Add local pre-commit Codecov YAML validator

.pre-commit-config.yaml

@@ -1,7 +1,7 @@
 ci:
   autofix_prs: false
   autoupdate_schedule: "quarterly"
-  skip: [no-commit-to-branch]
+  skip: [no-commit-to-branch, validate-codecov-yaml]
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v6.0.0
@@ -33,6 +33,11 @@ repos:
         files: ^.*\.(py|md|rst|yml)$
   - repo: local
     hooks:
+      - id: validate-codecov-yaml
+        name: validate codecov.yml
+        entry: python scripts/check_codecov_yaml.py
+        language: python
+        files: ^codecov\.yml$
       - id: check-space-packet-parser-metadata
         name: check space_packet_parser metadata
         entry: python scripts/check_metadata.py

scripts/check_codecov_yaml.py

@@ -0,0 +1,68 @@
+"""Validate codecov.yml by posting it to Codecov's validation endpoint."""
+
+from __future__ import annotations
+
+import argparse
+import sys
+from pathlib import Path
+from urllib import error, request
+
+CODECOV_VALIDATE_URL = "https://codecov.io/validate"
+NETWORK_TIMEOUT_SECONDS = 10
+REPO_ROOT = Path(__file__).parent.parent
+
+
+def validate_codecov_yaml(file_path: Path) -> int:
+    """Validate a Codecov YAML file against Codecov's endpoint."""
+    try:
+        request_body = file_path.read_bytes()
+    except OSError as exc:
+        print(f"Unable to read {file_path}: {exc}", file=sys.stderr)
+        return 1
+
+    validate_request = request.Request(CODECOV_VALIDATE_URL, data=request_body, method="POST")
+    try:
+        with request.urlopen(validate_request, timeout=NETWORK_TIMEOUT_SECONDS) as response:  # noqa: S310
+            body = response.read().decode("utf-8", errors="replace").strip()
+    except error.HTTPError as exc:
+        body = exc.read().decode("utf-8", errors="replace").strip()
+        print(f"{file_path} validation failed with HTTP {exc.code}.", file=sys.stderr)
+        if body:
+            print(body, file=sys.stderr)
+        return 1
+    except (error.URLError, TimeoutError, OSError) as exc:
+        print(f"Unable to reach Codecov validation endpoint: {exc}", file=sys.stderr)
+        return 1
+
+    if body:
+        print(body)
+    print(f"{file_path} is valid.")
+    return 0
+
+
+def main() -> int:
+    """Parse CLI args and validate codecov.yml."""
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--file",
+        type=Path,
+        default=REPO_ROOT / "codecov.yml",
+        help="Path to the codecov YAML file to validate.",
+    )
+    parser.add_argument(
+        "files",
+        nargs="*",
+        type=Path,
+        help="Optional file paths provided by pre-commit.",
+    )
+    args = parser.parse_args()
+    files_to_validate = args.files or [args.file]
+    exit_code = 0
+    for file_path in files_to_validate:
+        if validate_codecov_yaml(file_path) != 0:
+            exit_code = 1
+    return exit_code
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())