Bump minimum supported Python version to 3.12

.github/workflows/build.yml

@@ -32,7 +32,7 @@ jobs:
     strategy:
       matrix:
         os: ['ubuntu-latest', 'macos-latest']
-        python: ['3.9', '3']  # oldest/newest supported versions
+        python: ['3.12', '3']  # oldest/newest supported versions
     steps:
       - name: Checkout
         uses: actions/checkout@v5
@@ -54,6 +54,7 @@ jobs:
       - name: Inspect
         run: |
           unzip -l dist/*.whl | tee files
+          set -x
           grep -E 'cylc_uiserver.*.dist-info/.*COPYING' files
           grep 'cylc/uiserver/py.typed' files
           grep 'cylc/uiserver/ui' files

.github/workflows/test.yml

@@ -27,10 +27,10 @@ jobs:
       fail-fast: false
       matrix:
         os: ['ubuntu-latest']
-        python-version: ['3.9', '3']
+        python-version: ['3.12', '3']
         include:
           - os: 'macos-latest'
-            python-version: '3.9'  # oldest supported
+            python-version: '3.12'  # oldest supported
     env:
       PYTEST_ADDOPTS: --cov --color=yes
 

changes.d/729.break.md

@@ -0,0 +1 @@
+Minimum supported Python version is now 3.12.

cylc/uiserver/jupyter_config.py

@@ -15,15 +15,8 @@
 
 # Configuration file for jupyterhub.
 
+from importlib.resources import files
 from pathlib import Path
-import sys
-
-
-if sys.version_info[:2] > (3, 8):
-    from importlib.resources import files
-else:
-    # BACK_COMPAT: importlib_resources
-    from importlib_resources import files
 
 from cylc.uiserver import (
     __file__ as uis_pkg,

mypy.ini

@@ -1,5 +1,5 @@
 [mypy]
-python_version = 3.9
+python_version = 3.12
 ignore_missing_imports = True
 files = cylc/uiserver
 # don't run mypy on these files directly

pyproject.toml

@@ -63,15 +63,15 @@ verbosity_assertions = 2
 
 [tool.ruff]
 line-length = 79
-target-version = "py37"
+target-version = "py312"
 
 [tool.ruff.format]
 quote-style = "preserve"
 
 
 [tool.black]
 line-length = 79
-target-version = ['py37']
+target-version = ['py312']
 skip-string-normalization = true
 
 

setup.cfg

@@ -33,17 +33,12 @@ classifiers =
     License :: OSI Approved :: GNU General Public License v3 (GPLv3)
     Operating System :: POSIX
     Programming Language :: Python
-    Programming Language :: Python :: 3.9
-    Programming Language :: Python :: 3.10
-    Programming Language :: Python :: 3.11
-    Programming Language :: Python :: 3.12
-    Programming Language :: Python :: 3.13
     Programming Language :: Python :: 3 :: Only
     Programming Language :: Python :: Implementation :: CPython
 
 [options]
 packages = find_namespace:
-python_requires = >=3.9
+python_requires = >=3.12
 include_package_data = True
 install_requires =
     # NB: We have cylc-flow at the top to force it to install its transitive
@@ -52,7 +47,6 @@ install_requires =
     # bleeding-edge version.
     cylc-flow==8.6.*
     ansimarkup>=1.0.0
-    importlib-resources>=1.3.0; python_version < "3.9"
     jupyter_server>=2.13.0
     requests
     packaging