fix: send moved part cards to the emulator index

Adding one entry to mame.yml moves 938 cards from one part page to the
next, and a published emulators/mame-files-1/#file-... address landed
on a page without the card. A part page now sends a file- id it does
not hold to the emulator page, whose card index row opens the part that
holds it.

tests/test_site_exports.py

@@ -866,6 +866,31 @@ class AWantedDumpIsFoundByItsHash(unittest.TestCase):
         self.assertIn('retired_files.load(_REPO_ROOT / "retired.json"), wanted)', source)
 
 
+class AMovedPartCardReachesItsPage(unittest.TestCase):
+    """One entry added to mame.yml moved 938 of its 1,585 cards from one
+    part page to another, and emulators/mame-files-1/#file-mackbd-m0110a-zip
+    led to a page without the card: part pages have no card index, and
+    site.js redirected only sha1- ids."""
+
+    def test_a_part_page_sends_a_missing_card_to_the_emulator_page(self):
+        import re as _re  # noqa: PLC0415
+
+        import generate_site  # noqa: PLC0415
+
+        script = (Path(__file__).resolve().parents[1] / "website" / "src" / "scripts"
+                  / "site.ts").read_text(encoding="utf-8")
+        body = script.split("const followMovedCard = () => {", 1)[1].split("\n};", 1)[0]
+        pattern = _re.search(r"const part = /(.+?)/\.exec\(location\.pathname\)", body).group(1)
+        files = [{"name": f"f{i}.bin", "path": f"f{i}.bin", "required": True} for i in range(600)]
+        stem = generate_site.emulator_parts("mame", files)[1][0]
+        found = _re.search(pattern.replace("\\/", "/"), f"/retrobios/emulators/{stem}/")
+        self.assertEqual(found.group(1), "mame")
+        self.assertIn("emulators/${part[1]}/#", body)
+        self.assertIn("id.startsWith('file-')", body)
+        # The emulator page holds the index whose row leads to the card.
+        self.assertIn("closest('.rb-card-index tr')", body)
+
+
 class AFileHasAnAddressByContent(unittest.TestCase):
     """mt32_control.rom moved from the Commodore page to the Roland page and
     every link to its card broke: the anchor was content-based, the page

website/src/scripts/site.ts

@@ -814,7 +814,10 @@ const resolveFileAddress = () => {
 
 // A file card moved to another page keeps its address: an id of the form
 // sha1-<12 hex> that this page does not hold is looked up by content, and
-// an emulator card listed in the table of a split page opens its page.
+// an emulator card listed in the table of a split page opens its page. A
+// part of a split emulator page (emulators/mame-files-1/) sends a card id
+// it no longer holds to that table: an entry added to the profile moves
+// hundreds of cards from one part to the next.
 const followMovedCard = () => {
 	const id = decodeURIComponent(location.hash.slice(1));
 	if (!id) return;
@@ -824,8 +827,14 @@ const followMovedCard = () => {
 		location.replace(link.href);
 		return;
 	}
+	if (target) return;
 	const match = /^sha1-([0-9a-f]{12})$/.exec(id);
-	if (match && !target) location.replace(new URL(`files/?sha1=${match[1]}`, siteRoot()));
+	if (match) {
+		location.replace(new URL(`files/?sha1=${match[1]}`, siteRoot()));
+		return;
+	}
+	const part = /\/emulators\/(.+)-files-\d+\/?$/.exec(location.pathname);
+	if (part && id.startsWith('file-')) location.replace(new URL(`emulators/${part[1]}/#${encodeURIComponent(id)}`, siteRoot()));
 };
 
 // A link to a card folded in a table row (emulators with many entries)