Apply NEP-29: Pint now requires Python 3.9+ and NumPy 1.21+

.github/workflows/ci.yml

@@ -7,15 +7,15 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.8, 3.9, "3.10", "3.11"]
-        numpy: [null, "numpy>=1.19,<2.0.0"]
+        python-version: [3.9, "3.10", "3.11"]
+        numpy: [null, "numpy>=1.21,<2.0.0"]
         uncertainties: [null, "uncertainties==3.1.6", "uncertainties>=3.1.6,<4.0.0"]
         extras: [null]
         include:
-          - python-version: 3.8 # Minimal versions
+          - python-version: 3.9 # Minimal versions
             numpy: "numpy"
             extras: matplotlib==2.2.5
-          - python-version: 3.8
+          - python-version: 3.9
             numpy: "numpy"
             uncertainties: "uncertainties"
             extras: "sparse xarray netCDF4 dask[complete]==2023.4.0 graphviz babel==2.8"
@@ -92,8 +92,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.8, 3.9, "3.10", "3.11"]
-        numpy: [ "numpy>=1.19,<2.0.0" ]
+        python-version: [3.9, "3.10", "3.11"]
+        numpy: [ "numpy>=1.21,<2.0.0" ]
     runs-on: windows-latest
 
     env:
@@ -153,8 +153,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: [3.8, 3.9, "3.10", "3.11"]
-        numpy: [null, "numpy>=1.19,<2.0.0" ]
+        python-version: [3.9, "3.10", "3.11"]
+        numpy: [null, "numpy>=1.21,<2.0.0" ]
     runs-on: macos-latest
 
     env:

.github/workflows/docs.yml

@@ -14,10 +14,10 @@ jobs:
       - name: Get tags
         run: git fetch --depth=1 origin +refs/tags/*:refs/tags/*
 
-      - name: Set up Python 3.8
+      - name: Set up minimal Python version
         uses: actions/setup-python@v2
         with:
-          python-version: 3.8
+          python-version: 3.9
 
       - name: Get pip cache dir
         id: pip-cache

.readthedocs.yaml

@@ -5,7 +5,7 @@ sphinx:
   configuration: docs/conf.py
   fail_on_warning: false
 python:
-   version: 3.8
+   version: 3.9
    install:
      - requirements: requirements_docs.txt
      - method: pip

README.rst

@@ -43,7 +43,7 @@ and constants. Due to its modular design, you can extend (or even rewrite!)
 the complete list without changing the source code. It supports a lot of
 numpy mathematical operations **without monkey patching or wrapping numpy**.
 
-It has a complete test coverage. It runs in Python 3.8+ with no other dependency.
+It has a complete test coverage. It runs in Python 3.9+ with no other dependency.
 It is licensed under BSD.
 
 It is extremely easy and natural to use:

docs/getting/index.rst

@@ -8,7 +8,7 @@ The getting started guide aims to get you using pint productively as quickly as
 Installation
 ------------
 
-Pint has no dependencies except Python itself. In runs on Python 3.8+.
+Pint has no dependencies except Python itself. In runs on Python 3.9+.
 
 .. grid:: 2
 

docs/getting/overview.rst

@@ -14,7 +14,7 @@ Due to its modular design, you can extend (or even rewrite!) the complete list
 without changing the source code. It supports a lot of numpy mathematical
 operations **without monkey patching or wrapping numpy**.
 
-It has a complete test coverage. It runs in Python 3.8+ with no other
+It has a complete test coverage. It runs in Python 3.9+ with no other
 dependencies. It is licensed under a `BSD 3-clause style license`_.
 
 It is extremely easy and natural to use:

pint/util.py

@@ -1020,9 +1020,7 @@ def sized(y) -> bool:
     return True
 
 
-@functools.lru_cache(
-    maxsize=None
-)  # TODO: replace with cache when Python 3.8 is dropped.
+@functools.cache
 def _build_type(class_name: str, bases):
     return type(class_name, bases, dict())
 

pyproject.toml

@@ -22,12 +22,11 @@ classifiers = [
     "Programming Language :: Python",
     "Topic :: Scientific/Engineering",
     "Topic :: Software Development :: Libraries",
-    "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11"
 ]
-requires-python = ">=3.8"
+requires-python = ">=3.9"
 dynamic = ["version"]
 
 [tool.setuptools.package-data]