fix: emulator region report reads the pack drop set

scripts/generate_pack.py

@@ -1283,25 +1283,9 @@ def generate_emulator_pack(
     zip_path = os.path.join(output_dir, zip_name)
     os.makedirs(output_dir, exist_ok=True)
 
-    # One group per system (or explicit variant_group) inside each profile.
-    # Multi-system cores such as O2EM therefore retain a fallback BIOS for
-    # every system instead of letting one matching system empty another.
-    region_drops: set[str] = set()
-    if regions:
-        region_index = region_mod.build_region_index(dict(selected))
-        region_groups: dict[str, list[tuple[str, str]]] = {}
-        for emu_name, profile in sorted(selected):
-            structure = profile.get("pack_structure")
-            for fe in filter_files_by_mode(profile.get("files", []), standalone):
-                dest = _resolve_destination(fe, structure, standalone)
-                if dest:
-                    group_id = _emulator_region_group(emu_name, profile, fe)
-                    region_groups.setdefault(group_id, []).append(
-                        (dest, fe.get("name", ""))
-                    )
-        region_drops = region_mod.resolve_region_drops(
-            region_groups, region_index, regions
-        )
+    region_drops: set[str] = (
+        emulator_region_drops(selected, standalone, regions) if regions else set()
+    )
 
     total_files = 0
     missing_files = []
@@ -3436,6 +3420,7 @@ from packextras import (  # noqa: E402,F401
     _collect_emulator_extras,
     _extra_system_ids,
     platform_region_groups,
+    emulator_region_drops,
     _emulator_region_group,
 )
 

scripts/packextras.py

@@ -600,6 +600,34 @@ def platform_region_groups(
             groups.setdefault(group_id, []).append((dest, name))
     return groups, extra_dests
 
+def emulator_region_drops(
+    selected: list[tuple[str, dict]], standalone: bool, regions: list[str]
+) -> set[str]:
+    """Destinations an emulator-mode `--region` withdraws.
+
+    One group per system (or explicit variant_group) inside each profile, so
+    a multi-system core such as O2EM keeps a fallback BIOS for every system
+    instead of letting one matching system empty another. The emulator pack
+    and `verify --emulator` both read this, keyed by pack destination.
+    """
+    import region as region_mod
+    from packpaths import _resolve_destination
+    from validation import filter_files_by_mode
+
+    region_index = region_mod.build_region_index(dict(selected))
+    region_groups: dict[str, list[tuple[str, str]]] = {}
+    for emu_name, profile in sorted(selected):
+        structure = profile.get("pack_structure")
+        for fe in filter_files_by_mode(profile.get("files", []), standalone):
+            dest = _resolve_destination(fe, structure, standalone)
+            if dest:
+                group_id = _emulator_region_group(emu_name, profile, fe)
+                region_groups.setdefault(group_id, []).append(
+                    (dest, fe.get("name", ""))
+                )
+    return region_mod.resolve_region_drops(region_groups, region_index, regions)
+
+
 def _emulator_region_group(emu_name: str, profile: dict, file_entry: dict) -> str:
     """Stable group ID for regional alternatives within an emulator profile."""
     variant = file_entry.get("variant_group")

scripts/verify.py

@@ -1242,7 +1242,7 @@ def verify_emulator(
     """Verify files for specific emulator profiles.
 
     A region priority list narrows the report the same way a pack built with the
-    same list would be narrowed. One group per profile, as in generate_pack.
+    same list would be narrowed, through the emulator pack's own drop set.
     """
     load_emulator_profiles(emulators_dir)
     zip_contents = build_zip_contents_index(db)
@@ -1265,22 +1265,12 @@ def verify_emulator(
     dest_to_name: dict[str, str] = {}
     data_dir_notices: list[str] = []
 
+    # The emulator pack withdraws these; the report withdraws the same.
     region_drops: set[str] = set()
     if regions:
-        import region as region_mod
+        from packextras import emulator_region_drops
 
-        region_index = region_mod.build_region_index(dict(selected))
-        region_groups: dict[str, list[tuple[str, str]]] = {}
-        for emu_name, profile in selected:
-            members = region_groups.setdefault(emu_name, [])
-            for fe in filter_files_by_mode(profile.get("files", []), standalone):
-                nm = fe.get("name", "")
-                key = fe.get("path") or nm
-                if key:
-                    members.append((key, nm))
-        region_drops = region_mod.resolve_region_drops(
-            region_groups, region_index, regions
-        )
+        region_drops = emulator_region_drops(selected, standalone, regions)
 
     for emu_name, profile in selected:
         files = expand_directory_entries(
@@ -1289,10 +1279,13 @@ def verify_emulator(
             standalone,
         )
         if region_drops:
+            from packpaths import _resolve_destination
+
+            structure = profile.get("pack_structure")
             files = [
                 fe
                 for fe in files
-                if (fe.get("path") or fe.get("name", "")) not in region_drops
+                if _resolve_destination(fe, structure, standalone) not in region_drops
             ]
 
         # Check data directories (only notice if not cached)