fix: count bizhawk corrections only where it writes

scripts/exporter/bizhawk_exporter.py

@@ -60,6 +60,14 @@ class Exporter(BaseExporter):
         # hang off exist nowhere else.
         return True
 
+    def states(self, fe: NativeFile, field_name: str) -> bool:
+        """A name that resolves to several SHA1s is left alone, so its
+        correction is not a change the database receives."""
+        touchable = getattr(self, "_touchable", None)
+        if field_name == "sha1" and touchable is not None and fe.name.casefold() not in touchable:
+            return False
+        return super().states(fe, field_name)
+
     @staticmethod
     def _unambiguous(systems: dict[str, NativeSystem]) -> dict[str, NativeFile]:
         """Files whose name identifies exactly one entry with a SHA1.
@@ -96,6 +104,7 @@ class Exporter(BaseExporter):
             )
 
         index = self._unambiguous(systems)
+        self._touchable = set(index)
 
         def commented_out(text: str, position: int) -> bool:
             """Whether the call sits on a line the compiler never sees.

tests/test_export_counts.py

@@ -166,6 +166,21 @@ class EmuDeckWritesItsCorrections(unittest.TestCase):
         )
 
 
+class BizHawkCountsWhatItWrites(unittest.TestCase):
+    def test_an_ambiguous_name_is_not_counted(self):
+        from exporter.bizhawk_exporter import Exporter as BizHawk
+
+        sha_a, sha_b, sha_c = "a" * 40, "b" * 40, "c" * 40
+        first = NativeFile("bios.bin", "bios.bin", "S1", platform={"sha1": sha_a},
+                           truth={"sha1": sha_b}, corrections=["sha1"])
+        second = NativeFile("bios.bin", "bios.bin", "S2", platform={"sha1": sha_c})
+        systems = {"S1": NativeSystem("S1", files=[first]), "S2": NativeSystem("S2", files=[second])}
+        exporter = BizHawk()
+        source = f'File("{sha_a.upper()}", 16, "bios.bin")\n'
+        exporter.render(systems, None, {exporter.native_filename(): source})
+        self.assertFalse(exporter.states(first, "sha1"))
+
+
 class ModelKeepsOneFileOneEntry(unittest.TestCase):
     def test_size_describes_the_hash_written(self):
         fe = NativeFile("boot.bin", "dc/boot.bin", "dc",