[Build] Remove official support for CY22

Closes OpenAssetIO#1389. Closes OpenAssetIO#1352.

VFX Reference Platform CY22 is rather old now, especially to use as a
default, and removing support has additional advantages:

* We no longer need to worry about switching the libstdc++ ABI between
  old and new. E.g. previously we were using the old ABI even for Python
  3.10+ wheel builds, which was wrong.
* We no longer need to use the backport of `importlib_metadata`, since
  the API is stable as of Python 3.10 (CY23).

So remove Python 3.9 support, including no longer building/deploying
wheels.

Hence bump the `cibuildwheel` Docker image to `manylinux_2_28` for all
Python wheels, and use the new libstdc++ ABI for Conan packages. This
then means the libstdc++ ABI and glibc version matches for at least CY23
through CY24 (and likely CY25 too).

Also remove `importlib_metadata` dependency, now that it's no longer
required since Python 3.10+ has a stable API.

Signed-off-by: David Feltell <[email protected]>

.github/workflows/build-wheels.yml

@@ -34,7 +34,7 @@ jobs:
           # These are the platform build strings provided to
           # cibuildwheel, with wildcarding. See
           # https://cibuildwheel.readthedocs.io/en/stable/options/#build-skip
-        python-build: ['cp39*64', 'cp310*64', 'cp311*64']
+        python-build: ['cp310*64', 'cp311*64']
     defaults:
       run:
         # Annoyingly required here since `matrix` isn't available in the
@@ -68,10 +68,12 @@ jobs:
           # deploy on that platform.
           CIBW_BUILD: ${{ matrix.python-build }}
           CIBW_SKIP: '*musllinux* *arm64*'
-          CIBW_MANYLINUX_X86_64_IMAGE: manylinux2014
+          # manylinux_2_28 is based on AlmaLinux 8, which uses glibc
+          # 2.28 and new libstdc++ ABI.
+          CIBW_MANYLINUX_X86_64_IMAGE: manylinux_2_28
           PIP_VERBOSE: 1
-          # Required as we make use of c++17 features
-          MACOSX_DEPLOYMENT_TARGET: 10.15
+          # VFX Reference Platform CY23-CY24
+          MACOSX_DEPLOYMENT_TARGET: 11
           # Ensure .pyi stub tests won't be skipped
           OPENASSETIO_TEST_ENABLE_PYTHON_STUBGEN: 1
 

CMakeLists.txt

@@ -13,8 +13,8 @@ cmake_minimum_required(VERSION 3.27)
 # Additional include directories for CMake utils.
 list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_LIST_DIR}/cmake)
 
-# Minimum required for the C++17 features used.
-set(CMAKE_OSX_DEPLOYMENT_TARGET 10.15)
+# VFX Reference Platform CY23-CY24
+set(CMAKE_OSX_DEPLOYMENT_TARGET 11)
 
 # Forbid in-source builds.
 if (${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_BINARY_DIR})

RELEASE_NOTES.md

@@ -11,9 +11,10 @@ section for more details._
 
 ### Breaking changes
 
-- Removed official support for Python 3.7. The minimum supported Python
-  version is now Python 3.9.
+- Removed official support for Python 3.7 and 3.9. The minimum supported
+  Python version is now Python 3.10. This includes PyPI packages.
   [#1365](https://github.com/OpenAssetIO/OpenAssetIO/pull/1365)
+  [#1389](https://github.com/OpenAssetIO/OpenAssetIO/pull/1389)
 
 - Removed deprecated type aliases `openassetio.TraitsData`,
   `openassetio.BatchElementError`
@@ -81,13 +82,21 @@ section for more details._
   `openassetio.test.manager` API Compliance test harness, to aid in
   IDE code completion when writing test cases for manager plugins.
 
+- `importlib_metadata` is no longer a dependency for Python
+  manager plugins to make use of Python entry point hooks.
+  [#1389](https://github.com/OpenAssetIO/OpenAssetIO/issues/1389)
+
 ### Bug fixes
 
 - Modified OpenAssetIO Python distributions (e.g. installed with `pip
   install`) to allow C++ plugins to load. OpenAssetIO is now bundled as
   multiple shared libraries, allowing external libraries to link.
   [#1340](https://github.com/OpenAssetIO/OpenAssetIO/issues/1340)
 
+- Fixed Python wheel builds to use the new libstdc++ ABI, reflecting
+  their associated VFX Reference Platform version.
+  [#1352](https://github.com/OpenAssetIO/OpenAssetIO/issues/1352)
+
 - Fixed the (Python-only) `terminology.Mapper` class such that its
   terminology dict can be updated by the manager.
   [#1356](https://github.com/OpenAssetIO/OpenAssetIO/pull/1356)

doc/BUILDING.md

@@ -20,7 +20,7 @@ We assume the following system packages are installed
 
 - CMake 3.27+
 - C++17 or later compliant compiler
-(GCC 9.3+ / MSVC 16.9+ / macOS 10.15+)
+(GCC 11.2+ / MSVC 17.4+ / macOS 11+)
 
 For linting and other build verification options, we assume the
 following packages are installed:
@@ -34,7 +34,7 @@ following packages are installed:
 Binary builds additionally require the following packages to be
 available.
 
-- [Python 3.9+](https://www.python.org/) (development install)
+- [Python 3.10+](https://www.python.org/) (development install)
 - [pybind11](https://pybind11.readthedocs.io/en/stable/) 2.8.1+
 - [toml++](https://marzer.github.io/tomlplusplus/) 3.2.0+
 - [fmt](https://github.com/fmtlib/fmt) 9.1.0

doc/contributing/CODING_STANDARDS.md

@@ -55,7 +55,7 @@ disambiguating fixtures from tests.
 ### Python
 
 Python code should be written using only features included in Python
-3.9.
+3.10.
 
 Where feasible, Python unit test cases should use a class for each unit,
 where the methods of the test class are the test cases for that unit. In

doc/doxygen/src/Configuration.dox

@@ -207,9 +207,6 @@
  *   version as the one used to install via `pip`.
  * - Check that the appropriate directory is on `sys.path` in the
  *   host's interpreter.
- * - Check that `importlib_metadata` is available to the host
- *   interpreter (a message will be logged during startup if this is
- *   missing).
  *
  * @subsection manual_plugins_missing Manually installed plugins not being found
  *

resources/build/bootstrap-cibuildwheel-manylinux-2014.sh → resources/build/bootstrap-cibuildwheel-manylinux.sh

@@ -14,13 +14,12 @@ pip3 install -r "resources/build/requirements.txt"
 # Use explicit predictable conan root path, where packages are cached.
 export CONAN_USER_HOME="$HOME/conan"
 
-# Create default conan profile so we can configure it before instlibXcomposite-develall.
+# Create default conan profile so we can configure it before install.
 # Use --force so that if it already exists we don't error out.
 conan profile new default --detect --force
-# Use old C++11 ABI as per VFX Reference Platform CY2022. Not strictly
-# necessary as this is the default for conan, but we can't be certain
-# it'll remain the default in future.
-conan profile update settings.compiler.libcxx=libstdc++ default
+# Use new/non-deprecated C++11 ABI to match VFX Reference Platform
+# CY23+.
+conan profile update settings.compiler.libcxx=libstdc++11 default
 # If we need to pin a package to a specific Conan recipe revision, then
 # we need to explicitly opt-in to this functionality.
 conan config set general.revisions_enabled=True

src/openassetio-python/package/openassetio/pluginSystem/PythonPluginSystem.py

@@ -19,6 +19,7 @@
 """
 
 import os.path
+import importlib.metadata
 import importlib.util
 import hashlib
 import sys
@@ -113,30 +114,17 @@ def scan_entry_points(self, entryPointName):
         the first plugin with any given identifier will be registered.
 
         @param entryPointName `str` The entry point name to search for
-        (see: importlib_metadata.entry_points group).
+        (see: importlib.metadata.entry_points group).
 
         @returns True if entry point discovery is possible, False if
-        there was a problem loading importlib_metadata.
+        there was a problem loading importlib.metadata.
         """
 
-        # We opt to use the backport implementation of modern importlib
-        # since the API changes from 3.9 to 3.10.
-        # Pip installs should have this module available, but other methods may not,
-        # so be tolerant of it being missing.
-        try:
-            import importlib_metadata  # pylint: disable=import-outside-toplevel
-        except ImportError:
-            self.__logger.warning(
-                "PythonPluginSystem: Can not load entry point plugins as the importlib_metadata "
-                "package is unavailable."
-            )
-            return False
-
         self.__logger.debug(
             f"PythonPluginSystem: Searching packages for '{entryPointName}' entry points."
         )
 
-        for entryPoint in importlib_metadata.entry_points(group=entryPointName):
+        for entryPoint in importlib.metadata.entry_points(group=entryPointName):
             self.__logger.debug(f"PythonPluginSystem: Found entry point in {entryPoint.name}")
             try:
                 module = entryPoint.load()

src/openassetio-python/pyproject.toml

@@ -14,10 +14,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "openassetio"
 version = "1.0.0b2.rev2"
-requires-python = ">=3.9"
-dependencies = [
-    "importlib_metadata >= 3.6"
-]
+requires-python = ">=3.10"
 
 authors = [
     { name = "Contributors to the OpenAssetIO project", email = "[email protected]" }
@@ -37,7 +34,6 @@ classifiers = [
     "Operating System :: Microsoft :: Windows",
     "Operating System :: POSIX :: Linux",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Topic :: Software Development :: Libraries :: Python Modules",
@@ -144,5 +140,5 @@ environment-pass = ["PIP_VERBOSE", "OPENASSETIO_TEST_ENABLE_PYTHON_STUBGEN"]
 
 [tool.cibuildwheel.linux]
 # Linux runs in a docker container, with the project at top level
-before-build = "resources/build/bootstrap-cibuildwheel-manylinux-2014.sh"
+before-build = "resources/build/bootstrap-cibuildwheel-manylinux.sh"
 environment = { CMAKE_TOOLCHAIN_FILE=".conan/conan_paths.cmake" }

src/openassetio-python/tests/CMakeLists.txt

@@ -47,13 +47,6 @@ endif ()
 #-----------------------------------------------------------------------
 # Test dependencies.
 
-# Install openassetio-specific dependencies that allow us to
-# extend PYTHONPATH without needing to pip install to run tests.
-openassetio_add_python_environment_dependency(
-    openassetio.internal.python.install-deps
-    "${PROJECT_SOURCE_DIR}/src/openassetio-python/requirements.txt"
-)
-
 # Install test-specific dependencies (e.g. pytest).
 openassetio_add_python_environment_dependency(
     openassetio.internal.pytest.install-deps

src/openassetio-python/tests/package/pluginSystem/resources/broken/src/missing_plugin/pyproject.toml

@@ -10,7 +10,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "missing-plugin"
 version = "0.0.0"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 
 description = """\
     A test OpenAssetIO Manager plugin that is missing the top-level

src/openassetio-python/tests/package/pluginSystem/resources/broken/src/raises_exception/pyproject.toml

@@ -10,7 +10,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "raises-exception"
 version = "0.0.0"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 
 description = """\
     A test OpenAssetIO Manager plugin that raises an exception during inmport.

src/openassetio-python/tests/package/pluginSystem/resources/entryPoint/src/pyproject.toml

@@ -10,7 +10,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "packaged-plugin"
 version = "0.0.0"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 
 description = """\
     A test OpenAssetIO Manager plugin that can be pip installed and \

src/openassetio-python/tests/package/pluginSystem/test_pythonpluginsystem.py

@@ -175,22 +175,6 @@ def test_when_entry_point_package_installed_then_loaded_and_true_returned(
         assert a_plugin_system.scan_entry_points(PLUGIN_ENTRY_POINT_GROUP) is True
         assert a_plugin_system.identifiers() == [entry_point_plugin_identifier]
 
-    def test_when_importlib_metadata_missing_then_a_warning_is_loggeed_and_false_returned(
-        self, mock_logger, monkeypatch
-    ):
-        # Remove any previously imported versions
-        sys.modules.pop("importlib_metadata", None)
-        monkeypatch.setattr(sys, "path", [])
-
-        plugin_system = PythonPluginSystem(mock_logger)
-        assert plugin_system.scan_entry_points("some.entrypoint") is False
-
-        mock_logger.mock.log.assert_called_once_with(
-            mock_logger.Severity.kWarning,
-            "PythonPluginSystem: Can not load entry point plugins as the importlib_metadata "
-            "package is unavailable.",
-        )
-
     def test_when_plugins_broken_then_skipped_with_expected_errors(
         self, broken_python_plugins_path, mock_logger, monkeypatch
     ):

src/openassetio-python/tests/test_cmake.py

@@ -18,18 +18,11 @@
 """
 # pylint: disable=missing-function-docstring,invalid-name
 import os
+from importlib import metadata
 
 import pytest
 
 
-try:
-    from importlib import metadata
-
-    # pylint: disable=bare-except
-except:
-    import importlib_metadata as metadata
-
-
 @pytest.mark.skipif(
     os.environ.get("OPENASSETIO_CMAKE_PACKAGE_VERSION") is None, reason="CMake package only"
 )