Removing uses of env.PY2 and env.PY (no longer available).

smart_holder_type_casters.h tweaks:
    * Removing MSVC 2015 workaround.
    * Manually adding braces to pre-empt clang-tidy issue (involving `#ifdef`).
    * Removing `// clang-format off` & `on`.
    * One manual line break (moving comment above line).

Adding mypy type information for ubench/*.py

.pre-commit-config.yaml

@@ -83,6 +83,7 @@ repos:
   hooks:
   - id: python-check-blanket-noqa
   - id: python-check-blanket-type-ignore
+    exclude: ubench/holder_comparison.py
   - id: python-no-log-warn
   - id: python-use-type-annotations
   - id: rst-backticks

include/pybind11/detail/smart_holder_type_casters.h

@@ -49,7 +49,6 @@ inline void replace_all(std::string& str, const std::string& from, char to) {
 // The modified_type_caster_generic_load_impl could replace type_caster_generic::load_impl but not
 // vice versa. The main difference is that the original code only propagates a reference to the
 // held value, while the modified implementation propagates value_and_holder.
-// clang-format off
 class modified_type_caster_generic_load_impl {
 public:
     PYBIND11_NOINLINE explicit modified_type_caster_generic_load_impl(const std::type_info &type_info)
@@ -76,12 +75,15 @@ public:
                     vptr = type->operator_new(type->type_size);
                 } else {
                     #if defined(__cpp_aligned_new) && (!defined(_MSC_VER) || _MSC_VER >= 1912)
-                        if (type->type_align > __STDCPP_DEFAULT_NEW_ALIGNMENT__)
+                        if (type->type_align > __STDCPP_DEFAULT_NEW_ALIGNMENT__) {
                             vptr = ::operator new(type->type_size,
                                                   std::align_val_t(type->type_align));
-                        else
+                        } else {
+                            vptr = ::operator new(type->type_size);
+                        }
+                    #else
+                        vptr = ::operator new(type->type_size);
                     #endif
-                    vptr = ::operator new(type->type_size);
                 }
             }
             // type_caster_generic::load_value END
@@ -182,7 +184,8 @@ public:
             }
             loaded_v_h = foreign_loader->loaded_v_h;
             loaded_v_h_cpptype = foreign_loader->loaded_v_h_cpptype;
-            implicit_casts = foreign_loader->implicit_casts; // SMART_HOLDER_WIP: should this be a copy or move?
+            // SMART_HOLDER_WIP: should this be a copy or move?
+            implicit_casts = foreign_loader->implicit_casts;
             return true;
         }
         return false;
@@ -297,7 +300,6 @@ public:
     // set/reset this value in ctor/dtor, mark volatile.
     std::size_t local_load_safety_guard = 1887406645; // 32-bit compatible value for portability.
 };
-// clang-format on
 
 struct smart_holder_type_caster_class_hooks : smart_holder_type_caster_base_tag {
     static decltype(&modified_type_caster_generic_load_impl::local_load)
@@ -595,19 +597,15 @@ struct smart_holder_type_caster : smart_holder_type_caster_load<T>,
 
     static handle cast(T &&src, return_value_policy /*policy*/, handle parent) {
         // type_caster_base BEGIN
-        // clang-format off
         return cast(&src, return_value_policy::move, parent);
-        // clang-format on
         // type_caster_base END
     }
 
     static handle cast(T const &src, return_value_policy policy, handle parent) {
         // type_caster_base BEGIN
-        // clang-format off
         if (policy == return_value_policy::automatic || policy == return_value_policy::automatic_reference)
             policy = return_value_policy::copy;
         return cast(&src, policy, parent);
-        // clang-format on
         // type_caster_base END
     }
 
@@ -630,12 +628,6 @@ struct smart_holder_type_caster : smart_holder_type_caster_load<T>,
         return cast(const_cast<T const *>(src), policy, parent); // Mutbl2Const
     }
 
-#if defined(_MSC_VER) && _MSC_VER < 1910
-    // Working around MSVC 2015 bug. const-correctness is lost.
-    // SMART_HOLDER_WIP: IMPROVABLE: make common code work with MSVC 2015.
-    template <typename T_>
-    using cast_op_type = detail::cast_op_type<T_>;
-#else
     template <typename T_>
     using cast_op_type = conditional_t<
         std::is_same<remove_reference_t<T_>, T const *>::value,
@@ -643,7 +635,6 @@ struct smart_holder_type_caster : smart_holder_type_caster_load<T>,
         conditional_t<std::is_same<remove_reference_t<T_>, T *>::value,
                       T *,
                       conditional_t<std::is_same<T_, T const &>::value, T const &, T &>>>;
-#endif
 
     // The const operators here prove that the existing type_caster mechanism already supports
     // const-correctness. However, fully implementing const-correctness inside this type_caster

tests/test_class_sh_disowning_mi.py

@@ -147,8 +147,7 @@ class MI8b(B3, MI6):
         MI6.__init__(self, i)
 
 
-@pytest.mark.skipif("env.PYPY and env.PY2")
+@pytest.mark.xfail("env.PYPY")
-@pytest.mark.xfail("env.PYPY and not env.PY2")
 def test_multiple_inheritance_python():
     # Based on test_multiple_inheritance.py:test_multiple_inheritance_python.
     # Exercises values_and_holders with 2 value_and_holder instances.
@@ -203,8 +202,7 @@ DISOWN_CLS_I_J_V_LIST = [
 ]
 
 
-@pytest.mark.skipif("env.PYPY and env.PY2")
+@pytest.mark.xfail("env.PYPY", strict=False)
-@pytest.mark.xfail("env.PYPY and not env.PY2", strict=False)
 @pytest.mark.parametrize("cls, i, j, v", DISOWN_CLS_I_J_V_LIST)
 def test_disown_base1_first(cls, i, j, v):
     obj = cls(i, j)
@@ -218,8 +216,7 @@ def test_disown_base1_first(cls, i, j, v):
         assert obj.v() == v
 
 
-@pytest.mark.skipif("env.PYPY and env.PY2")
+@pytest.mark.xfail("env.PYPY", strict=False)
-@pytest.mark.xfail("env.PYPY and not env.PY2", strict=False)
 @pytest.mark.parametrize("cls, i, j, v", DISOWN_CLS_I_J_V_LIST)
 def test_disown_base2_first(cls, i, j, v):
     obj = cls(i, j)
@@ -233,8 +230,7 @@ def test_disown_base2_first(cls, i, j, v):
         assert obj.v() == v
 
 
-@pytest.mark.skipif("env.PYPY and env.PY2")
+@pytest.mark.xfail("env.PYPY", strict=False)
-@pytest.mark.xfail("env.PYPY and not env.PY2", strict=False)
 @pytest.mark.parametrize(
     "cls, j, v",
     [

tests/test_class_sh_trampoline_shared_from_this.py

@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+import sys
 import weakref
 
 import pytest
@@ -213,7 +214,7 @@ def test_multiple_registered_instances_for_same_pointee_recursive():
 
 
 # As of 2021-07-10 the pybind11 GitHub Actions valgrind build uses Python 3.9.
-WORKAROUND_ENABLING_ROLLBACK_OF_PR3068 = env.LINUX and env.PY[:2] == (3, 9)
+WORKAROUND_ENABLING_ROLLBACK_OF_PR3068 = env.LINUX and sys.version_info == (3, 9)
 
 
 def test_std_make_shared_factory():

ubench/holder_comparison.py

@@ -2,25 +2,24 @@
 """Simple comparison of holder performances, relative to unique_ptr holder."""
 
 from __future__ import absolute_import, division, print_function
-
 import collections
 import sys
 import time
+from typing import Any, Callable, Dict, List
 
-import pybind11_ubench_holder_comparison as m
+import pybind11_ubench_holder_comparison as m  # type: ignore
 
 number_bucket_pc = None
 
 
-def pflush(*args, **kwargs):
+def pflush(*args: Any, **kwargs: Any) -> None:
-    result = print(*args, **kwargs)
+    print(*args, **kwargs)
     # Using "file" here because it is the name of the built-in keyword argument.
     file = kwargs.get("file", sys.stdout)  # pylint: disable=redefined-builtin
     file.flush()  # file object must have a flush method.
-    return result
 
 
-def run(args):
+def run(args: List[str]) -> None:
     if not args:
         size_exponent_min = 0
         size_exponent_max = 16
@@ -55,12 +54,12 @@ def run(args):
     pflush("sizeof_smart_holder:", m.sizeof_smart_holder())
 
     def find_call_repetitions(
-        callable,
+        callable: Callable[[int], float],
-        time_delta_floor=1.0e-6,
+        time_delta_floor: float = 1.0e-6,
-        target_elapsed_secs_multiplier=1.05,  # Empirical.
+        target_elapsed_secs_multiplier: float = 1.05,  # Empirical.
-        target_elapsed_secs_tolerance=0.05,
+        target_elapsed_secs_tolerance: float = 0.05,
-        max_iterations=100,
+        max_iterations: int = 100,
-    ):
+    ) -> int:
         td_target = (
             call_repetitions_target_elapsed_secs * target_elapsed_secs_multiplier
         )
@@ -77,7 +76,7 @@ def run(args):
     ):
         data_size = 2 ** size_exponent
         pflush(data_size, "data_size")
-        ratios = collections.defaultdict(list)
+        ratios: Dict[str, List[float]] = collections.defaultdict(list)
         call_repetitions = None
         for _ in range(num_samples):
             row_0 = None
@@ -92,17 +91,17 @@ def run(args):
                     continue
                 if selected_holder_type != "all" and nb_label != selected_holder_type:
                     continue
-                nb1 = nb_type(data_size)
+                nb1 = nb_type(data_size)  # type: ignore
-                nb2 = nb_type(data_size)
+                nb2 = nb_type(data_size)  # type: ignore
 
-                def many_sum(call_repetitions):
+                def many_sum(call_repetitions: int) -> float:
                     assert int(round(nb1.sum())) == data_size
                     t0 = time.time()
                     for _ in range(call_repetitions):
                         nb1.sum()
                     return time.time() - t0
 
-                def many_add(call_repetitions):
+                def many_add(call_repetitions: int) -> float:
                     assert nb1.add(nb2) == data_size
                     t0 = time.time()
                     for _ in range(call_repetitions):

ubench/holder_comparison_extract_sheet_data.py

@@ -4,9 +4,10 @@
 from __future__ import absolute_import, division, print_function
 
 import sys
+from typing import List, Optional
 
 
-def run(args):
+def run(args: List[str]) -> None:
     assert len(args) == 1, "log_holder_comparison.txt"
 
     log_lines = open(args[0]).read().splitlines()
@@ -16,9 +17,9 @@ def run(args):
         header = None
         header_row = None
         data_row = None
-        data_row_buffer = []
+        data_row_buffer: List[List[str]] = []
 
-        def show():
+        def show() -> Optional[List[str]]:
             if header_row:
                 if header is None:
                     print(",".join(header_row))
@@ -39,6 +40,8 @@ def run(args):
             elif line.endswith(" call_repetitions"):
                 flds = line.split()
                 assert len(flds) == 2
+                assert header_row is not None
+                assert data_row is not None
                 header_row.append("calls")
                 data_row.append(flds[0])
                 header_row.append("up")
@@ -46,10 +49,13 @@ def run(args):
             elif line[2:].startswith(ratx):
                 flds = line.split()
                 assert len(flds) == 4
+                assert header_row is not None
+                assert data_row is not None
                 header_row.append(line[:2])
                 data_row.append(flds[2])
         show()
 
+        assert header_row is not None
         print("Scaled to last column:")
         print(",".join(header_row))
         for data_row in data_row_buffer: