From 24a5acce5d4e926d3758ea02b2a425e03258dff2 Mon Sep 17 00:00:00 2001
From: Georges-Antoine Assi <contact@me.gantoine.com>
Date: Sat, 18 Oct 2025 18:05:57 -0400
Subject: [PATCH] [ROMM-2552] Rom hashes should only include top-level nested
 files

---
 backend/handler/filesystem/roms_handler.py    | 27 ++++++--
 .../roms/Sonic (EU) [T]/Sonic (EU) [T].n64    |  1 +
 .../translation/Sonic (EU) [T-En].z64         |  1 +
 .../handler/filesystem/test_roms_handler.py   | 66 +++++++++++++++++++
 4 files changed, 88 insertions(+), 7 deletions(-)
 create mode 100644 backend/romm_test/library/n64/roms/Sonic (EU) [T]/Sonic (EU) [T].n64
 create mode 100644 backend/romm_test/library/n64/roms/Sonic (EU) [T]/translation/Sonic (EU) [T-En].z64

diff --git a/backend/handler/filesystem/roms_handler.py b/backend/handler/filesystem/roms_handler.py
index 519d150f6..ae5c7621d 100644
--- a/backend/handler/filesystem/roms_handler.py
+++ b/backend/handler/filesystem/roms_handler.py
@@ -330,16 +330,29 @@ class FSRomsHandler(FSHandler):
                 ):
                     continue
 
+                # Check if this is a top-level file (not in a subdirectory)
+                is_top_level = f_path.samefile(Path(abs_fs_path, rom.fs_name))
+
                 if hashable_platform:
                     try:
-                        crc_c, rom_crc_c, md5_h, rom_md5_h, sha1_h, rom_sha1_h = (
-                            self._calculate_rom_hashes(
-                                Path(f_path, file_name),
-                                rom_crc_c,
-                                rom_md5_h,
-                                rom_sha1_h,
+                        if is_top_level:
+                            # Include this file in the main ROM hash calculation
+                            crc_c, rom_crc_c, md5_h, rom_md5_h, sha1_h, rom_sha1_h = (
+                                self._calculate_rom_hashes(
+                                    Path(f_path, file_name),
+                                    rom_crc_c,
+                                    rom_md5_h,
+                                    rom_sha1_h,
+                                )
+                            )
+                        else:
+                            # Calculate individual file hash only
+                            crc_c, _, md5_h, _, sha1_h, _ = self._calculate_rom_hashes(
+                                Path(f_path, file_name),
+                                0,
+                                hashlib.md5(usedforsecurity=False),
+                                hashlib.sha1(usedforsecurity=False),
                             )
-                        )
                     except zlib.error:
                         crc_c = 0
                         md5_h = hashlib.md5(usedforsecurity=False)
diff --git a/backend/romm_test/library/n64/roms/Sonic (EU) [T]/Sonic (EU) [T].n64 b/backend/romm_test/library/n64/roms/Sonic (EU) [T]/Sonic (EU) [T].n64
new file mode 100644
index 000000000..5b290d000
--- /dev/null
+++ b/backend/romm_test/library/n64/roms/Sonic (EU) [T]/Sonic (EU) [T].n64	
@@ -0,0 +1 @@
+00000000
diff --git a/backend/romm_test/library/n64/roms/Sonic (EU) [T]/translation/Sonic (EU) [T-En].z64 b/backend/romm_test/library/n64/roms/Sonic (EU) [T]/translation/Sonic (EU) [T-En].z64
new file mode 100644
index 000000000..ca028fbba
--- /dev/null
+++ b/backend/romm_test/library/n64/roms/Sonic (EU) [T]/translation/Sonic (EU) [T-En].z64	
@@ -0,0 +1 @@
+11111111
diff --git a/backend/tests/handler/filesystem/test_roms_handler.py b/backend/tests/handler/filesystem/test_roms_handler.py
index 0e22d00b6..28363c803 100644
--- a/backend/tests/handler/filesystem/test_roms_handler.py
+++ b/backend/tests/handler/filesystem/test_roms_handler.py
@@ -46,6 +46,28 @@ class TestFSRomsHandler:
             full_path="n64/roms/Paper Mario (USA).z64",
         )
 
+    @pytest.fixture
+    def rom_single_nested(self, platform: Platform):
+        return Rom(
+            id=3,
+            fs_name="Sonic (EU) [T]",
+            fs_path="n64/roms",
+            platform=platform,
+            full_path="n64/roms/Sonic (EU) [T]",
+            files=[
+                RomFile(
+                    id=1,
+                    file_name="Sonic (EU) [T].n64",
+                    file_path="n64/roms",
+                ),
+                RomFile(
+                    id=2,
+                    file_name="Sonic (EU) [T-En].z64",
+                    file_path="n64/roms/translation",
+                ),
+            ],
+        )
+
     @pytest.fixture
     def rom_multi(self, platform: Platform):
         return Rom(
@@ -555,3 +577,47 @@ class TestFSRomsHandler:
         async with await handler.stream_file("psx/roms/PaRappa the Rapper.zip") as f:
             content = await f.read()
             assert len(content) > 0
+
+    async def test_top_level_files_only_in_main_hash(
+        self, handler: FSRomsHandler, rom_single_nested
+    ):
+        """Test that only top-level files contribute to main ROM hash calculation"""
+        rom_files, rom_crc, rom_md5, rom_sha1, rom_ra = await handler.get_rom_files(
+            rom_single_nested
+        )
+
+        # Verify we have multiple files (base game + translation)
+        assert len(rom_files) == 2
+
+        base_game_rom_file = None
+        translation_rom_file = None
+
+        for rom_file in rom_files:
+            if rom_file.file_name == "Sonic (EU) [T].n64":
+                base_game_rom_file = rom_file
+            elif rom_file.file_name == "Sonic (EU) [T-En].z64":
+                translation_rom_file = rom_file
+
+        assert base_game_rom_file is not None, "Base game file not found"
+        assert translation_rom_file is not None, "Translation file not found"
+
+        # Verify file categories
+        assert base_game_rom_file.category is None
+        assert translation_rom_file.category == RomFileCategory.TRANSLATION
+
+        # The main ROM hash should be different from the translation file hash
+        # (this verifies that the translation is not included in the main hash)
+
+        assert (
+            rom_md5 == base_game_rom_file.md5_hash
+        ), "Main ROM hash should include base game file"
+        assert (
+            rom_md5 != translation_rom_file.md5_hash
+        ), "Main ROM hash should not include translation file"
+
+        assert (
+            rom_sha1 == base_game_rom_file.sha1_hash
+        ), "Main ROM hash should include base game file"
+        assert (
+            rom_sha1 != translation_rom_file.sha1_hash
+        ), "Main ROM hash should not include translation file"