Merge pull request #2249 from rmartin16/version-dependent-imports

Clarify imports that are dependent on the version of Python

.github/workflows/ci.yml

@@ -193,7 +193,7 @@ jobs:
 
  - backend: android
  runs-on: ubuntu-latest
- briefcase-run-args: " -d '{\"avd\":\"beePhone\"}' --Xemulator=-no-window --Xemulator=-no-snapshot --Xemulator=-no-audio --Xemulator=-no-boot-anim --shutdown-on-exit"
+ briefcase-run-args: " -d '{\"avd\":\"beePhone\",\"skin\":\"pixel_3a\"}' --Xemulator=-no-window --Xemulator=-no-snapshot --Xemulator=-no-audio --Xemulator=-no-boot-anim --shutdown-on-exit"
  pre-command: |
  # check if virtualization is supported...
  sudo apt install -qq --no-install-recommends cpu-checker coreutils && echo "CPUs=$(nproc --all)" && kvm-ok

.pre-commit-config.yaml

@@ -9,16 +9,15 @@ repos:
  - id: check-docstring-first
  - id: end-of-file-fixer
  - id: trailing-whitespace
- - repo: https://github.com/PyCQA/isort
- rev: 5.12.0
- hooks:
- - id: isort
- additional_dependencies: [toml]
  - repo: https://github.com/asottile/pyupgrade
  rev: v3.15.0
  hooks:
  - id: pyupgrade
  args: [--py38-plus]
+ - repo: https://github.com/PyCQA/isort
+ rev: 5.12.0
+ hooks:
+ - id: isort
  - repo: https://github.com/psf/black-pre-commit-mirror
  rev: 23.11.0
  hooks:
@@ -32,4 +31,5 @@ repos:
  rev: v2.2.6
  hooks:
  - id: codespell
- additional_dependencies: [tomli]
+ # remove toml extra once Python 3.10 is no longer supported
+ additional_dependencies: ['.[toml]']

changes/2249.misc.rst

@@ -0,0 +1 @@
+Module imports that are dependent on the version of Python are now explicitly structured to declare the Python versions they are dependent on.

core/pyproject.toml

@@ -57,6 +57,7 @@ classifiers = [
 ]
 dependencies = [
  "travertino >= 0.3.0",
+ # limited to <=3.9 for the `group` argument for `entry_points()`
  "importlib_metadata >= 4.4.0; python_version <= '3.9'",
 ]
 

core/src/toga/__init__.py

@@ -105,11 +105,11 @@ def _package_version(file, name):
  # If it *is* in the environment, but the code isn't a git checkout (e.g.,
  # it's been pip installed non-editable) the call to get_version() will fail.
  # If either of these occurs, read version from the installer metadata.
- from importlib import metadata as importlib_metadata
+ import importlib.metadata
 
  # The Toga package names as defined in setup.cfg all use dashes.
  package = "toga-core" if name == "toga" else name.replace("_", "-")
- return importlib_metadata.version(package)
+ return importlib.metadata.version(package)
 
 
 __version__ = _package_version(__file__, __name__)

core/src/toga/platform.py

@@ -3,15 +3,12 @@
 import sys
 from functools import lru_cache
 
-try:
- # Usually, the pattern is "import module; if it doesn't exist,
- # import the shim". However, we need the 3.10 API for entry_points,
- # as the 3.8 didn't support the `groups` argument to entry_points.
- # Therefore, we try to import the compatibility shim first; and fall
- # back to the stdlib module if the shim isn't there.
- from importlib_metadata import entry_points
-except ImportError:
+if sys.version_info >= (3, 10):
  from importlib.metadata import entry_points
+else:
+ # Before Python 3.10, entry_points did not support the group argument;
+ # so, the backport package must be used on older versions.
+ from importlib_metadata import entry_points
 
 
 # Map python sys.platform with toga platforms names

core/tests/test_platform.py

@@ -5,15 +5,12 @@
 
 import toga_dummy
 
-try:
- # Usually, the pattern is "import module; if it doesn't exist,
- # import the shim". However, we need the 3.10 API for entry_points,
- # as the 3.8 didn't support the `groups` argument to entry_points.
- # Therefore, we try to import the compatibility shim first; and fall
- # back to the stdlib module if the shim isn't there.
- from importlib_metadata import EntryPoint
-except ImportError:
+if sys.version_info >= (3, 10):
  from importlib.metadata import EntryPoint
+else:
+ # Before Python 3.10, entry_points did not support the group argument;
+ # so, the backport package must be used on older versions.
+ from importlib_metadata import EntryPoint
 
 import toga.platform
 from toga.platform import current_platform, get_current_platform, get_platform_factory

web/src/toga_web/libs.py

@@ -1,18 +1,16 @@
 try:
- # Try to import js from the PyScript namespace.
+ # Try to import js from the PyScript namespace
  import js
 except ModuleNotFoundError:
- # To ensure the code can be imported, provide a js symbol
- # as a fallback
+ # To ensure the code can be imported, provide a js symbol as a fallback
  js = None
 
 
 try:
- # Try to import pyodide from the PyScript namespace.
+ # Try to import pyodide from the PyScript namespace
  import pyodide
 except ModuleNotFoundError:
- # To ensure the code can be imported, provide a js symbol
- # as a fallback
+ # To ensure the code can be imported, provide a pyodide symbol as a fallback
  pyodide = None