MNT: Add update_requirements tool to copy from setup.cfg

tools/update_requirements.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+import sys
+from copy import copy
+from configparser import ConfigParser
+from pathlib import Path
+from packaging.requirements import Requirement, SpecifierSet
+
+repo_root = Path(__file__).parent.parent
+setup_cfg = repo_root / "setup.cfg"
+reqs = repo_root / "requirements.txt"
+min_reqs = repo_root / "min-requirements.txt"
+
+config = ConfigParser()
+config.read(setup_cfg)
+requirements = [Requirement(req)
+                for req in config.get("options", "install_requires").strip().splitlines()]
+
+script_name = Path(__file__).relative_to(repo_root)
+
+def to_min(req):
+    if req.specifier:
+        req = copy(req)
+        min_spec = [spec for spec in req.specifier if spec.operator in ('>=', '~=')][0]
+        min_spec._spec = ('==', ) + min_spec._spec[1:]
+        req.specifier = SpecifierSet(str(min_spec))
+    return req
+
+lines = [f"# Auto-generated by {script_name}", ""]
+
+# Write requirements
+lines[1:-1] = [str(req) for req in requirements]
+reqs.write_text("\n".join(lines))
+
+# Write minimum requirements
+lines[1:-1] = [str(to_min(req)) for req in requirements]
+min_reqs.write_text("\n".join(lines))