fix: withhold a file only on the frontend digest

scripts/generate_pack.py

@@ -75,6 +75,7 @@ from nativemode import (
 )
 from validation import (
     agnostic_substitute,
+    frontend_digest_matches,
     _build_validation_index,
     check_file_validation,
     filter_files_by_mode,
@@ -885,6 +886,11 @@ def generate_pack(
                             )
                         if not zip_ok:
                             continue
+                    elif frontend_digest_matches(
+                        file_entry, local_path, digest_algorithm(verification_mode)
+                    ):
+                        status = "frontend_digest_exact"
+                        file_status.setdefault(dedup_key, "ok")
                     else:
                         file_status[dedup_key] = "excluded"
                         file_reasons[dedup_key] = "hash mismatch"
@@ -3108,6 +3114,16 @@ def generate_manifest(
                     and _inner_rom_check(file_entry, local_path) == "ok"
                 ):
                     status = "zip_exact"
+                if (
+                    status == "hash_mismatch"
+                    and local_path
+                    and not file_entry.get("zipped_file")
+                    and hash_mismatch_excludes_file(verification_mode)
+                    and frontend_digest_matches(
+                        file_entry, local_path, digest_algorithm(verification_mode)
+                    )
+                ):
+                    status = "frontend_digest_exact"
                 # An existence platform never reads the bytes, so a declared
                 # hash the local dump contradicts is not a reason to withhold
                 # the file. Hash platforms would reject it, so they omit it.

scripts/packverify.py

@@ -17,6 +17,7 @@ from packpaths import _register_path
 from ziptools import build_zip_contents_index
 from ziptools import check_inside_zip
 from nativemode import digest_algorithm
+from validation import frontend_digest_matches
 from nativemode import hash_mismatch_excludes_file
 import hashlib
 from common import filter_systems_by_target
@@ -406,6 +407,11 @@ def _intentional_hash_exclusion(
         )
         if status != "hash_mismatch":
             return False
+        if not entry.get("zipped_file") and frontend_digest_matches(
+            entry, local_path, digest_algorithm(verification_mode)
+        ):
+            # The frontend's own digest accepts it: the builder ships it.
+            return False
 
         # A container can mismatch the outer declaration while still carrying
         # the exact inner ROM requested by Batocera-style zipped_file entries.

scripts/validation.py

@@ -431,3 +431,22 @@ def agnostic_substitute(
                         return held, prefix
                 break
     return None
+
+
+def frontend_digest_matches(file_entry: dict, local_path: str, algorithm: str) -> bool:
+    """Whether the frontend's own digest accepts the file.
+
+    resolve_local_file calls a file `hash_mismatch` when any declared hash
+    disagrees, but a frontend compares one digest. RomM's list carries md5,
+    sha1 and crc32: a mistyped crc32 next to the right md5 must not withhold
+    a file RomM accepts. Same comparison as verify_entry_md5/_sha1.
+    """
+    if algorithm == "md5":
+        declared = parse_md5_list(file_entry.get("md5"))
+    else:
+        value = file_entry.get(algorithm)
+        values = value if isinstance(value, list) else [value]
+        declared = [str(v).strip().lower() for v in values if v]
+    if not declared or not local_path:
+        return False
+    return compute_hashes(local_path)[algorithm].lower() in declared

tests/test_frontend_digest.py

@@ -0,0 +1,89 @@
+"""A digest frontend withholds a file only when ITS digest disagrees.
+
+RomM's list declares md5, sha1 and crc32 per file and RomM accepts any of
+them. The resolver calls a file `hash_mismatch` when any declared hash
+disagrees, so a mistyped crc32 beside the right md5 dropped the file from
+the pack and the manifest while verify, comparing md5, called it OK.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import json
+import os
+import sys
+import tempfile
+import unittest
+import zipfile
+from pathlib import Path
+
+import yaml
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(REPO_ROOT / "scripts"))
+
+
+class FrontendDigestDecides(unittest.TestCase):
+    def setUp(self):
+        (REPO_ROOT / "tmp").mkdir(exist_ok=True)
+        self.tmp = tempfile.TemporaryDirectory(dir=REPO_ROOT / "tmp")
+        self.addCleanup(self.tmp.cleanup)
+        root = Path(self.tmp.name)
+        self.bios = root / "bios"
+        self.bios.mkdir()
+        payload = b"psx bios " * 64
+        held = self.bios / "scph5501.bin"
+        held.write_bytes(payload)
+        md5 = hashlib.md5(payload).hexdigest()
+        sha1 = hashlib.sha1(payload).hexdigest()
+        self.platforms = root / "platforms"
+        self.platforms.mkdir()
+        (root / "emulators").mkdir()
+        self.emulators = root / "emulators"
+        (self.platforms / "_registry.yml").write_text(
+            yaml.safe_dump({"platforms": {"digestplat": {"status": "active"}}})
+        )
+        (self.platforms / "digestplat.yml").write_text(yaml.safe_dump({
+            "platform": "DigestPlat",
+            "verification_mode": "md5",
+            "base_destination": "bios",
+            "systems": {"psx": {"files": [{
+                "name": "scph5501.bin", "destination": "scph5501.bin",
+                "md5": md5, "crc32": "00000000", "required": True,
+            }]}},
+        }))
+        self.db = {
+            "files": {sha1: {"path": str(held), "name": "scph5501.bin", "size": len(payload),
+                             "sha1": sha1, "md5": md5, "crc32": "deadbeef"}},
+            "indexes": {"by_md5": {md5: sha1}, "by_name": {"scph5501.bin": [sha1]},
+                        "by_crc32": {}, "by_path_suffix": {}},
+        }
+        self.root = root
+
+    def test_pack_manifest_and_verify_agree(self):
+        from common import load_platform_config
+        from generate_pack import generate_manifest, generate_pack
+        from verify import verify_platform
+
+        os.chdir(self.root)
+        self.addCleanup(os.chdir, REPO_ROOT)
+        zip_path = generate_pack(
+            "digestplat", str(self.platforms), self.db, str(self.bios),
+            str(self.root / "out"), emulators_dir=str(self.emulators),
+            emu_profiles={}, offline=True,
+        )
+        with zipfile.ZipFile(zip_path) as zf:
+            self.assertIn("scph5501.bin", {Path(n).name for n in zf.namelist()})
+        manifest = generate_manifest(
+            "digestplat", str(self.platforms), self.db, str(self.bios),
+            str(self.platforms / "_registry.yml"), emulators_dir=str(self.emulators),
+            emu_profiles={}, offline=True,
+        )
+        self.assertEqual([f["dest"] for f in manifest["files"]], ["scph5501.bin"])
+        config = load_platform_config("digestplat", str(self.platforms))
+        result = verify_platform(config, self.db, str(self.emulators), emu_profiles={})
+        self.assertEqual(result["details"][0]["status"], "ok")
+
+
+if __name__ == "__main__":
+    unittest.main()