chore: drop Python 3.5 (#3719)

* chore: drop Python 3.5 support

* chore: more fstrings with flynt's help

* ci: drop Python 3.5

* chore: bump dependency versions

* docs: touch up py::args

* tests: remove deprecation warning

* Ban smartquotes

* Very minor tweaks (by-product of reviewing PR #3719).

Co-authored-by: Aaron Gokaslan <skylion.aaron@gmail.com>
Co-authored-by: Ralf W. Grosse-Kunstleve <rwgk@google.com>

.github/CONTRIBUTING.md

@@ -93,11 +93,10 @@ cmake --build build -j4
 
 Tips:
 
-* You can use `virtualenv` (from PyPI) instead of `venv` (which is Python 3
+* You can use `virtualenv` (faster, from PyPI) instead of `venv`.
-  only).
 * You can select any name for your environment folder; if it contains "env" it
   will be ignored by git.
-* If you don’t have CMake 3.14+, just add “cmake” to the pip install command.
+* If you don't have CMake 3.14+, just add "cmake" to the pip install command.
 * You can use `-DPYBIND11_FINDPYTHON=ON` to use FindPython on CMake 3.12+
 * In classic mode, you may need to set `-DPYTHON_EXECUTABLE=/path/to/python`.
   FindPython uses `-DPython_ROOT_DIR=/path/to` or
@@ -105,7 +104,7 @@ Tips:
 
 ### Configuration options
 
-In CMake, configuration options are given with “-D”. Options are stored in the
+In CMake, configuration options are given with "-D". Options are stored in the
 build directory, in the `CMakeCache.txt` file, so they are remembered for each
 build directory. Two selections are special - the generator, given with `-G`,
 and the compiler, which is selected based on environment variables `CXX` and
@@ -115,7 +114,7 @@ after the initial run.
 The valid options are:
 
 * `-DCMAKE_BUILD_TYPE`: Release, Debug, MinSizeRel, RelWithDebInfo
-* `-DPYBIND11_FINDPYTHON=ON`: Use CMake 3.12+’s FindPython instead of the
+* `-DPYBIND11_FINDPYTHON=ON`: Use CMake 3.12+'s FindPython instead of the
   classic, deprecated, custom FindPythonLibs
 * `-DPYBIND11_NOPYTHON=ON`: Disable all Python searching (disables tests)
 * `-DBUILD_TESTING=ON`: Enable the tests
@@ -257,7 +256,7 @@ The report is sent to stderr; you can pipe it into a file if you wish.
 ### Build recipes
 
 This builds with the Intel compiler (assuming it is in your path, along with a
-recent CMake and Python 3):
+recent CMake and Python):
 
 ```bash
 python3 -m venv venv

.github/workflows/ci.yml

@@ -15,6 +15,8 @@ concurrency:
 
 env:
   PIP_ONLY_BINARY: numpy
+  FORCE_COLOR: 3
+  PYTEST_TIMEOUT: 300
 
 jobs:
   # This is the "main" test suite, which tests a large number of different
@@ -25,7 +27,6 @@ jobs:
       matrix:
         runs-on: [ubuntu-latest, windows-2022, macos-latest]
         python:
-        - '3.5'
         - '3.6'
         - '3.9'
         - '3.10'
@@ -167,7 +168,7 @@ jobs:
     # setuptools
     - name: Setuptools helpers test
       run: pytest tests/extra_setuptools
-      if: "!(matrix.python == '3.5' && matrix.runs-on == 'windows-2022')"
+      if: "!(matrix.runs-on == 'windows-2022')"
 
 
   deadsnakes:
@@ -624,9 +625,9 @@ jobs:
 
   # This tests an "install" with the CMake tools
   install-classic:
-    name: "🐍 3.5 • Debian • x86 •  Install"
+    name: "🐍 3.7 • Debian • x86 •  Install"
     runs-on: ubuntu-latest
-    container: i386/debian:stretch
+    container: i386/debian:buster
 
     steps:
     - uses: actions/checkout@v1
@@ -635,7 +636,7 @@ jobs:
       run: |
         apt-get update
         apt-get install -y git make cmake g++ libeigen3-dev python3-dev python3-pip
-        pip3 install "pytest==3.1.*"
+        pip3 install "pytest==6.*"
 
     - name: Configure for install
       run: >
@@ -704,12 +705,10 @@ jobs:
       fail-fast: false
       matrix:
         python:
-        - 3.5
         - 3.6
         - 3.7
         - 3.8
         - 3.9
-        - pypy-3.6
 
         include:
           - python: 3.9
@@ -810,7 +809,7 @@ jobs:
       fail-fast: false
       matrix:
         python:
-          - 3.5
+          - 3.6
           - 3.7
         std:
           - 14

.pre-commit-config.yaml

@@ -15,7 +15,7 @@
 repos:
 # Standard hooks
 - repo: https://github.com/pre-commit/pre-commit-hooks
-  rev: v4.1.0
+  rev: "v4.1.0"
   hooks:
   - id: check-added-large-files
   - id: check-case-conflict
@@ -32,26 +32,26 @@ repos:
 
 # Upgrade old Python syntax
 - repo: https://github.com/asottile/pyupgrade
-  rev: v2.31.0
+  rev: "v2.31.0"
   hooks:
   - id: pyupgrade
-    args: [--py3-plus]
+    args: [--py36-plus]
 
 # Nicely sort includes
 - repo: https://github.com/PyCQA/isort
-  rev: 5.10.1
+  rev: "5.10.1"
   hooks:
   - id: isort
 
 # Black, the code formatter, natively supports pre-commit
 - repo: https://github.com/psf/black
-  rev: 22.1.0 # Keep in sync with blacken-docs
+  rev: "22.1.0" # Keep in sync with blacken-docs
   hooks:
   - id: black
 
 # Also code format the docs
 - repo: https://github.com/asottile/blacken-docs
-  rev: v1.12.1
+  rev: "v1.12.1"
   hooks:
   - id: blacken-docs
     additional_dependencies:
@@ -59,32 +59,37 @@ repos:
 
 # Changes tabs to spaces
 - repo: https://github.com/Lucas-C/pre-commit-hooks
-  rev: v1.1.11
+  rev: "v1.1.11"
   hooks:
   - id: remove-tabs
 
+- repo: https://github.com/sirosen/texthooks
+  rev: "0.2.2"
+  hooks:
+  - id: fix-ligatures
+  - id: fix-smartquotes
+
 # Autoremoves unused imports
 - repo: https://github.com/hadialqattan/pycln
-  rev: v1.1.0
+  rev: "v1.1.0"
   hooks:
   - id: pycln
 
 # Checking for common mistakes
 - repo: https://github.com/pre-commit/pygrep-hooks
-  rev: v1.9.0
+  rev: "v1.9.0"
   hooks:
   - id: python-check-blanket-noqa
   - id: python-check-blanket-type-ignore
   - id: python-no-log-warn
-  # Python 3.6
+  - id: python-use-type-annotations
-  # - id: python-use-type-annotations
   - id: rst-backticks
   - id: rst-directive-colons
   - id: rst-inline-touching-normal
 
 # Flake8 also supports pre-commit natively (same author)
 - repo: https://github.com/PyCQA/flake8
-  rev: 4.0.1
+  rev: "4.0.1"
   hooks:
   - id: flake8
     additional_dependencies: &flake8_dependencies
@@ -94,14 +99,14 @@ repos:
 
 # Automatically remove noqa that are not used
 - repo: https://github.com/asottile/yesqa
-  rev: v1.3.0
+  rev: "v1.3.0"
   hooks:
   - id: yesqa
     additional_dependencies: *flake8_dependencies
 
 # CMake formatting
 - repo: https://github.com/cheshirekow/cmake-format-precommit
-  rev: v0.6.13
+  rev: "v0.6.13"
   hooks:
   - id: cmake-format
     additional_dependencies: [pyyaml]
@@ -110,7 +115,7 @@ repos:
 
 # Check static types with mypy
 - repo: https://github.com/pre-commit/mirrors-mypy
-  rev: v0.931
+  rev: "v0.931"
   hooks:
   - id: mypy
     args: [--show-error-codes]
@@ -128,7 +133,7 @@ repos:
 
 # Check for spelling
 - repo: https://github.com/codespell-project/codespell
-  rev: v2.1.0
+  rev: "v2.1.0"
   hooks:
   - id: codespell
     exclude: ".supp$"
@@ -136,7 +141,7 @@ repos:
 
 # Check for common shell mistakes
 - repo: https://github.com/shellcheck-py/shellcheck-py
-  rev: v0.8.0.4
+  rev: "v0.8.0.4"
   hooks:
   - id: shellcheck
 

README.rst

@@ -32,9 +32,9 @@ this heavy machinery has become an excessively large and unnecessary
 dependency.
 
 Think of this library as a tiny self-contained version of Boost.Python
-with everything stripped away that isn’t relevant for binding
+with everything stripped away that isn't relevant for binding
 generation. Without comments, the core header files only require ~4K
-lines of code and depend on Python (3.5+, or PyPy) and the C++
+lines of code and depend on Python (3.6+, or PyPy) and the C++
 standard library. This compact implementation was possible thanks to
 some of the new C++11 language features (specifically: tuples, lambda
 functions and variadic templates). Since its creation, this library has
@@ -78,8 +78,8 @@ Goodies
 In addition to the core functionality, pybind11 provides some extra
 goodies:
 
-- Python 3.5+, and PyPy3 7.3 are supported with an implementation-agnostic
+- Python 3.6+, and PyPy3 7.3 are supported with an implementation-agnostic
-  interface (pybind11 2.9 was the last version to support Python 2).
+  interface (pybind11 2.9 was the last version to support Python 2 and 3.5).
 
 - It is possible to bind C++11 lambda functions with captured
   variables. The lambda capture data is stored inside the resulting
@@ -88,8 +88,8 @@ goodies:
 - pybind11 uses C++11 move constructors and move assignment operators
   whenever possible to efficiently transfer custom data types.
 
-- It’s easy to expose the internal storage of custom data types through
+- It's easy to expose the internal storage of custom data types through
-  Pythons’ buffer protocols. This is handy e.g. for fast conversion
+  Pythons' buffer protocols. This is handy e.g. for fast conversion
   between C++ matrix classes like Eigen and NumPy without expensive
   copy operations.
 
@@ -119,7 +119,7 @@ goodies:
 Supported compilers
 -------------------
 
-1. Clang/LLVM 3.3 or newer (for Apple Xcode’s clang, this is 5.0.0 or
+1. Clang/LLVM 3.3 or newer (for Apple Xcode's clang, this is 5.0.0 or
    newer)
 2. GCC 4.8 or newer
 3. Microsoft Visual Studio 2015 Update 3 or newer

docs/advanced/cast/overview.rst

@@ -167,5 +167,4 @@ as arguments and return values, refer to the section on binding :ref:`classes`.
 +------------------------------------+---------------------------+-----------------------------------+
 
 .. [#] ``std::filesystem::path`` is converted to ``pathlib.Path`` and
-   ``os.PathLike`` is converted to ``std::filesystem::path``, but this requires
+   ``os.PathLike`` is converted to ``std::filesystem::path``.
-   Python 3.6 (for ``__fspath__`` support).

docs/advanced/functions.rst

@@ -372,7 +372,7 @@ like so:
 Keyword-only arguments
 ======================
 
-Python 3 introduced keyword-only arguments by specifying an unnamed ``*``
+Python implements keyword-only arguments by specifying an unnamed ``*``
 argument in a function definition:
 
 .. code-block:: python
@@ -395,19 +395,18 @@ argument annotations when registering the function:
     m.def("f", [](int a, int b) { /* ... */ },
           py::arg("a"), py::kw_only(), py::arg("b"));
 
-Note that you currently cannot combine this with a ``py::args`` argument.  This
-feature does *not* require Python 3 to work.
-
 .. versionadded:: 2.6
 
-As of pybind11 2.9, a ``py::args`` argument implies that any following arguments
+A ``py::args`` argument implies that any following arguments are keyword-only,
-are keyword-only, as if ``py::kw_only()`` had been specified in the same
+as if ``py::kw_only()`` had been specified in the same relative location of the
-relative location of the argument list as the ``py::args`` argument.  The
+argument list as the ``py::args`` argument.  The ``py::kw_only()`` may be
-``py::kw_only()`` may be included to be explicit about this, but is not
+included to be explicit about this, but is not required.
-required.  (Prior to 2.9 ``py::args`` may only occur at the end of the argument
+
-list, or immediately before a ``py::kwargs`` argument at the end).
+.. versionchanged:: 2.9
+   This can now be combined with ``py::args``. Before, ``py::args`` could only
+   occur at the end of the argument list, or immediately before a ``py::kwargs``
+   argument at the end.
 
-.. versionadded:: 2.9
 
 Positional-only arguments
 =========================

docs/advanced/pycpp/numpy.rst

@@ -395,7 +395,7 @@ uses of ``py::array``:
 Ellipsis
 ========
 
-Python 3 provides a convenient ``...`` ellipsis notation that is often used to
+Python provides a convenient ``...`` ellipsis notation that is often used to
 slice multidimensional arrays. For instance, the following snippet extracts the
 middle dimensions of a tensor with the first and last index set to zero.
 

docs/benchmark.py

@@ -11,20 +11,20 @@ def generate_dummy_code_pybind11(nclasses=10):
     bindings = ""
 
     for cl in range(nclasses):
-        decl += "class cl%03i;\n" % cl
+        decl += f"class cl{cl:03};\n"
     decl += "\n"
 
     for cl in range(nclasses):
-        decl += "class cl%03i {\n" % cl
+        decl += f"class {cl:03} {{\n"
         decl += "public:\n"
-        bindings += '    py::class_<cl%03i>(m, "cl%03i")\n' % (cl, cl)
+        bindings += f'    py::class_<cl{cl:03}>(m, "cl{cl:03}")\n'
         for fn in range(nfns):
             ret = random.randint(0, nclasses - 1)
             params = [random.randint(0, nclasses - 1) for i in range(nargs)]
-            decl += "    cl%03i *fn_%03i(" % (ret, fn)
+            decl += f"    cl{ret:03} *fn_{fn:03}("
-            decl += ", ".join("cl%03i *" % p for p in params)
+            decl += ", ".join(f"cl{p:03} *" for p in params)
             decl += ");\n"
-            bindings += '        .def("fn_%03i", &cl%03i::fn_%03i)\n' % (fn, cl, fn)
+            bindings += f'        .def("fn_{fn:03}", &cl{cl:03}::fn_{fn:03})\n'
         decl += "};\n\n"
         bindings += "        ;\n"
 
@@ -42,23 +42,20 @@ def generate_dummy_code_boost(nclasses=10):
     bindings = ""
 
     for cl in range(nclasses):
-        decl += "class cl%03i;\n" % cl
+        decl += f"class cl{cl:03};\n"
     decl += "\n"
 
     for cl in range(nclasses):
         decl += "class cl%03i {\n" % cl
         decl += "public:\n"
-        bindings += '    py::class_<cl%03i>("cl%03i")\n' % (cl, cl)
+        bindings += f'    py::class_<cl{cl:03}>("cl{cl:03}")\n'
         for fn in range(nfns):
             ret = random.randint(0, nclasses - 1)
             params = [random.randint(0, nclasses - 1) for i in range(nargs)]
-            decl += "    cl%03i *fn_%03i(" % (ret, fn)
+            decl += f"    cl{ret:03} *fn_{fn:03}("
-            decl += ", ".join("cl%03i *" % p for p in params)
+            decl += ", ".join(f"cl{p:03} *" for p in params)
             decl += ");\n"
-            bindings += (
+            bindings += f'        .def("fn_{fn:03}", &cl{cl:03}::fn_{fn:03}, py::return_value_policy<py::manage_new_object>())\n'
-                '        .def("fn_%03i", &cl%03i::fn_%03i, py::return_value_policy<py::manage_new_object>())\n'
-                % (fn, cl, fn)
-            )
         decl += "};\n\n"
         bindings += "        ;\n"
 

docs/changelog.rst

@@ -800,7 +800,7 @@ Packaging / building improvements:
   `#2338 <https://github.com/pybind/pybind11/pull/2338>`_ and
   `#2370 <https://github.com/pybind/pybind11/pull/2370>`_
 
-  * Full integration with CMake’s C++ standard system and compile features
+  * Full integration with CMake's C++ standard system and compile features
     replaces ``PYBIND11_CPP_STANDARD``.
 
   * Generated config file is now portable to different Python/compiler/CMake

docs/compiling.rst

@@ -417,10 +417,10 @@ existing targets instead:
 
 .. code-block:: cmake
 
-    cmake_minimum_required(VERSION 3.15...3.19)
+    cmake_minimum_required(VERSION 3.15...3.22)
     project(example LANGUAGES CXX)
 
-    find_package(Python COMPONENTS Interpreter Development REQUIRED)
+    find_package(Python 3.6 COMPONENTS Interpreter Development REQUIRED)
     find_package(pybind11 CONFIG REQUIRED)
     # or add_subdirectory(pybind11)
 
@@ -433,9 +433,8 @@ algorithms from the CMake invocation, with ``-DPYBIND11_FINDPYTHON=ON``.
 
 .. warning::
 
-    If you use FindPython2 and FindPython3 to dual-target Python, use the
+    If you use FindPython to multi-target Python versions, use the individual
-    individual targets listed below, and avoid targets that directly include
+    targets listed below, and avoid targets that directly include Python parts.
-    Python parts.
 
 There are `many ways to hint or force a discovery of a specific Python
 installation <https://cmake.org/cmake/help/latest/module/FindPython.html>`_),

docs/conf.py

@@ -344,9 +344,9 @@ def generate_doxygen_xml(app):
         subprocess.call(["doxygen", "--version"])
         retcode = subprocess.call(["doxygen"], cwd=app.confdir)
         if retcode < 0:
-            sys.stderr.write("doxygen error code: {}\n".format(-retcode))
+            sys.stderr.write(f"doxygen error code: {-retcode}\n")
     except OSError as e:
-        sys.stderr.write("doxygen execution failed: {}\n".format(e))
+        sys.stderr.write(f"doxygen execution failed: {e}\n")
 
 
 def prepare(app):

docs/faq.rst

@@ -145,7 +145,7 @@ using C++14 template metaprogramming.
 
 .. _`faq:hidden_visibility`:
 
-"‘SomeClass’ declared with greater visibility than the type of its field ‘SomeClass::member’ [-Wattributes]"
+"'SomeClass' declared with greater visibility than the type of its field 'SomeClass::member' [-Wattributes]"
 ============================================================================================================
 
 This error typically indicates that you are compiling without the required

docs/requirements.txt

@@ -1,5 +1,5 @@
-breathe==4.31.0
+breathe==4.32.0
-sphinx==3.5.4
+sphinx==4.4.0
 sphinx_rtd_theme==1.0.0
-sphinxcontrib-moderncmakedomain==3.19
+sphinxcontrib-moderncmakedomain==3.21.4
-sphinxcontrib-svg2pdfconverter==1.1.1
+sphinxcontrib-svg2pdfconverter==1.2.0

docs/upgrade.rst

@@ -524,7 +524,7 @@ include a declaration of the form:
 
     PYBIND11_DECLARE_HOLDER_TYPE(T, std::shared_ptr<T>)
 
-Continuing to do so won’t cause an error or even a deprecation warning,
+Continuing to do so won't cause an error or even a deprecation warning,
 but it's completely redundant.
 
 

include/pybind11/cast.h

@@ -1585,7 +1585,7 @@ unpacking_collector<policy> collect_arguments(Args &&...args) {
 template <typename Derived>
 template <return_value_policy policy, typename... Args>
 object object_api<Derived>::operator()(Args &&...args) const {
-#if !defined(NDEBUG) && PY_VERSION_HEX >= 0x03060000
+#ifndef NDEBUG
     if (!PyGILState_Check()) {
         pybind11_fail("pybind11::object_api<>::operator() PyGILState_Check() failure.");
     }

include/pybind11/chrono.h

@@ -18,17 +18,6 @@
 #include <datetime.h>
 #include <mutex>
 
-// Backport the PyDateTime_DELTA functions from Python3.3 if required
-#ifndef PyDateTime_DELTA_GET_DAYS
-#    define PyDateTime_DELTA_GET_DAYS(o) (((PyDateTime_Delta *) o)->days)
-#endif
-#ifndef PyDateTime_DELTA_GET_SECONDS
-#    define PyDateTime_DELTA_GET_SECONDS(o) (((PyDateTime_Delta *) o)->seconds)
-#endif
-#ifndef PyDateTime_DELTA_GET_MICROSECONDS
-#    define PyDateTime_DELTA_GET_MICROSECONDS(o) (((PyDateTime_Delta *) o)->microseconds)
-#endif
-
 PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
 PYBIND11_NAMESPACE_BEGIN(detail)
 

include/pybind11/detail/common.h

@@ -211,8 +211,8 @@
 #endif
 
 #include <Python.h>
-#if PY_VERSION_HEX < 0x030500f0
+#if PY_VERSION_HEX < 0x03060000
-#    error "PYTHON 2 IS NO LONGER SUPPORTED. pybind11 v2.9 was the last to support Python 2."
+#    error "PYTHON < 3.6 IS UNSUPPORTED. pybind11 v2.9 was the last to support Python 2 and 3.5."
 #endif
 #include <frameobject.h>
 #include <pythread.h>
@@ -301,15 +301,6 @@
     extern "C" PYBIND11_MAYBE_UNUSED PYBIND11_EXPORT PyObject *PyInit_##name();                   \
     extern "C" PYBIND11_EXPORT PyObject *PyInit_##name()
 
-#if PY_VERSION_HEX >= 0x03050000 && PY_VERSION_HEX < 0x03050200
-extern "C" {
-struct _Py_atomic_address {
-    void *value;
-};
-PyAPI_DATA(_Py_atomic_address) _PyThreadState_Current;
-}
-#endif
-
 #define PYBIND11_TRY_NEXT_OVERLOAD ((PyObject *) 1) // special failure return code
 #define PYBIND11_STRINGIFY(x) #x
 #define PYBIND11_TOSTRING(x) PYBIND11_STRINGIFY(x)
@@ -438,7 +429,7 @@ enum class return_value_policy : uint8_t {
 
     /** Reference an existing object (i.e. do not create a new copy) and take
         ownership. Python will call the destructor and delete operator when the
-        object’s reference count reaches zero. Undefined behavior ensues when
+        object's reference count reaches zero. Undefined behavior ensues when
         the C++ side does the same.. */
     take_ownership,
 
@@ -454,7 +445,7 @@ enum class return_value_policy : uint8_t {
     move,
 
     /** Reference an existing object, but do not take ownership. The C++ side
-        is responsible for managing the object’s lifetime and deallocating it
+        is responsible for managing the object's lifetime and deallocating it
         when it is no longer used. Warning: undefined behavior will ensue when
         the C++ side deletes an object that is still referenced and used by
         Python. */
@@ -463,7 +454,7 @@ enum class return_value_policy : uint8_t {
     /** This policy only applies to methods and properties. It references the
         object without taking ownership similar to the above
         return_value_policy::reference policy. In contrast to that policy, the
-        function or property’s implicit this argument (called the parent) is
+        function or property's implicit this argument (called the parent) is
         considered to be the the owner of the return value (the child).
         pybind11 then couples the lifetime of the parent to the child via a
         reference relationship that ensures that the parent cannot be garbage

include/pybind11/detail/type_caster_base.h

@@ -439,10 +439,11 @@ PYBIND11_NOINLINE void instance::allocate_layout() {
                                         // instance_registered)
 
         // Allocate space for flags, values, and holders, and initialize it to 0 (flags and values,
-        // in particular, need to be 0).  Use Python's memory allocation functions: in Python 3.6
+        // in particular, need to be 0).  Use Python's memory allocation
-        // they default to using pymalloc, which is designed to be efficient for small allocations
+        // functions: Python is using pymalloc, which is designed to be
-        // like the one we're doing here; in earlier versions (and for larger allocations) they are
+        // efficient for small allocations like the one we're doing here;
-        // just wrappers around malloc.
+        // for larger allocations they are just wrappers around malloc.
+        // TODO: is this still true for pure Python 3.6?
         nonsimple.values_and_holders = (void **) PyMem_Calloc(space, sizeof(void *));
         if (!nonsimple.values_and_holders) {
             throw std::bad_alloc();
@@ -538,8 +539,6 @@ PYBIND11_NOINLINE handle get_object_handle(const void *ptr, const detail::type_i
 inline PyThreadState *get_thread_state_unchecked() {
 #if defined(PYPY_VERSION)
     return PyThreadState_GET();
-#elif PY_VERSION_HEX < 0x03050200
-    return (PyThreadState *) _PyThreadState_Current.value;
 #else
     return _PyThreadState_UncheckedGet();
 #endif

include/pybind11/pybind11.h

@@ -1213,7 +1213,7 @@ public:
         PyModule_AddObject(ptr(), name, obj.inc_ref().ptr() /* steals a reference */);
     }
 
-    using module_def = PyModuleDef;
+    using module_def = PyModuleDef; // TODO: Can this be removed (it was needed only for Python 2)?
 
     /** \rst
         Create a new top-level module that can be used as the main module of a C extension.
@@ -1242,7 +1242,7 @@ public:
         }
         // TODO: Should be reinterpret_steal for Python 3, but Python also steals it again when
         //       returned from PyInit_...
-        //       For Python 2, reinterpret_borrow is correct.
+        //       For Python 2, reinterpret_borrow was correct.
         return reinterpret_borrow<module_>(m);
     }
 };

include/pybind11/stl/filesystem.h

@@ -13,8 +13,7 @@
 #include <string>
 
 #ifdef __has_include
-#    if defined(PYBIND11_CPP17) && __has_include(<filesystem>) && \
+#    if defined(PYBIND11_CPP17) && __has_include(<filesystem>)
-      PY_VERSION_HEX >= 0x03060000
 #        include <filesystem>
 #        define PYBIND11_HAS_FILESYSTEM 1
 #    endif

noxfile.py

@@ -2,7 +2,7 @@ import nox
 
 nox.options.sessions = ["lint", "tests", "tests_packaging"]
 
-PYTHON_VERSIONS = ["3.5", "3.6", "3.7", "3.8", "3.9", "3.10", "3.11"]
+PYTHON_VERSIONS = ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11"]
 
 
 @nox.session(reuse_venv=True)

pybind11/__init__.py

@@ -1,7 +1,7 @@
 import sys
 
-if sys.version_info < (3, 5):
+if sys.version_info < (3, 6):
-    msg = "pybind11 does not support Python < 3.5. 2.9 was the last release supporting older Pythons."
+    msg = "pybind11 does not support Python < 3.6. 2.9 was the last release supporting Python 2.7 and 3.5."
     raise ImportError(msg)
 
 

pybind11/setup_helpers.py

@@ -200,7 +200,7 @@ class Pybind11Extension(_Extension):  # type: ignore[misc]
             current_macos = tuple(int(x) for x in platform.mac_ver()[0].split(".")[:2])
             desired_macos = (10, 9) if level < 17 else (10, 14)
             macos_string = ".".join(str(x) for x in min(current_macos, desired_macos))
-            macosx_min = "-mmacosx-version-min={}".format(macos_string)
+            macosx_min = f"-mmacosx-version-min={macos_string}"
             cflags += [macosx_min]
             ldflags += [macosx_min]
 
@@ -322,9 +322,9 @@ def intree_extensions(
 
     if not exts:
         msg = (
-            "path {path} is not a child of any of the directories listed "
+            f"path {path} is not a child of any of the directories listed "
-            "in 'package_dir' ({package_dir})"
+            f"in 'package_dir' ({package_dir})"
-        ).format(path=path, package_dir=package_dir)
+        )
         raise ValueError(msg)
 
     return exts
@@ -419,7 +419,7 @@ class ParallelCompile:
         self.default = default
         self.max = max
         self.needs_recompile = needs_recompile
-        self._old = []  # type: List[CCompilerMethod]
+        self._old: List[CCompilerMethod] = []
 
     def function(self) -> CCompilerMethod:
         """

setup.cfg

@@ -14,7 +14,6 @@ classifiers =
     Topic :: Utilities
     Programming Language :: C++
     Programming Language :: Python :: 3 :: Only
-    Programming Language :: Python :: 3.5
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
@@ -38,7 +37,7 @@ project_urls =
     Chat = https://gitter.im/pybind/Lobby
 
 [options]
-python_requires = >=3.5
+python_requires = >=3.6
 zip_safe = False
 
 
@@ -46,14 +45,5 @@ zip_safe = False
 max-line-length = 120
 show_source = True
 exclude = .git, __pycache__, build, dist, docs, tools, venv
-ignore =
+extend-ignore = E203, E722, B950
-    # required for pretty matrix formatting: multiple spaces after `,` and `[`
+select = C,E,F,N,W,B,B9
-    E201, E241, W504,
-    # camelcase 'cPickle' imported as lowercase 'pickle'
-    N813
-    # Black conflict
-    W503, E203
-
-
-[tool:pytest]
-timeout = 300

setup.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # Setup script for PyPI; use CMakeFile.txt to build extension modules
 
@@ -41,12 +41,10 @@ def build_expected_version_hex(matches: Dict[str, str]) -> str:
                     serial = int(level_serial[len(level) :])
                     break
     if serial is None:
-        msg = 'Invalid PYBIND11_VERSION_PATCH: "{}"'.format(patch_level_serial)
+        msg = f'Invalid PYBIND11_VERSION_PATCH: "{patch_level_serial}"'
         raise RuntimeError(msg)
-    version_hex_str = "{:02x}{:02x}{:02x}{}{:x}".format(
+    version_hex_str = f"{major:02x}{minor:02x}{patch:02x}{level[:1]}{serial:x}"
-        major, minor, patch, level[:1], serial
+    return f"0x{version_hex_str.upper()}"
-    )
-    return "0x{}".format(version_hex_str.upper())
 
 
 # PYBIND11_GLOBAL_SDIST will build a different sdist, with the python-headers
@@ -66,7 +64,7 @@ to_src = (
 
 
 # Read the listed version
-loc = {}  # type: Dict[str, str]
+loc: Dict[str, str] = {}
 code = compile(VERSION_FILE.read_text(encoding="utf-8"), "pybind11/_version.py", "exec")
 exec(code, loc)
 version = loc["__version__"]
@@ -75,17 +73,13 @@ version = loc["__version__"]
 matches = dict(VERSION_REGEX.findall(COMMON_FILE.read_text(encoding="utf8")))
 cpp_version = "{MAJOR}.{MINOR}.{PATCH}".format(**matches)
 if version != cpp_version:
-    msg = "Python version {} does not match C++ version {}!".format(
+    msg = f"Python version {version} does not match C++ version {cpp_version}!"
-        version, cpp_version
-    )
     raise RuntimeError(msg)
 
 version_hex = matches.get("HEX", "MISSING")
 exp_version_hex = build_expected_version_hex(matches)
 if version_hex != exp_version_hex:
-    msg = "PYBIND11_VERSION_HEX {} does not match expected value {}!".format(
+    msg = f"PYBIND11_VERSION_HEX {version_hex} does not match expected value {exp_version_hex}!"
-        version_hex, exp_version_hex
-    )
     raise RuntimeError(msg)
 
 

tests/extra_python_package/test_files.py

@@ -145,9 +145,9 @@ def test_build_sdist(monkeypatch, tmpdir):
             contents = f.read().decode("utf8")
         assert 'set(pybind11_INCLUDE_DIR "${PACKAGE_PREFIX_DIR}/include")' in contents
 
-    files = {"pybind11/{}".format(n) for n in all_files}
+    files = {f"pybind11/{n}" for n in all_files}
     files |= sdist_files
-    files |= {"pybind11{}".format(n) for n in local_sdist_files}
+    files |= {f"pybind11{n}" for n in local_sdist_files}
     files.add("pybind11.egg-info/entry_points.txt")
     files.add("pybind11.egg-info/requires.txt")
     assert simpler == files
@@ -200,9 +200,9 @@ def test_build_global_dist(monkeypatch, tmpdir):
         ) as f:
             pyproject_toml = f.read()
 
-    files = {"pybind11/{}".format(n) for n in all_files}
+    files = {f"pybind11/{n}" for n in all_files}
     files |= sdist_files
-    files |= {"pybind11_global{}".format(n) for n in local_sdist_files}
+    files |= {f"pybind11_global{n}" for n in local_sdist_files}
     assert simpler == files
 
     with open(os.path.join(MAIN_DIR, "tools", "setup_global.py.in"), "rb") as f:
@@ -227,7 +227,7 @@ def tests_build_wheel(monkeypatch, tmpdir):
 
     (wheel,) = tmpdir.visit("*.whl")
 
-    files = {"pybind11/{}".format(n) for n in all_files}
+    files = {f"pybind11/{n}" for n in all_files}
     files |= {
         "dist-info/LICENSE",
         "dist-info/METADATA",
@@ -241,9 +241,7 @@ def tests_build_wheel(monkeypatch, tmpdir):
         names = z.namelist()
 
     trimmed = {n for n in names if "dist-info" not in n}
-    trimmed |= {
+    trimmed |= {f"dist-info/{n.split('/', 1)[-1]}" for n in names if "dist-info" in n}
-        "dist-info/{}".format(n.split("/", 1)[-1]) for n in names if "dist-info" in n
-    }
     assert files == trimmed
 
 
@@ -257,8 +255,8 @@ def tests_build_global_wheel(monkeypatch, tmpdir):
 
     (wheel,) = tmpdir.visit("*.whl")
 
-    files = {"data/data/{}".format(n) for n in src_files}
+    files = {f"data/data/{n}" for n in src_files}
-    files |= {"data/headers/{}".format(n[8:]) for n in headers}
+    files |= {f"data/headers/{n[8:]}" for n in headers}
     files |= {
         "dist-info/LICENSE",
         "dist-info/METADATA",

tests/extra_setuptools/test_setuphelper.py

@@ -18,7 +18,7 @@ def test_simple_setup_py(monkeypatch, tmpdir, parallel, std):
 
     (tmpdir / "setup.py").write_text(
         dedent(
-            """\
+            f"""\
             import sys
             sys.path.append({MAIN_DIR!r})
 
@@ -51,7 +51,7 @@ def test_simple_setup_py(monkeypatch, tmpdir, parallel, std):
                 ext_modules=ext_modules,
             )
             """
-        ).format(MAIN_DIR=MAIN_DIR, std=std, parallel=parallel),
+        ),
         encoding="ascii",
     )
 

tests/pytest.ini

@@ -1,12 +1,15 @@
 [pytest]
-minversion = 3.1
+minversion = 3.10
 norecursedirs = test_* extra_*
 xfail_strict = True
 addopts =
-    # show summary of skipped tests
+    # show summary of tests
-    -rs
+    -ra
     # capture only Python print and C++ py::print, but not C output (low-level Python errors)
     --capture=sys
+    # Show local info when a failure occurs
+    --showlocals
+log_cli_level = info
 filterwarnings =
     # make warnings into errors but ignore certain third-party extension issues
     error

tests/requirements.txt

@@ -1,12 +1,8 @@
-numpy==1.16.6; python_version<"3.6" and sys_platform!="win32" and platform_python_implementation!="PyPy"
+numpy==1.21.5; platform_python_implementation=="PyPy" and sys_platform=="linux" and python_version=="3.7"
-numpy==1.19.0; platform_python_implementation=="PyPy" and sys_platform=="linux" and python_version=="3.6"
-numpy==1.20.0; platform_python_implementation=="PyPy" and sys_platform=="linux" and python_version=="3.7"
 numpy==1.19.3; platform_python_implementation!="PyPy" and python_version=="3.6"
-numpy==1.21.3; platform_python_implementation!="PyPy" and python_version>="3.7" and python_version<"3.11"
+numpy==1.21.5; platform_python_implementation!="PyPy" and python_version>="3.7" and python_version<"3.10"
-py @ git+https://github.com/pytest-dev/py; python_version>="3.11"
+numpy==1.22.2; platform_python_implementation!="PyPy" and python_version>="3.10" and python_version<"3.11"
-pytest==4.6.9; python_version<"3.5"
+pytest==7.0.0
-pytest==6.1.2; python_version=="3.5"
-pytest==6.2.4; python_version>="3.6"
 pytest-timeout
-scipy==1.2.3; platform_python_implementation!="PyPy" and python_version<"3.6"
+scipy==1.5.4; platform_python_implementation!="PyPy" and python_version<"3.10"
-scipy==1.5.4; platform_python_implementation!="PyPy" and python_version>="3.6" and python_version<"3.10"
+scipy==1.8.0; platform_python_implementation!="PyPy" and python_version=="3.10"

tests/test_builtin_casters.py

@@ -50,7 +50,7 @@ def test_single_char_arguments():
     """Tests failures for passing invalid inputs to char-accepting functions"""
 
     def toobig_message(r):
-        return "Character code point not in range({:#x})".format(r)
+        return f"Character code point not in range({r:#x})"
 
     toolong_message = "Expected a character, but multi-character string found"
 

tests/test_callbacks.py

@@ -17,7 +17,7 @@ def test_callbacks():
         return "func2", a, b, c, d
 
     def func3(a):
-        return "func3({})".format(a)
+        return f"func3({a})"
 
     assert m.test_callback1(func1) == "func1"
     assert m.test_callback2(func2) == ("func2", "Hello", "x", True, 5)
@@ -188,14 +188,8 @@ def test_callback_num_times():
         if not rep:
             print()
         print(
-            "callback_num_times: {:d} million / {:.3f} seconds = {:.3f} million / second".format(
+            f"callback_num_times: {num_millions:d} million / {td:.3f} seconds = {rate:.3f} million / second"
-                num_millions, td, rate
-            )
         )
     if len(rates) > 1:
         print("Min    Mean   Max")
-        print(
+        print(f"{min(rates):6.3f} {sum(rates) / len(rates):6.3f} {max(rates):6.3f}")
-            "{:6.3f} {:6.3f} {:6.3f}".format(
-                min(rates), sum(rates) / len(rates), max(rates)
-            )
-        )

tests/test_chrono.py

@@ -100,7 +100,7 @@ SKIP_TZ_ENV_ON_WIN = pytest.mark.skipif(
 )
 def test_chrono_system_clock_roundtrip_time(time1, tz, monkeypatch):
     if tz is not None:
-        monkeypatch.setenv("TZ", "/usr/share/zoneinfo/{}".format(tz))
+        monkeypatch.setenv("TZ", f"/usr/share/zoneinfo/{tz}")
 
     # Roundtrip the time
     datetime2 = m.test_chrono2(time1)

tests/test_cmake_build/test.py

@@ -5,4 +5,4 @@ import test_cmake_build
 assert isinstance(__file__, str)  # Test this is properly set
 
 assert test_cmake_build.add(1, 2) == 3
-print("{} imports, runs, and adds: 1 + 2 = 3".format(sys.argv[1]))
+print(f"{sys.argv[1]} imports, runs, and adds: 1 + 2 = 3")

tests/test_eigen.py

@@ -221,9 +221,7 @@ def test_nonunit_stride_to_python():
     assert np.all(m.diagonal(ref) == ref.diagonal())
     assert np.all(m.diagonal_1(ref) == ref.diagonal(1))
     for i in range(-5, 7):
-        assert np.all(
+        assert np.all(m.diagonal_n(ref, i) == ref.diagonal(i)), f"m.diagonal_n({i})"
-            m.diagonal_n(ref, i) == ref.diagonal(i)
-        ), "m.diagonal_n({})".format(i)
 
     assert np.all(m.block(ref, 2, 1, 3, 3) == ref[2:5, 1:4])
     assert np.all(m.block(ref, 1, 4, 4, 2) == ref[1:, 4:])
@@ -236,7 +234,7 @@ def test_eigen_ref_to_python():
         mymat = chol(np.array([[1.0, 2, 4], [2, 13, 23], [4, 23, 77]]))
         assert np.all(
             mymat == np.array([[1, 0, 0], [2, 3, 0], [4, 5, 6]])
-        ), "cholesky{}".format(i)
+        ), f"cholesky{i}"
 
 
 def assign_both(a1, a2, r, c, v):

tests/test_exceptions.py

@@ -88,7 +88,7 @@ def test_python_call_in_catch():
 def ignore_pytest_unraisable_warning(f):
     unraisable = "PytestUnraisableExceptionWarning"
     if hasattr(pytest, unraisable):  # Python >= 3.8 and pytest >= 6
-        dec = pytest.mark.filterwarnings("ignore::pytest.{}".format(unraisable))
+        dec = pytest.mark.filterwarnings(f"ignore::pytest.{unraisable}")
         return dec(f)
     else:
         return f

tests/test_numpy_array.py

@@ -18,9 +18,7 @@ def test_dtypes():
         assert check.numpy == check.pybind11, check
         if check.numpy.num != check.pybind11.num:
             print(
-                "NOTE: typenum mismatch for {}: {} != {}".format(
+                f"NOTE: typenum mismatch for {check}: {check.numpy.num} != {check.pybind11.num}"
-                    check, check.numpy.num, check.pybind11.num
-                )
             )
 
 
@@ -116,9 +114,7 @@ def test_at_fail(arr, dim):
     for func in m.at_t, m.mutate_at_t:
         with pytest.raises(IndexError) as excinfo:
             func(arr, *([0] * dim))
-        assert str(excinfo.value) == "index dimension mismatch: {} (ndim = 2)".format(
+        assert str(excinfo.value) == f"index dimension mismatch: {dim} (ndim = 2)"
-            dim
-        )
 
 
 def test_at(arr):
@@ -192,8 +188,6 @@ def test_make_empty_shaped_array():
 
 def test_wrap():
     def assert_references(a, b, base=None):
-        from distutils.version import LooseVersion
-
         if base is None:
             base = a
         assert a is not b
@@ -204,7 +198,8 @@ def test_wrap():
         assert a.flags.f_contiguous == b.flags.f_contiguous
         assert a.flags.writeable == b.flags.writeable
         assert a.flags.aligned == b.flags.aligned
-        if LooseVersion(np.__version__) >= LooseVersion("1.14.0"):
+        # 1.13 supported Python 3.6
+        if tuple(int(x) for x in np.__version__.split(".")[:2]) >= (1, 14):
             assert a.flags.writebackifcopy == b.flags.writebackifcopy
         else:
             assert a.flags.updateifcopy == b.flags.updateifcopy

tests/test_numpy_dtypes.py

@@ -14,7 +14,7 @@ def simple_dtype():
     return np.dtype(
         {
             "names": ["bool_", "uint_", "float_", "ldbl_"],
-            "formats": ["?", "u4", "f4", "f{}".format(ld.itemsize)],
+            "formats": ["?", "u4", "f4", f"f{ld.itemsize}"],
             "offsets": [0, 4, 8, (16 if ld.alignment > 4 else 12)],
         }
     )
@@ -125,7 +125,7 @@ def test_dtype(simple_dtype):
     assert [x.replace(" ", "") for x in m.print_dtypes()] == [
         simple_dtype_fmt(),
         packed_dtype_fmt(),
-        "[('a',{}),('b',{})]".format(simple_dtype_fmt(), packed_dtype_fmt()),
+        f"[('a',{simple_dtype_fmt()}),('b',{packed_dtype_fmt()})]",
         partial_dtype_fmt(),
         partial_nested_fmt(),
         "[('a','S3'),('b','S3')]",

tests/test_opaque_types.py

@@ -12,7 +12,7 @@ def test_string_list():
     assert lst.back() == "Element 2"
 
     for i, k in enumerate(lst, start=1):
-        assert k == "Element {}".format(i)
+        assert k == f"Element {i}"
     lst.pop_back()
     assert m.print_opaque_list(lst) == "Opaque list: [Element 1]"
 

tests/test_pytypes.py

@@ -305,8 +305,8 @@ def test_non_converting_constructors():
         for move in [True, False]:
             with pytest.raises(TypeError) as excinfo:
                 m.nonconverting_constructor(t, v, move)
-            expected_error = "Object of type '{}' is not an instance of '{}'".format(
+            expected_error = (
-                type(v).__name__, t
+                f"Object of type '{type(v).__name__}' is not an instance of '{t}'"
             )
             assert str(excinfo.value) == expected_error
 

tests/test_sequences_and_iterators.py

@@ -1,20 +1,10 @@
 import pytest
+from pytest import approx
 
 from pybind11_tests import ConstructorStats
 from pybind11_tests import sequences_and_iterators as m
 
 
-def isclose(a, b, rel_tol=1e-05, abs_tol=0.0):
-    """Like math.isclose() from Python 3.5"""
-    return abs(a - b) <= max(rel_tol * max(abs(a), abs(b)), abs_tol)
-
-
-def allclose(a_list, b_list, rel_tol=1e-05, abs_tol=0.0):
-    return all(
-        isclose(a, b, rel_tol=rel_tol, abs_tol=abs_tol) for a, b in zip(a_list, b_list)
-    )
-
-
 def test_slice_constructors():
     assert m.make_forward_slice_size_t() == slice(0, -1, 1)
     assert m.make_reversed_slice_object() == slice(None, None, -1)
@@ -117,7 +107,8 @@ def test_sequence():
     assert 12.34 not in s
     s[0], s[3] = 12.34, 56.78
     assert 12.34 in s
-    assert isclose(s[0], 12.34) and isclose(s[3], 56.78)
+    assert s[0] == approx(12.34, rel=1e-05)
+    assert s[3] == approx(56.78, rel=1e-05)
 
     rev = reversed(s)
     assert cstats.values() == ["of size", "5"]
@@ -132,14 +123,14 @@ def test_sequence():
     assert cstats.values() == ["of size", "0"]
 
     expected = [0, 56.78, 0, 0, 12.34]
-    assert allclose(rev, expected)
+    assert rev == approx(expected, rel=1e-05)
-    assert allclose(rev2, expected)
+    assert rev2 == approx(expected, rel=1e-05)
     assert rev == rev2
 
     rev[0::2] = m.Sequence([2.0, 2.0, 2.0])
     assert cstats.values() == ["of size", "3", "from std::vector"]
 
-    assert allclose(rev, [2, 56.78, 2, 0, 2])
+    assert rev == approx([2, 56.78, 2, 0, 2], rel=1e-05)
 
     assert cstats.alive() == 4
     del it

tests/test_smart_ptr.py

@@ -15,7 +15,7 @@ def test_smart_ptr(capture):
             m.print_object_2(o)
             m.print_object_3(o)
             m.print_object_4(o)
-        assert capture == "MyObject1[{i}]\n".format(i=i) * 4
+        assert capture == f"MyObject1[{i}]\n" * 4
 
     for i, o in enumerate(
         [m.make_myobject1_1(), m.make_myobject1_2(), m.MyObject1(6), 7], start=4
@@ -33,13 +33,11 @@ def test_smart_ptr(capture):
             m.print_myobject1_4(o)
 
         times = 4 if isinstance(o, int) else 8
-        assert capture == "MyObject1[{i}]\n".format(i=i) * times
+        assert capture == f"MyObject1[{i}]\n" * times
 
     cstats = ConstructorStats.get(m.MyObject1)
     assert cstats.alive() == 0
-    expected_values = ["MyObject1[{}]".format(i) for i in range(1, 7)] + [
+    expected_values = [f"MyObject1[{i}]" for i in range(1, 7)] + ["MyObject1[7]"] * 4
-        "MyObject1[7]"
-    ] * 4
     assert cstats.values() == expected_values
     assert cstats.default_constructions == 0
     assert cstats.copy_constructions == 0
@@ -57,7 +55,7 @@ def test_smart_ptr(capture):
             m.print_myobject2_2(o)
             m.print_myobject2_3(o)
             m.print_myobject2_4(o)
-        assert capture == "MyObject2[{i}]\n".format(i=i) * 4
+        assert capture == f"MyObject2[{i}]\n" * 4
 
     cstats = ConstructorStats.get(m.MyObject2)
     assert cstats.alive() == 1
@@ -80,7 +78,7 @@ def test_smart_ptr(capture):
             m.print_myobject3_2(o)
             m.print_myobject3_3(o)
             m.print_myobject3_4(o)
-        assert capture == "MyObject3[{i}]\n".format(i=i) * 4
+        assert capture == f"MyObject3[{i}]\n" * 4
 
     cstats = ConstructorStats.get(m.MyObject3)
     assert cstats.alive() == 1

tests/test_virtual_functions.py

@@ -13,7 +13,7 @@ def test_override(capture, msg):
             self.data = "Hello world"
 
         def run(self, value):
-            print("ExtendedExampleVirt::run(%i), calling parent.." % value)
+            print(f"ExtendedExampleVirt::run({value}), calling parent..")
             return super().run(value + 1)
 
         def run_bool(self):
@@ -24,7 +24,7 @@ def test_override(capture, msg):
             return "override1"
 
         def pure_virtual(self):
-            print("ExtendedExampleVirt::pure_virtual(): %s" % self.data)
+            print(f"ExtendedExampleVirt::pure_virtual(): {self.data}")
 
     class ExtendedExampleVirt2(ExtendedExampleVirt):
         def __init__(self, state):

tools/FindPythonLibsNew.cmake

@@ -92,7 +92,7 @@ endif()
 
 # Use the Python interpreter to find the libs.
 if(NOT PythonLibsNew_FIND_VERSION)
-  set(PythonLibsNew_FIND_VERSION "3.5")
+  set(PythonLibsNew_FIND_VERSION "3.6")
 endif()
 
 find_package(PythonInterp ${PythonLibsNew_FIND_VERSION} ${_pythonlibs_required}

tools/libsize.py

@@ -13,7 +13,7 @@ lib = sys.argv[1]
 save = sys.argv[2]
 
 if not os.path.exists(lib):
-    sys.exit("Error: requested file ({}) does not exist".format(lib))
+    sys.exit(f"Error: requested file ({lib}) does not exist")
 
 libsize = os.path.getsize(lib)
 
@@ -28,7 +28,7 @@ if os.path.exists(save):
         if change == 0:
             print(" (no change)")
         else:
-            print(" (change of {:+} bytes = {:+.2%})".format(change, change / oldsize))
+            print(f" (change of {change:+} bytes = {change / oldsize:+.2%})")
 else:
     print()
 

tools/pybind11Config.cmake.in

@@ -193,7 +193,7 @@ Using ``find_package`` with version info is not recommended except for release v
 .. code-block:: cmake
 
   find_package(pybind11 CONFIG)
-  find_package(pybind11 2.0 EXACT CONFIG REQUIRED)
+  find_package(pybind11 2.9 EXACT CONFIG REQUIRED)
 
 #]=============================================================================]
 @PACKAGE_INIT@

tools/pybind11NewTools.cmake

@@ -32,7 +32,7 @@ if(NOT Python_FOUND AND NOT Python3_FOUND)
     set(Python_ROOT_DIR "$ENV{pythonLocation}")
   endif()
 
-  find_package(Python 3.5 REQUIRED COMPONENTS Interpreter Development ${_pybind11_quiet})
+  find_package(Python 3.6 REQUIRED COMPONENTS Interpreter Development ${_pybind11_quiet})
 
   # If we are in submodule mode, export the Python targets to global targets.
   # If this behavior is not desired, FindPython _before_ pybind11.

tools/pybind11Tools.cmake

@@ -43,7 +43,7 @@ endif()
 
 # A user can set versions manually too
 set(Python_ADDITIONAL_VERSIONS
-    "3.11;3.10;3.9;3.8;3.7;3.6;3.5"
+    "3.11;3.10;3.9;3.8;3.7;3.6"
     CACHE INTERNAL "")
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}")

tools/setup_global.py.in

@@ -1,5 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 
 # Setup script for pybind11-global (in the sdist or in tools/setup_global.py in the repository)
 # This package is targeted for easy use from CMake.

tools/setup_main.py.in

@@ -1,5 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 
 # Setup script (in the sdist or in tools/setup_main.py in the repository)