fix: group core files under their pack path

On a platform that writes bios/ in front of its destinations (RetroDECK, AmberELEC, EmuELEC), a core extra was grouped, dropped and held under its bare destination while the platform's declaration of the same file used bios/<name>. Beetle PSX's scph5501.bin was kept by the --region japan pack while the declaration was dropped and the installer dropped the path. extra_region_key keys every extra with the platform's declared root, in the builder, the manifest selection, verify's replay and the omissions. The same key gives the declared entries the systems of the core files at their path: every --system case of RetroDECK differed between pack and installer before, none does now.

scripts/generate_pack.py

@@ -1250,7 +1250,7 @@ def generate_pack(
           if required_only and fe.get("required") is False:
               continue
           dest = sanitize_pack_path(fe.get("destination", fe["name"]))
-          if region_drops and dest in region_drops:
+          if region_drops and extra_region_key(fe, declared_root(config)) in region_drops:
               continue
           if not dest:
               continue
@@ -4168,7 +4168,8 @@ def _manifest_core_entries(
         dest = sanitize_pack_path(fe.get("destination", fe["name"]))
         if not dest:
             continue
-        if region_drops and dest in region_drops:
+        region_key = extra_region_key(fe, declared_root(config))
+        if region_drops and region_key in region_drops:
             continue
         full_dest = extra_full_destination(fe, extras_pfx)
         if not full_dest:
@@ -4242,7 +4243,7 @@ def _manifest_core_entries(
         entry, file_size = _manifest_entry(
             local_path, manifest_dest, [source_emu] if source_emu else [],
             db, repo_root,
-            selection.fields(dest, fe.get("name", "")),
+            selection.fields(region_key, fe.get("name", "")),
         )
         if entry is not None and save_root:
             entry.update(save_entry_fields(fe))
@@ -4356,7 +4357,8 @@ def _manifest_selection(
         else set()
     )
     return drops, SelectionIndex.build(
-        region_groups, region_index, pack_systems, extras, required_only
+        region_groups, region_index, pack_systems, extras, required_only,
+        extras_prefix=declared_root(config),
     ), held
 
 
@@ -4381,7 +4383,9 @@ def _record_absent(
         if required_only and fe.get("required") is False:
             continue
         dest = sanitize_pack_path(fe.get("destination", fe.get("name", "")))
-        if not dest or (region_drops and dest in region_drops):
+        if not dest or (
+            region_drops and extra_region_key(fe, declared_root(config)) in region_drops
+        ):
             continue
         full_dest = extra_full_destination(fe, extras_pfx)
         if not full_dest:
@@ -4576,8 +4580,10 @@ def generate_manifest(
         reason: str,
         cores: list[str] | None,
     ) -> None:
-        bare = sanitize_pack_path(
-            file_entry.get("destination", file_entry.get("name", ""))
+        # A core extra (cores given) is keyed as the region pass keys it.
+        bare = (
+            sanitize_pack_path(file_entry.get("destination", file_entry.get("name", "")))
+            if cores is None else extra_region_key(file_entry, declared_root(config))
         )
         save_root = file_entry.get("root") == "save"
         omitted_by_destination[full_destination] = {
@@ -5464,6 +5470,7 @@ from packpaths import (  # noqa: E402,F401
 from packextras import (  # noqa: E402,F401
     ExtraResolver,
     extra_full_destination,
+    extra_region_key,
     prefixed_destination,
     save_entry_fields,
     save_manifest_dest,