fix: same bytes under two paths agree in slots

A data directory cache and a bios/ copy of one file were judged by path, so 56 bluemsx destinations on AmberELEC and EmuELEC read as contradicted.

scripts/slots.py

@@ -22,6 +22,7 @@ from typing import TYPE_CHECKING
 
 import nativemode
 from common import (
+    compute_hashes,
     platform_arg,
     archive_entry,
     build_zip_contents_index,
@@ -759,12 +760,18 @@ def find_collisions(
 def _satisfies(profile: Claim, platform: Claim, db: dict) -> bool:
     """Whether the two layers agree on what ships at this destination.
 
-    They agree when they resolve to the same file, when the platform's own
+    They agree when they resolve to the same bytes, when the platform's own
     hash list accepts the profile's file, or when the profile's accepts the
     platform's. A contradiction needs both lists to reject the other side.
     """
     if profile.local_path == platform.local_path:
         return True
+    # Two paths can hold one content: AmberELEC's bluemsx declarations
+    # resolve into the data/bluemsx cache, the profile's into bios/.
+    if profile.local_path and platform.local_path:
+        shipped = _content_sha1(platform.local_path, db)
+        if shipped is not None and shipped == _content_sha1(profile.local_path, db):
+            return True
     members = profile.entry.get("members")
     if members and platform.local_path:
         return holds_required_members(platform.local_path, members)
@@ -821,6 +828,19 @@ def _record_at(path: str, db: dict) -> dict | None:
 _PATH_INDEX: dict[int, tuple[dict, dict[str, dict]]] = {}
 
 
+def _content_sha1(path: str, db: dict) -> str | None:
+    """The sha1 of the file at path, from the database or read from disk.
+
+    A data directory cache is not in the database, so its files are hashed.
+    """
+    record = _record_at(path, db)
+    if record is not None:
+        return record.get("sha1")
+    if not os.path.isfile(path):
+        return None
+    return compute_hashes(path, frozenset({"sha1"}))["sha1"]
+
+
 def _accepted_by_all(path: str, entries: list[dict], db: dict) -> bool:
     """Whether every declaration's own hashes accept the file at path."""
     record = _record_at(path, db)

tests/test_slots.py

@@ -936,6 +936,32 @@ class ARecordIsFoundByItsPathOnce(unittest.TestCase):
         self.assertEqual(Counted.walks, 1)
 
 
+class TwoPathsHoldingOneContentAgree(unittest.TestCase):
+    """AmberELEC's bluemsx declarations resolve into the data/bluemsx cache,
+    the profile into bios/. Neither declares a hash and the bytes are the
+    same, yet the paths differed and 56 destinations read as contradicted."""
+
+    def test_same_bytes_under_two_paths_satisfy(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            cache = Path(tmp, "data", "MSX2EXT.rom")
+            stored = Path(tmp, "bios", "MSX2EXT.rom")
+            other = Path(tmp, "bios", "other.rom")
+            for path, payload in ((cache, b"rom"), (stored, b"rom"), (other, b"xyz")):
+                path.parent.mkdir(parents=True, exist_ok=True)
+                path.write_bytes(payload)
+            db = {"files": {}}
+            platform = Claim("platform", "Machines/MSX2EXT.rom", "MSX2EXT.rom",
+                             local_path=str(cache), status="path_exact")
+            same = Claim("profile", "Machines/MSX2EXT.rom", "MSX2EXT.rom",
+                         emulator="bluemsx", local_path=str(stored),
+                         status="path_exact")
+            different = Claim("profile", "Machines/MSX2EXT.rom", "MSX2EXT.rom",
+                              emulator="bluemsx", local_path=str(other),
+                              status="path_exact")
+            self.assertTrue(slots._satisfies(same, platform, db))
+            self.assertFalse(slots._satisfies(different, platform, db))
+
+
 class TheSlotsSummaryClosesTheRun(unittest.TestCase):
     """The totals came before the collision section and ignored it, and the
     help said the default run fails on conflicts the pack should settle,