From 5e955741432dee1f11784900c561ce4ab7feb8b9 Mon Sep 17 00:00:00 2001
From: Abdessamad Derraz <3028866+Abdess@users.noreply.github.com>
Date: Wed, 21 Oct 2026 05:28:10 +0200
Subject: [PATCH] fix: the strongest proof takes a shared core path

A destination no platform declares went to the first claimant in profile
order whatever the proof: fbalpha2012 asks for hiscore.dat by name and
took the root of six packs over cores that pin it by sha1. Claims on a
contested path are now ranked by what the collection holds for each (a
held declared hash, then a path or every required archive member, then a
name, then a contradicted hash), and profile order only breaks ties.
Measured: 14 slots change file across the platforms, among them
hiscore.dat, kick13.rom on RetroPie, cgb_boot.bin and dmg_boot.bin on
EmuDeck, and ROCKNIX neogeo.zip and neocdz.zip.
---
 scripts/packextras.py | 90 +++++++++++++++++++++++++++++++++++++------
 tests/test_slots.py   | 25 ++++++++++++
 2 files changed, 104 insertions(+), 11 deletions(-)

diff --git a/scripts/packextras.py b/scripts/packextras.py
index 739be271..6a2b2d02 100644
--- a/scripts/packextras.py
+++ b/scripts/packextras.py
@@ -9,7 +9,7 @@ from __future__ import annotations
 from collections.abc import Iterable
 
 from common import PROFILE_IDENTITY_FIELDS, _norm_system_id
-from common import archive_members
+from common import archive_members, holds_required_members
 from common import declared_root, expand_platform_declared_names, platform_declarations
 from common import load_emulator_profiles
 from common import resolution_is_hash_exact
@@ -863,11 +863,16 @@ def _collect_emulator_extras(
             config, emulators_dir, db, emu_profiles, target_cores=target_cores,
             include_all=include_all, declared_names=yaml_names,
         )
-    # A destination two cores claim goes to the one that names its content:
+    # A destination two cores claim goes to the strongest proof of what the
+    # collection holds for it, then to the one that names its content:
     # hypseus-singe asks for gamecontrollerdb.txt by name alone and took the
-    # BIOS root before Solarus, which pins its own by sha1. Profile order
-    # still decides between claims of the same kind.
-    undeclared = sorted(undeclared, key=lambda u: not _names_content(u))
+    # BIOS root before Solarus, which pins its own by sha1, and fbalpha2012's
+    # hashless hiscore.dat took RetroDECK's over mame2015's sha1. Profile
+    # order decides only between claims of equal proof.
+    rank = _ClaimRanks(undeclared, placement, db)
+    undeclared = sorted(
+        undeclared, key=lambda u: (-rank.of_entry(u), not _names_content(u))
+    )
     extras = []
     seen_dests: set[str] = set(seen)
     # Destination -> the extra that took it, to record later claimants on.
@@ -906,12 +911,18 @@ def _collect_emulator_extras(
             claimants[(u.get("emulator", ""), u.get("name", ""), u.get("path") or "")] = (
                 sanitize_pack_path(dest)
             )
-        extra = _report_extra(u, name, dest)
-        claims = [_report_extra(c, name, dest) for c in u.get("other_claims", [])]
-        # Where the builder meets each claim: the report lists the profiles in
-        # order, archives after the loose files.
-        for item in (extra, *claims):
-            item["claim_order"] = (1, 1 if u.get("archive") else 0, item["source_profile"])
+        candidates = [
+            _report_extra(c, name, dest) for c in (u, *u.get("other_claims", []))
+        ]
+        # Where the builder meets each claim: the strongest proof first, the
+        # report's profile order between equals, archives after loose files.
+        for item in candidates:
+            item["claim_order"] = (
+                1, 1 if u.get("archive") else 0, -rank.of_extra(item, full_dest),
+                item["source_profile"],
+            )
+        candidates.sort(key=lambda item: item["claim_order"])
+        extra, claims = candidates[0], candidates[1:]
         if not _take(extra, full_dest, seen_dests, taken):
             for claim in claims:
                 _another_claim(taken.get(full_dest), claim)
@@ -1036,6 +1047,63 @@ def _collect_emulator_extras(
 
     return extras
 
+class _ClaimRanks:
+    """How strongly each claim on a contested destination proves its file.
+
+    2 a declared hash the collection holds, 1 a path or every member the
+    core requires inside an archive, 0 a name, -1 a copy
+    contradicting the hash the claim declares, -2 nothing held. Resolved only
+    where two claims meet: a destination one core asks for has no contest.
+    """
+
+    def __init__(self, undeclared: list[dict], placement: ExtraPlacement, db: dict) -> None:
+        self._db = db
+        self._placed: dict[int, tuple[str, str] | None] = {}
+        counts: dict[str, int] = {}
+        for u in undeclared:
+            placed = (
+                placement.place(u, _extra_dest(u))
+                if u.get("in_repo") and not u.get("bundled") else None
+            )
+            self._placed[id(u)] = placed
+            if placed is not None:
+                counts[placed[1]] = counts.get(placed[1], 0) + 1 + len(
+                    u.get("other_claims", [])
+                )
+        self._contested = {dest for dest, n in counts.items() if n > 1}
+        self._cache: dict[tuple, int] = {}
+
+    def of_extra(self, extra: dict, full_dest: str) -> int:
+        if full_dest not in self._contested:
+            return 0
+        key = (extra.get("source_profile"), extra.get("source_name"),
+               extra.get("source_path"), full_dest)
+        if key not in self._cache:
+            path, status = resolve_local_file(
+                extra, self._db, dest_hint=extra.get("destination", "")
+            )
+            self._cache[key] = (
+                -2 if not path
+                else -1 if status == "hash_mismatch"
+                else 2 if resolution_is_hash_exact(status)
+                else 1 if status == "path_exact" or (
+                    extra.get("members") and holds_required_members(path, extra["members"])
+                )
+                else 0
+            )
+        return self._cache[key]
+
+    def of_entry(self, u: dict) -> int:
+        placed = self._placed.get(id(u))
+        if placed is None or placed[1] not in self._contested:
+            return 0
+        name = u.get("archive") or u["name"]
+        return max(
+            self.of_extra(_report_extra(c, name, placed[0]), placed[1])
+            for c in (u, *u.get("other_claims", []))
+        )
+
+
 def _names_content(entry: dict) -> bool:
     """Whether a report entry declares the bytes it wants, not only a name."""
     return any(entry.get(field) for field in ("sha1", "md5", "sha256", "crc32"))
diff --git a/tests/test_slots.py b/tests/test_slots.py
index 825ee5aa..d5444995 100644
--- a/tests/test_slots.py
+++ b/tests/test_slots.py
@@ -418,6 +418,31 @@ class TestArbitration(unittest.TestCase):
         self.assertIn("both are satisfied", served)
 
 
+class TheStrongestProofTakesAnUndeclaredPath(unittest.TestCase):
+    """No platform declares RetroDECK's hiscore.dat. fbalpha2012 asks for it
+    by name, mame2015 pins it by sha1: the first in profile order took the
+    path, whatever the proof, and mame2015 received another revision."""
+
+    def test_a_held_hash_beats_a_bare_name_whatever_the_order(self):
+        from packextras import _collect_emulator_extras
+
+        config = {
+            "platform": "P", "verification_mode": "existence",
+            "cores": ["aaa", "zzz"],
+            "systems": {"console": {"files": [{"name": "other.bin", "destination": "other.bin"}]}},
+        }
+        profiles = {
+            "aaa": {"emulator": "Aaa", "type": "libretro", "systems": ["console"],
+                    "files": [{"name": "IPL.bin", "required": True}]},
+            "zzz": {"emulator": "Zzz", "type": "libretro", "systems": ["console"],
+                    "files": [{"name": "IPL.bin", "required": True, "md5": "n" * 32}]},
+        }
+        extras = _collect_emulator_extras(config, "", REGIONS_DB, set(), "", profiles)
+        winner = next(e for e in extras if e["destination"] == "IPL.bin")
+        self.assertEqual(winner["source_profile"], "zzz")
+        self.assertEqual({c["source_profile"] for c in winner["other_claims"]}, {"aaa"})
+
+
 class TestBuilderAndVerifierAgree(unittest.TestCase):
     """The two tools must settle a contested destination the same way."""