Add pre-commit hook that checks mypy version consistency (#615)

Author: timmens

.pre-commit-config.yaml

@@ -18,6 +18,16 @@ repos:
         language: python
         always_run: true
         require_serial: true
+  - repo: local
+    hooks:
+      - id: check-mypy-versions
+        name: verify that pre-commits and dev env use the same mypy version
+        entry: python .tools/check_mypy_versions.py
+        language: python
+        always_run: true
+        require_serial: true
+        additional_dependencies:
+          - pyyaml
   - repo: local
     hooks:
       - id: update-algo-selection-code

.tools/check_mypy_versions.py

@@ -0,0 +1,44 @@
+import re
+import sys
+from pathlib import Path
+
+import yaml
+
+
+def _get_mypy_version_from_precommit_config() -> str:
+    config = yaml.safe_load(Path(".pre-commit-config.yaml").read_text())
+    mypy_config = [
+        hook
+        for hook in config["repos"]
+        if hook["repo"] == "https://github.com/pre-commit/mirrors-mypy"
+    ][0]
+    match = re.search(r"v([\d.]+)", mypy_config["rev"])  # Remove "v" prefix
+    if match:
+        return match.group(1)
+    raise ValueError("Mypy version not found in pre-commit config.")
+
+
+def _get_mypy_version_from_conda_environment() -> str:
+    config = yaml.safe_load(Path("environment.yml").read_text())
+    mypy_line = [dep for dep in config["dependencies"] if "mypy" in dep][0]
+    match = re.search(r"mypy=([\d.]+)", mypy_line)
+    if match:
+        return match.group(1)
+    raise ValueError("Mypy version not found in conda environment.")
+
+
+def main() -> None:
+    v_precommit = _get_mypy_version_from_precommit_config()
+    v_conda = _get_mypy_version_from_conda_environment()
+    if v_precommit != v_conda:
+        print(
+            f"Error: Mypy versions do not match:\n"
+            f"  Pre-commit config: {v_precommit}\n"
+            f"  Conda environment: {v_conda}\n"
+        )
+        sys.exit(1)
+    sys.exit(0)
+
+
+if __name__ == "__main__":
+    main()

pyproject.toml

@@ -381,5 +381,6 @@ module = [
     "pdbp",
     "iminuit",
     "nevergrad",
+    "yaml",
   ]
 ignore_missing_imports = true