ci: rework minimum requirements check

Author: gadomski

.github/setup/action.yml

@@ -4,10 +4,6 @@ inputs:
   python-version:
     description: Python version to set up w/ conda
     required: True
-  pip-cache-hash:
-    description: The hash used for the pip cache
-    required: False
-    default: ${{ hashFiles('setup.cfg', 'requirements-dev.txt') }}
 runs:
   using: composite
   steps:
@@ -21,7 +17,7 @@ runs:
       uses: actions/cache@v2
       with:
         path: ~/.cache/pip
-        key: ${{ runner.os }}-pip-${{ inputs.pip-cache-hash }}
+        key: ${{ runner.os }}-pip-${{ hashFiles('setup.cfg', 'requirements-dev.txt') }}
         restore-keys: ${{ runner.os }}-pip-
     - name: Set up pre-commit cache
       uses: actions/cache@v2

.github/workflows/continuous-integration.yml

@@ -63,15 +63,12 @@ jobs:
       - uses: ./.github/setup
         with:
           python-version: ${{ matrix.python-version }}
-          pip-cache-hash: ${{ hashFiles('requirements-min.txt', 'requirements-dev.txt') }}
-      - name: Install minimum requirements
-        run: pip install -r requirements-min.txt
-      - name: Install the package
-        run: pip install .
       - name: Install development dependencies
         run: pip install -r requirements-dev.txt
-      - name: Check minimum requirements
-        run: scripts/check_minimum_requirements
+      - name: Install the minimum requirements
+        run: scripts/install-min-requirements
+      - name: Install the package
+        run: pip install .
       - name: Test
         run: scripts/test
   pre-release-versions:

requirements-min.txt

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+
+"""Installs the minimum version of all stactools dependencies, with pip.
+
+Assumptions:
+- You've installed the development dependencies: `pip install -r requirements-dev.txt`
+- All of the dependencies in setup.cfg are specified with `>=`
+
+For more context on the approach and rationale behind testing against minimum
+requirements, see
+https://www.gadom.ski/2022/02/18/dependency-protection-with-python-and-github-actions.html.
+
+"""
+
+import subprocess
+from configparser import ConfigParser
+from pathlib import Path
+
+from packaging.requirements import Requirement
+
+root = Path(__file__).parents[1]
+setup_cfg = ConfigParser()
+setup_cfg.read(root / "setup.cfg")
+requirements = []
+for install_requires in filter(
+    bool,
+    (i.strip() for i in setup_cfg["options"]["install_requires"].splitlines()),
+):
+    requirement = Requirement(install_requires)
+    assert len(requirement.specifier) == 1
+    specifier = list(requirement.specifier)[0]
+    assert specifier.operator == ">="
+    install_requires = install_requires.replace(">=", "==")
+    requirements.append(install_requires)
+
+subprocess.run(["pip", "install", *requirements])