scripts: ci: add vermin (min python version check)

Add a compliance check that allows to flag when a given file requires a
Python version higher than 3.10 (minimum supported version in Zephyr at
the time of writing) since not all Python scripts are tested against
3.10 in CI and we want to avoid introducing changes that could break
users.

Signed-off-by: Benjamin Cabé <benjamin@zephyrproject.org>

.gitignore

@@ -102,6 +102,7 @@ MaintainersFormat.txt
 ModulesMaintainers.txt
 Nits.txt
 Pylint.txt
+PythonCompat.txt
 Ruff.txt
 SphinxLint.txt
 SysbuildKconfig.txt

scripts/ci/check_compliance.py

@@ -1815,6 +1815,66 @@ class Ruff(ComplianceTest):
                 desc = f"Run 'ruff format {file}'"
                 self.fmtd_failure("error", "Python format error", file, desc=desc)
 
+class PythonCompatCheck(ComplianceTest):
+    """
+    Python Compatibility Check
+    """
+    name = "PythonCompat"
+    doc = "Check that Python files are compatible with Zephyr minimum supported Python version."
+
+    MAX_VERSION = (3, 10)
+    MAX_VERSION_STR = f"{MAX_VERSION[0]}.{MAX_VERSION[1]}"
+
+    def run(self):
+        py_files = [f for f in get_files(filter="d") if f.endswith(".py")]
+        if not py_files:
+            return
+        cmd = ["vermin", "-f", "parsable", "--violations",
+               f"-t={self.MAX_VERSION_STR}", "--no-make-paths-absolute"] + py_files
+        try:
+            result = subprocess.run(cmd,
+                                    check=False,
+                                    capture_output=True,
+                                    cwd=GIT_TOP)
+        except Exception as ex:
+            self.error(f"Failed to run vermin: {ex}")
+        output = result.stdout.decode("utf-8")
+        failed = False
+        for line in output.splitlines():
+            parts = line.split(":")
+            if len(parts) < 6:
+                continue
+            filename, line_number, column, _, py3ver, feature = parts[:6]
+            if not line_number:
+                # Ignore all file-level messages
+                continue
+
+            desc = None
+            if py3ver.startswith('!'):
+                desc = f"{feature} is known to be incompatible with Python 3."
+            elif py3ver.startswith('~'):
+                # "no known reason it won't work", just skip
+                continue
+            else:
+                major, minor = map(int, py3ver.split(".")[:2])
+                if (major, minor) > self.MAX_VERSION:
+                    desc = f"{feature} requires Python {major}.{minor}, which is higher than " \
+                           f"Zephyr's minimum supported Python version ({self.MAX_VERSION_STR})."
+
+            if desc is not None:
+                self.fmtd_failure(
+                    "error",
+                    "PythonCompat",
+                    filename,
+                    line=int(line_number),
+                    col=int(column) if column else None,
+                    desc=desc,
+                )
+                failed = True
+        if failed:
+            self.failure("Some Python files use features that are not compatible with Python " \
+                         f"{self.MAX_VERSION_STR}.")
+
 
 class TextEncoding(ComplianceTest):
     """

scripts/requirements-actions.in

@@ -35,6 +35,7 @@ tabulate
 tomli>=1.1.0
 tox
 unidiff
+vermin
 west>=0.14.0
 xlsxwriter
 yamllint

scripts/requirements-actions.txt

@@ -1235,6 +1235,10 @@ urllib3==2.4.0 \
     #   elastic-transport
     #   pygithub
     #   requests
+vermin==1.6.0 \
+    --hash=sha256:6266ca02f55d1c2aa189a610017c132eb2d1934f09e72a955b1eb3820ee6d4ef \
+    --hash=sha256:f1fa9ee40f59983dc40e0477eb2b1fa8061a3df4c3b2bcf349add462a5610efb
+    # via -r requirements-actions.in
 virtualenv==20.31.2 \
     --hash=sha256:36efd0d9650ee985f0cad72065001e66d49a6f24eb44d98980f630686243cf11 \
     --hash=sha256:e10c0a9d02835e592521be48b332b6caee6887f332c111aa79a09b9e79efc2af

scripts/requirements-compliance.txt

@@ -13,5 +13,6 @@ python-magic; sys_platform != "win32"
 ruff==0.11.11
 sphinx-lint
 unidiff
+vermin
 yamllint
 # zephyr-keep-sorted-stop