fix: suggest the database beside a mistyped --db

--db databse.json, with database.json in the same folder, was told to run
generate_db --force --output databse.json: a rescan of the whole
collection into a second file under the typo. load_database now names the
closest .json in that folder first, and gives the rebuild command only
when none is close.

scripts/common.py

@@ -73,6 +73,18 @@ def load_database(db_path: str) -> dict:
         with open(db_path) as f:
             return json.load(f)
     except FileNotFoundError:
+        # A mistyped --db beside the real database was told to rescan the
+        # whole collection into a second file under the typo.
+        import difflib  # noqa: PLC0415
+
+        typed = Path(db_path)
+        close = difflib.get_close_matches(
+            typed.name, [p.name for p in typed.parent.glob("*.json")], n=1, cutoff=0.8
+        )
+        if close:
+            raise DatabaseUnreadable(
+                f"{db_path} not found. Did you mean {typed.with_name(close[0])}?"
+            ) from None
         raise DatabaseUnreadable(
             f"{db_path} not found. Build it with: python scripts/generate_db.py "
             f"--force --bios-dir bios --output {db_path}"

tests/test_audit_regressions.py

@@ -6060,6 +6060,20 @@ class TheRepairCommandWritesTheFileNamed(unittest.TestCase):
                 load_database(target)
             self.assertIn(f"--output {target}", str(caught.exception))
 
+    def test_a_typo_beside_the_database_names_the_database(self):
+        """--db databse.json beside database.json was told to rescan the whole
+        collection into a second file named after the typo."""
+        from scripts.common import DatabaseUnreadable, load_database
+
+        with tempfile.TemporaryDirectory(dir=TMP_ROOT) as directory:
+            (Path(directory) / "database.json").write_text("{}")
+            typo = Path(directory) / "databse.json"
+            with self.assertRaises(DatabaseUnreadable) as caught:
+                load_database(str(typo))
+        message = str(caught.exception)
+        self.assertIn(f"Did you mean {typo.with_name('database.json')}?", message)
+        self.assertNotIn("generate_db.py", message)
+
 
 class VerifyPacksRefusesWhatItCannotDo(unittest.TestCase):
     """The --verify-packs refusals lived in the --all-variants checks, which