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/retropie_scraper.py

@@ -26,15 +26,13 @@ import urllib.error
 import urllib.request
 
 try:
-    from .base_scraper import BaseScraper, BiosRequirement
+    from .base_scraper import BaseScraper, BiosRequirement, fetch_branch_head
 except ImportError:
-    from base_scraper import BaseScraper, BiosRequirement
+    from base_scraper import BaseScraper, BiosRequirement, fetch_branch_head
 
 PLATFORM_NAME = "retropie"
 
-SOURCE_URL = (
-    "https://codeload.github.com/RetroPie/RetroPie-Setup/tar.gz/refs/heads/master"
-)
+SOURCE_URL = "https://codeload.github.com/RetroPie/RetroPie-Setup/tar.gz/{rev}"
 GITHUB_REPO = "RetroPie/RetroPie-Setup"
 MAX_ARCHIVE = 64 * 1024 * 1024
 
@@ -51,7 +49,10 @@ _PACKAGE_DIRS = ("emulators", "libretrocores", "ports")
 class Scraper(BaseScraper):
     """Scraper for the RetroPie package list."""
 
-    def __init__(self, url: str = SOURCE_URL) -> None:
+    def __init__(self, url: str | None = None) -> None:
+        # The package list is read from master: the commit read is recorded.
+        if url is None:
+            url = SOURCE_URL.format(rev=fetch_branch_head(GITHUB_REPO, "master"))
         super().__init__(url=url)
         self._modules: list[str] | None = None
         self._version = ""
@@ -135,7 +136,7 @@ class Scraper(BaseScraper):
             "platform": "RetroPie",
             "version": self._version,
             "homepage": "https://retropie.org.uk",
-            "source": SOURCE_URL,
+            "source": self.url,
             "base_destination": "BIOS",
             "cores": cores,
         }