fix: keep tree entries out of the asset store

scripts/largefiles.py

@@ -126,6 +126,10 @@ def fetch_large_file(
     turns it into the asset to fetch, and a bare name shared by several
     registered paths tries each of their assets until one verifies.
     """
+    if not name or name.endswith("/"):
+        # A directory entry names a tree, never one asset: asked for
+        # "caesar3/", the store answered with .cache/large/ itself.
+        return None
     if registered is None:
         registered = load_registered_paths()
     for asset in asset_candidates(name, registered):
@@ -153,6 +157,8 @@ def _fetch_asset(
         with contextlib.suppress(FileNotFoundError):
             os.unlink(path)
 
+    if os.path.isdir(cached):
+        return None
     if os.path.exists(cached):
         try:
             hashes = compute_hashes(cached) if (expected_sha1 or expected_md5) else {}

scripts/packresolve.py

@@ -210,6 +210,10 @@ def resolve_file(
     # Large files from GitHub release assets -tried when local file is
     # missing OR has a hash mismatch (wrong variant on disk)
     name = file_entry.get("name", "")
+    if file_entry.get("type") == "directory" or name.endswith("/"):
+        # A tree the collection does not hold is missing, as verify says;
+        # the asset store holds files, not trees.
+        return (path, status) if path else (None, "not_found")
     declared = _declared_hashes(file_entry)
     if file_entry.get("unsourceable") and not any(declared.values()):
         # The asset store is addressed by file name: with no hash to check,

tests/test_audit_regressions.py

@@ -3780,5 +3780,28 @@ class SignaturesCarryTheirTypes(unittest.TestCase):
                 self.assertEqual(self._missing(ROOT / "scripts" / name), [])
 
 
+
+class ATreeNobodyHoldsIsMissingNotAnAsset(unittest.TestCase):
+    """julius's caesar3/ directory, unexpanded, went to the asset store,
+    which answered with .cache/large/ itself: the emulator pack died on
+    IsADirectoryError where verify said MISSING."""
+
+    def test_directory_entries_never_reach_the_asset_store(self):
+        from scripts import largefiles, packresolve
+
+        db = {"files": {}, "indexes": {"by_name": {}, "by_md5": {}, "by_crc32": {},
+                                      "by_path_suffix": {}}}
+        for entry in ({"name": "caesar3/", "type": "directory"}, {"name": "caesar3/"}):
+            with self.subTest(entry=entry):
+                self.assertEqual(
+                    packresolve.resolve_file(entry, db, "bios", {}, offline=True),
+                    (None, "not_found"),
+                )
+        self.assertIsNone(largefiles.fetch_large_file("caesar3/", offline=True))
+        with tempfile.TemporaryDirectory(dir=TMP_ROOT) as tmp:
+            Path(tmp, "sub").mkdir()
+            self.assertIsNone(largefiles._fetch_asset("sub", tmp, "", "", offline=True))
+
+
 if __name__ == "__main__":
     unittest.main()