Sync python versions;use pixi.toml as source of truth

.pre-commit-config.yaml

@@ -53,3 +53,11 @@ repos:
       - id: actionlint
         # Disable because of false-positive SC2046
         args: ["-shellcheck="]
+  - repo: local
+    hooks:
+      - id: sync-python-version
+        name: sync python version with pixi.toml
+        entry: python tools/sync-python-version.py
+        language: python
+        files: '(pixi\.toml|pyproject\.toml)$'
+        pass_filenames: false

packages/essimaging/pyproject.toml

@@ -24,6 +24,8 @@ classifiers = [
     "Topic :: Scientific/Engineering",
     "Typing :: Typed",
 ]
+# The min python version should be updated in the root pixi.toml file
+# pre-commit will automatically update the following pin
 requires-python = ">=3.11"
 
 dynamic = ["version"]

packages/essreduce/pyproject.toml

@@ -24,6 +24,8 @@ classifiers = [
     "Topic :: Scientific/Engineering",
     "Typing :: Typed",
 ]
+# The min python version should be updated in the root pixi.toml file
+# pre-commit will automatically update the following pin
 requires-python = ">=3.11"
 
 dynamic = ["version"]

tools/sync-python-version.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (c) Scipp contributors (https://github.com/scipp)
+"""Sync requires-python with pixi.toml.
+
+The Python minor version pinned in pixi.toml (e.g. ``python = "3.12.*"``)
+is the single source of truth. This script updates:
+
+* ``requires-python`` in ``packages/*/pyproject.toml``
+"""
+
+import re
+import sys
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parent.parent
+PIXI_TOML = ROOT / "pixi.toml"
+PACKAGES = ROOT / "packages"
+
+
+def python_minor_version_from_pixi() -> str:
+    text = PIXI_TOML.read_text()
+    m = re.search(r'^python\s*=\s*"(\d+\.\d+)\.\*"', text, re.MULTILINE)
+    if not m:
+        print(f'ERROR: Could not find python = "X.Y.*" in {PIXI_TOML}')
+        sys.exit(1)
+    return m.group(1)
+
+
+def sync_requires_python(version: str) -> bool:
+    changed = False
+    expected = f'requires-python = ">={version}"'
+    pattern = re.compile(r'^requires-python\s*=\s*"[^"]*"', re.MULTILINE)
+    for pyproject in sorted(PACKAGES.glob("*/pyproject.toml")):
+        text = pyproject.read_text()
+        m = pattern.search(text)
+        if m is None:
+            continue
+        if m.group(0) != expected:
+            new_text = text[: m.start()] + expected + text[m.end() :]
+            pyproject.write_text(new_text)
+            print(f"Updated {pyproject.relative_to(ROOT)}")
+            changed = True
+    return changed
+
+
+def main() -> int:
+    version = python_minor_version_from_pixi()
+    changed = sync_requires_python(version)
+    if changed:
+        print(
+            f'Files updated to match python = "{version}.*" from pixi.toml. '
+            "Please stage the changes."
+        )
+        return 1
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())