Expose symlinks option for updates on macOS (#148)

* expose shutil.copytree symlinks argument in _install_update_mac

* test that symlinks arg is properly passed

src/tufup/repo/__init__.py

@@ -953,6 +953,7 @@ def threshold_sign(
 
     def _load_keys_and_roles(self, create_keys: bool = False):
         # todo: make public, rename load_keys_and_metadata
+        # todo: check import success (now says "metadata imported" even if files not found)
         if self.keys is None:
             logger.info('Importing public keys...')
             self.keys = Keys(

src/tufup/utils/platform_specific.py

@@ -239,8 +239,14 @@ def _install_update_mac(
     dst_dir: Union[pathlib.Path, str],
     purge_dst_dir: bool,
     exclude_from_purge: List[Union[pathlib.Path, str]],
+    symlinks: bool = False,
     **kwargs,
 ):
+    """
+    The symlinks arg is passed on to shutil.copytree()
+
+    [1]: https://docs.python.org/3/library/shutil.html#shutil.copytree
+    """
     # todo: implement as_admin and debug kwargs for mac
     logger.debug(f'Kwargs not used: {kwargs}')
     if purge_dst_dir:
@@ -256,7 +262,7 @@ def _install_update_mac(
             if path not in exclude_from_purge:
                 remove_path(path=path)
     logger.debug(f'Moving content of {src_dir} to {dst_dir}.')
-    shutil.copytree(src_dir, dst_dir, dirs_exist_ok=True)
+    shutil.copytree(src_dir, dst_dir, dirs_exist_ok=True, symlinks=symlinks)
     # Note: the src_dir is typically a temporary directory, but we'll clear
     # it anyway just to be consistent with the windows implementation
     for path in pathlib.Path(src_dir).iterdir():

tests/test_utils_platform_specific.py

@@ -7,9 +7,12 @@
 import textwrap
 from time import sleep
 import unittest
+from unittest.mock import patch
 
 from tests import BASE_DIR, TempDirTestCase
+import tufup.utils.platform_specific as ps
 from tufup.utils.platform_specific import (
+    ON_MAC,
     ON_WINDOWS,
     PLATFORM_SUPPORTED,
     run_bat_as_admin,
@@ -91,6 +94,14 @@ def test_run_bat_as_admin(self):
         self.assertTrue(len(output))
         self.assertNotIn(current_user, output)
 
+    @unittest.skipIf(condition=not ON_MAC, reason='macOS only')
+    def test_install_update_macos_symlinks(self):
+        with patch.object(ps, '_install_update_mac') as mock_install_update_mac:
+            ps.install_update(src_dir='', dst_dir='')
+            self.assertNotIn('symlinks', mock_install_update_mac.call_args.kwargs)
+            ps.install_update(src_dir='', dst_dir='', symlinks=True)
+            self.assertTrue(mock_install_update_mac.call_args.kwargs['symlinks'])
+
     @unittest.skipIf(
         condition=not PLATFORM_SUPPORTED, reason=_reason_platform_not_supported
     )