just
      requiring is_constructible.
      
      * Remove DOXYGEN_SHOULD_SKIP_THIS guards
      
      Now that a complex decltype expression has been replaced by a simpler
      nested type, I'm hoping Doxygen will be able to build it without issues.
      
      * Add comment to explain iterator_state template params
      ee0c5ee4
  33. 20 Sep, 2021 1 commit