feat: record the commit a branch scrape read

Six platforms are read from a branch: System.dat, batocera-systems.json, checkBIOS.sh, the MiSTer BiosDB, the RetroPie scriptmodules and the RetroDECK component manifests. Their YAML named the branch, so the native export patched whatever the branch had become since the scrape. Each scraper now resolves the branch head once, reads every file at that commit and writes it into source. The export follows a recorded tarball and a recorded tree as it already followed a raw file URL.

scripts/scraper/misterfpga_scraper.py

@@ -33,6 +33,7 @@ try:
         BaseScraper,
         BiosRequirement,
         _read_limited,
+        fetch_branch_head,
         requirement_entry,
     )
 except ImportError:
@@ -40,13 +41,15 @@ except ImportError:
         BaseScraper,
         BiosRequirement,
         _read_limited,
+        fetch_branch_head,
         requirement_entry,
     )
 
 PLATFORM_NAME = "misterfpga"
 
+BIOSDB_REPO = "ajgowans/BiosDB_MiSTer"
 SOURCE_URL = (
-    "https://raw.githubusercontent.com/ajgowans/BiosDB_MiSTer/db/bios_db.json.zip"
+    "https://raw.githubusercontent.com/ajgowans/BiosDB_MiSTer/{rev}/bios_db.json.zip"
 )
 
 DB_MEMBER = "bios_db.json"
@@ -126,7 +129,10 @@ def system_of(path: str) -> str:
 class Scraper(BaseScraper):
     """Scraper for the MiSTer BiosDB database."""
 
-    def __init__(self, url: str = SOURCE_URL) -> None:
+    def __init__(self, url: str | None = None) -> None:
+        # The database is published on the db branch: the commit read is recorded.
+        if url is None:
+            url = SOURCE_URL.format(rev=fetch_branch_head(BIOSDB_REPO, "db"))
         super().__init__(url=url)
 
     def _fetch_raw(self) -> str:
@@ -220,7 +226,7 @@ class Scraper(BaseScraper):
             "platform": "MiSTer FPGA",
             "version": released,
             "homepage": "https://misterfpga.org",
-            "source": SOURCE_URL,
+            "source": self.url,
             "base_destination": "games",
             "hash_type": "md5",
             "verification_mode": "md5",