fix: propose retropie names per core, never into or-lists

scripts/exporter/retropie_exporter.py

@@ -142,12 +142,23 @@ class Exporter(BaseExporter):
 
     @classmethod
     def _insertion_point(cls, help_text: str) -> int | None:
-        """Where a name joins the list, or None when there is no list."""
+        """Where a name joins the list, or None when there is no list.
+
+        A list of alternatives ("a or b", "a/b") is not an enumeration: an
+        appended ", c" reads as one more required file and the plural turns
+        "one of these" into "all of these". Such a list is left alone.
+        """
         clause = _BIOS_CLAUSE.search(help_text)
         if clause is None:
             return None
-        names = cls._names_in(clause.group(0))
-        return clause.start() + names[-1].end() if names else None
+        text = clause.group(0)
+        names = cls._names_in(text)
+        if not names:
+            return None
+        between = text[names[0].start():names[-1].end()]
+        if re.search(r"\bor\b|/", between):
+            return None
+        return clause.start() + names[-1].end()
 
     @staticmethod
     def _in_search_order(candidates: list[NativeFile]) -> list[str]:
@@ -164,6 +175,19 @@ class Exporter(BaseExporter):
                 names.append(fe.name)
         return names
 
+    @staticmethod
+    def _required_for(fe: NativeFile, core: str) -> bool:
+        """Whether the package's own core needs the file.
+
+        The merged `required` is true when any core needs it: pcsx_rearmed
+        runs in HLE without a BIOS, yet four were proposed as required for
+        its package because other PSX cores require them.
+        """
+        required_by = (fe.truth or {}).get("_required_by")
+        if required_by is None:
+            return fe.required
+        return core in required_by
+
     @staticmethod
     def _join(names: list[str]) -> str:
         """RetroPie's own idiom: a, b and c."""
@@ -235,7 +259,7 @@ class Exporter(BaseExporter):
             candidates = [
                 fe
                 for fe in files
-                if fe.required
+                if self._required_for(fe, core or "")
                 and not (
                     {fe.name.lower()}
                     | {str(a).lower() for a in (fe.native("aliases", []) or [])}

scripts/truth.py

@@ -123,6 +123,10 @@ def _merge_file_into_system(
             existing.setdefault("_source_refs", set())
         if file_entry.get("required") and not existing.get("required"):
             existing["required"] = True
+        if file_entry.get("required"):
+            # Which cores need it: `required` above is the union, true when
+            # any core needs it, and a package of one core must not read it.
+            existing["_required_by"] = existing.get("_required_by", set()) | {emu_name}
         for h in ("sha1", "md5", "sha256", "crc32"):
             theirs = file_entry.get(h, "")
             ours = existing.get(h, "")
@@ -214,6 +218,7 @@ def _merge_file_into_system(
     elif isinstance(crc, str) and crc != crc.lower():
         entry["crc32"] = crc.lower()
     entry["_cores"] = {emu_name}
+    entry["_required_by"] = {emu_name} if file_entry.get("required") else set()
     sr = file_entry.get("source_ref")
     if sr is not None:
         sr_key = _serialize_source_ref(sr)
@@ -387,6 +392,7 @@ def generate_platform_truth(
     for sys_id, sys_data in systems.items():
         for fe in sys_data.get("files", []):
             fe["_cores"] = sorted(fe.get("_cores", set()))
+            fe["_required_by"] = sorted(fe.get("_required_by", set()))
             fe["_source_refs"] = sorted(fe.get("_source_refs", set()))
         # Add per-system coverage
         cov = system_cores.get(sys_id, {})