fix: make file ordering deterministic

Author: ajaxbits

package_python_function/packager.py

@@ -46,7 +46,8 @@ def zip_all_dependencies(self, target_path: Path) -> None:
 
         with ZipFile(target_path, "w", ZIP_DEFLATED) as zip_file:
             def zip_dir(path: Path) -> None:
-                for item in path.iterdir():
+                # use sorted to make sure files are always written in a deterministic order
+                for item in sorted(path.iterdir(), key=lambda i: i.name):
                     if item.is_dir():
                         if item.name not in self.DIRS_TO_EXCLUDE:
                             zip_dir(item)

tests/test_determinism.py

@@ -72,6 +72,29 @@ def test_package_python_function(
             else:
                 assert (verify_dir / file.path).exists()
 
+def test_python_package_deterministic_file_ordering(
+    test_data: Data,
+    tmp_path: Path,
+):
+    zip_contents: dict[str, list[str]] = {}
+    for id in ["a", "b"]:
+        output = tmp_path / f"output_{id}"
+        output.mkdir()
+        sys.argv = [
+            "test_package_python_function",
+            str(test_data.venv_dir),
+            "--project",
+            str(test_data.pyproject.path),
+            "--output-dir",
+            str(output),
+        ]
+        main()
+        zip_file = output / f"{test_data.pyproject.name.replace('-', '_')}.zip"
+        with zipfile.ZipFile(zip_file, "r") as zip_file:
+            zip_contents[id] = list(map(lambda zi: zi.filename, zip_file.infolist()))
+
+    assert zip_contents["a"] == zip_contents["b"], "File ordering in the zip file is not deterministic across runs."
+
 @pytest.mark.parametrize(
     "src_epoch, expected_exception, expected_date_time",
     [