fix: pack companions beside a shared BIOS image

Two filename-agnostic cores reading one BIOS folder each scan the same
images. The second scan stopped at an image the first had placed, so a
companion only the second core opens never reached the pack: Recalbox's
libretro PCSX2 reads <bios>.erom beside the images LRPS2 placed in ps2/.

scripts/packextras.py

@@ -697,9 +697,16 @@ def _agnostic_scan_extras(
                         "agnostic_scan": True,
                     }
                     extra["claim_order"] = (4, 0, emu_name)
-                    if not _take(extra, full_dest, seen_dests, taken):
-                        continue
-                    extras.append(extra)
+                    if _take(extra, full_dest, seen_dests, taken):
+                        extras.append(extra)
+                    else:
+                        # The image another core's scan placed is this core's
+                        # too, and so are the companions it reads beside it:
+                        # Recalbox's libretro PCSX2 opens <bios>.erom next to
+                        # the images LRPS2 placed, which LRPS2 never reads.
+                        held = taken.get(full_dest) if taken is not None else None
+                        if held is None or held.get("sha1") != sha1:
+                            continue
                     extras.extend(_companion_extras(
                         _companions(path, scan_name, _companion_extensions(profile, fname), files_db),
                         folder, extras_prefix, seen_dests, profile, emu_name, f, taken,

tests/test_bios_companions.py

@@ -108,6 +108,56 @@ class Companions(unittest.TestCase):
         self.assertIn("SCPH-70004.rom1", names)
         self.assertFalse({"SCPH-70004.ROM1", "cheats_ws.zip", "GameIndex.yaml"} & names)
 
+    def test_a_shared_image_brings_each_cores_companions(self):
+        """Recalbox runs LRPS2 and the old libretro PCSX2 on one ps2/ folder.
+        LRPS2's scan placed SCPH-70004.BIN and its rom1, and the second core's
+        scan stopped at the taken image, so the .erom only it reads stayed out."""
+        import os
+        import tempfile
+
+        from packextras import _agnostic_scan_extras
+
+        def profile(name: str, ext: str) -> dict:
+            return {"emulator": name, "bios_mode": "agnostic", "files": [
+                {"name": "ps2-0230a-20080220.bin", "found_by": "content",
+                 "path": "ps2/ps2-0230a-20080220.bin", "min_size": 8, "max_size": 16},
+                {"name": f"ps2-0230a-20080220.{ext}", "path": f"ps2/ps2-0230a-20080220.{ext}"},
+            ]}
+
+        stored = {
+            "ps2-0230a-20080220.bin": b"I" * 8,
+            "ps2-0230a-20080220.rom1": b"R",
+            "ps2-0230a-20080220.erom": b"E",
+        }
+        with tempfile.TemporaryDirectory() as tmp:
+            cwd = os.getcwd()
+            os.chdir(tmp)
+            try:
+                files, by_name = {}, {}
+                for name, payload in stored.items():
+                    path = f"bios/PS2/{name}"
+                    os.makedirs("bios/PS2", exist_ok=True)
+                    Path(path).write_bytes(payload)
+                    sha1 = f"{len(files):040d}"
+                    files[sha1] = {"path": path, "name": name, "size": len(payload),
+                                   "sha1": sha1}
+                    by_name[name] = [sha1]
+                db = {"files": files, "indexes": {
+                    "by_name": by_name, "by_md5": {}, "by_crc32": {}, "by_path_suffix": {},
+                }}
+                profiles = {"a": profile("A", "rom1"), "b": profile("B", "erom")}
+                extras = _agnostic_scan_extras(
+                    profiles, {"a", "b"}, db, by_name, set(), "", taken={},
+                )
+            finally:
+                os.chdir(cwd)
+        placed = [(e["destination"], e["source_profile"]) for e in extras]
+        self.assertEqual(sorted(placed), [
+            ("ps2/ps2-0230a-20080220.bin", "a"),
+            ("ps2/ps2-0230a-20080220.erom", "b"),
+            ("ps2/ps2-0230a-20080220.rom1", "a"),
+        ])
+
     def test_pcsx2_profiles_name_no_free_standing_companion(self):
         for name in ("pcsx2", "pcsx2-legacy"):
             profile = yaml.safe_load((REPO_ROOT / "emulators" / f"{name}.yml").read_text())