Validate 'Created:' dates on CI

.pre-commit-config.yaml

@@ -4,3 +4,12 @@ repos:
     hooks:
       - id: rst-backticks
       - id: rst-inline-touching-normal
+
+  - repo: local
+    hooks:
+      - id: validate-created
+        name: "Lint Created: dates"
+        language: system
+        entry: python3 scripts/validate-created.py
+        files: ^pep-\d+\.(rst|txt)$
+        types: [text]

scripts/validate-created.py

@@ -0,0 +1,52 @@
+"""
+Validates the 'Created: ' field of PEPs match %d-%b-%Y as specified in PEP 1.
+
+Requires Python 3.6+
+
+Usage: python3 validate-created.py filename1 [filename2 [...]]
+"""
+import sys
+from datetime import datetime as dt
+
+COL_NUMBER = len("Created: ")
+
+
+def validate_file(filename: str) -> int:
+    errors = 0
+    found = False
+    line_number = 0
+
+    with open(filename, encoding="utf8") as f:
+        for line in f:
+            line_number += 1
+            if line.startswith("Created: "):
+                found = True
+                break
+
+    if not found:
+        errors += 1
+        print(f"{filename}: 'Created:' not found")
+        return errors
+
+    date = line.split()[1]
+    try:
+        # Validate
+        dt.strptime(date, "%d-%b-%Y")
+    except ValueError as e:
+        print(f"{filename}:{line_number}:{COL_NUMBER}: {e}")
+        errors += 1
+
+    return errors
+
+
+def main(argv: list) -> None:
+    assert len(argv) >= 2, "Missing required filename parameter(s)"
+    total_errors = 0
+    for filename in argv[1:]:
+        total_errors += validate_file(filename)
+
+    sys.exit(total_errors)
+
+
+if __name__ == "__main__":
+    main(sys.argv)