fix: refuse Python 3.8 in every build script

Only generate_pack.py and pipeline.py checked the interpreter. verify.py,
slots.py, validate_pr.py, cross_reference.py and the probe tools started
under 3.8 and stopped halfway on a str.removeprefix AttributeError. The
check now lives in common.py, which every build script imports, and in
core_probe.py and region_check.py, which do not. generate_site.py imports
common before siterender, which raised a TypeError at load under 3.8.

scripts/campaign.py

@@ -83,14 +83,17 @@ from collections.abc import Callable, Iterator, Sequence
 from dataclasses import dataclass, field
 from pathlib import Path
 
-import yaml
-
 sys.path.insert(0, str(Path(__file__).resolve().parent))
 
+# First: core_probe stops an interpreter older than 3.9 before anything else
+# fails on it.
+import core_probe
+
+import yaml
+
 import autorun
 import campaign_profiles
 import campaign_rules as rules
-import core_probe
 import measurement_records as mr
 
 ROOT = Path(__file__).resolve().parent.parent

scripts/common.py

@@ -20,6 +20,15 @@ import sys
 import zipfile
 from pathlib import Path
 
+# Every build script imports this module. verify.py, slots.py, validate_pr.py
+# and cross_reference.py started under 3.8 and stopped halfway on a
+# str.removeprefix AttributeError, which named no version.
+if sys.version_info < (3, 9):
+    sys.exit(
+        f"{Path(sys.argv[0]).name} needs Python 3.9 or newer, "
+        f"this is {sys.version.split()[0]}"
+    )
+
 
 try:
     import yaml

scripts/core_probe.py

@@ -40,6 +40,14 @@ from collections.abc import Iterable, Iterator, Sequence
 from dataclasses import dataclass, field
 from pathlib import Path
 
+# The probe tools do not import common.py, which states the 3.9 floor for the
+# other scripts. Under 3.8 they stopped on a str.removesuffix AttributeError.
+if sys.version_info < (3, 9):
+    sys.exit(
+        f"{Path(sys.argv[0]).name} needs Python 3.9 or newer, "
+        f"this is {sys.version.split()[0]}"
+    )
+
 ROOT = Path(__file__).resolve().parent.parent
 MIN_BENCH_REPETITIONS = 5
 DEFAULT_WORK_DIR = ROOT / "tmp" / "core_probe"

scripts/generate_site.py

@@ -14,7 +14,6 @@ Usage:
 
 from __future__ import annotations
 
-from siterender import SECTION_LABELS, WIKI_SRC_DIR
 import argparse
 import csv
 import hashlib
@@ -64,6 +63,7 @@ from common import (
     unique_emulator_profiles,
     yaml_load,
 )
+from siterender import SECTION_LABELS, WIKI_SRC_DIR
 from artifacts import ArtifactLockBusy, artifact_lock
 from artifacts import json_text as _json_text
 from cross_reference import FileConsumers, entry_target, held_copy

scripts/region_check.py

@@ -36,6 +36,14 @@ import urllib.request
 from collections.abc import Callable, Iterable
 from pathlib import Path
 
+# The probe tools do not import common.py, which states the 3.9 floor for the
+# other scripts. Under 3.8 they stopped on a str.removesuffix AttributeError.
+if sys.version_info < (3, 9):
+    sys.exit(
+        f"{Path(sys.argv[0]).name} needs Python 3.9 or newer, "
+        f"this is {sys.version.split()[0]}"
+    )
+
 sys.path.insert(0, str(Path(__file__).resolve().parent))
 
 import yaml  # noqa: E402