fix: games tools write whole files, name options

The games importers wrote through fixed .part names, the new options had
no help text, and romfolders stopped on the first setup the offline cache
lacked. RetroArch's rom folder map is regenerated from its source spec
(path null, as the schema says). The installer's Python 3.8 job imports
the games tests without pyyaml, so the region rules load lazily.

scripts/scraper/romfolders/__main__.py

@@ -14,6 +14,8 @@ from pathlib import Path
 import yaml
 
 from . import Fetcher, SourceError, load_sources, scrape_setup
+from upstream import UpstreamError  # noqa: E402  (the package puts scripts/ on sys.path)
+from artifacts import write_text_atomic  # noqa: E402
 from ..base_scraper import _PlatformDumper
 
 DEFAULT_DIR = Path("platforms") / "romfolders"
@@ -31,8 +33,10 @@ def main() -> int:
     which.add_argument("--setup", action="append", help="setup id (repeatable)")
     which.add_argument("--all", action="store_true", help="every setup of the sources file")
     which.add_argument("--list", action="store_true", help="list the setups and their format")
-    parser.add_argument("--sources", type=Path, default=DEFAULT_DIR / "_sources")
-    parser.add_argument("--output-dir", type=Path, default=DEFAULT_DIR)
+    parser.add_argument("--sources", type=Path, default=DEFAULT_DIR / "_sources",
+                        help="the setups, their repositories and pinned revisions")
+    parser.add_argument("--output-dir", type=Path, default=DEFAULT_DIR,
+                        help=f"where <setup>.yml is written (default {DEFAULT_DIR})")
     parser.add_argument("--offline", action="store_true", help="read the revision cache only")
     parser.add_argument("--dry-run", action="store_true", help="print counts, write nothing")
     args = parser.parse_args()
@@ -53,7 +57,7 @@ def main() -> int:
         fetcher = Fetcher(spec.get("sources", {}), offline=args.offline)
         try:
             doc = scrape_setup(setup, spec, fetcher)
-        except (SourceError, ValueError, KeyError, OSError) as exc:
+        except (SourceError, UpstreamError, ValueError, KeyError, OSError) as exc:
             print(f"FAIL {setup}: {exc}", file=sys.stderr)
             failed += 1
             continue
@@ -63,7 +67,7 @@ def main() -> int:
             target = args.output_dir / f"{setup}.yml"
             text = dump_setup(doc)
             if not target.exists() or target.read_text(encoding="utf-8") != text:
-                target.write_text(text, encoding="utf-8")
+                write_text_atomic(str(target), text)
     return 1 if failed else 0