Skip symlink files in zip command

CHANGELOG.md

@@ -1,5 +1,25 @@
 # Changelog
 
+## 7.0.0
+
+### Breaking Changes
+
+- **`datacustomcode zip` and `datacustomcode deploy` no longer package symlinks.**
+
+  Symlinks found inside the payload directory are skipped instead of being followed. A symlinked file logs a `Skipping symlink file <path>` warning and is left out of `deployment.zip`.
+
+  **Why:** Following a symlink packaged the bytes of its target into the archive, even when the target was outside the payload (for example `payload/notes.txt -> ~/.ssh/id_rsa`).
+
+  **Migration:** Replace any symlink in the payload with a real copy of the file or directory it points to:
+
+  ```bash
+  # Before
+  ln -s ../shared/helpers.py payload/helpers.py
+
+  # After
+  cp ../shared/helpers.py payload/helpers.py
+  ```
+
 ## 6.1.0
 
 ### Added

README.md

@@ -383,6 +383,8 @@ Options:
 #### `datacustomcode zip`
 Zip a transformation job in preparation to upload to Data Cloud. Make sure to change directory into your code package folder (e.g., `my_package`) before running this command.
 
+Symlinks inside the payload folder are not followed or packaged. Each symlinked file that is skipped is reported with a warning, and symlinked directories are not included. `datacustomcode deploy` zips the same way.
+
 Arguments:
 - `PATH`: Path to the code directory i.e. the payload folder (default: "payload")
 

src/datacustomcode/deploy.py

@@ -630,12 +630,15 @@ def zip(
     logger.debug(f"Zipping directory... {directory}")
 
     with zipfile.ZipFile(ZIP_FILE_NAME, "w", zipfile.ZIP_DEFLATED) as zipf:
-        for root, dirs, files in os.walk(directory):
-            # Skip .DS_Store and local credentials.
+        for root, dirs, files in os.walk(directory, followlinks=False):
+            # Skip symlinks, .DS_Store and local credentials.
             for file in files:
+                abs_path = os.path.join(root, file)
+                arcname = os.path.relpath(abs_path, directory)
+                if os.path.islink(abs_path):
+                    logger.warning(f"Skipping symlink file {arcname}")
+                    continue
                 if file not in EXCLUDED_FILES:
-                    abs_path = os.path.join(root, file)
-                    arcname = os.path.relpath(abs_path, directory)
                     zipf.write(abs_path, arcname)
 
     logger.debug(f"Created zip file: {ZIP_FILE_NAME}")

tests/test_deploy.py

@@ -841,6 +841,44 @@ def test_zip_excludes_ds_store_and_external_credentials(
         assert not any(".DS_Store" in path for path in written)
 
 
+class TestZipSymlinks:
+    """zip() must skip symlinked files instead of following them into the archive."""
+
+    @pytest.fixture
+    def mocks(self):
+        with (
+            patch(
+                "datacustomcode.deploy.has_nonempty_requirements_file",
+                return_value=False,
+            ),
+            patch("zipfile.ZipFile") as mock_zipfile,
+            patch("os.walk") as mock_walk,
+        ):
+            yield mock_walk, mock_zipfile.return_value.__enter__.return_value
+
+    def test_zip_skips_symlinked_files(self, mocks):
+        mock_walk, mock_zipfile_instance = mocks
+        mock_walk.return_value = [
+            ("/test/dir", ["subdir"], ["entrypoint.py", "linked.txt"]),
+            ("/test/dir/subdir", [], ["nested.py", "linked.py"]),
+        ]
+        links = {"/test/dir/linked.txt", "/test/dir/subdir/linked.py"}
+
+        with patch("os.path.islink", side_effect=lambda path: path in links):
+            zip("/test/dir", "default", "script")
+
+        written = [call.args[0] for call in mock_zipfile_instance.write.call_args_list]
+        assert written == ["/test/dir/entrypoint.py", "/test/dir/subdir/nested.py"]
+
+    def test_zip_skips_symlinked_directories(self, mocks):
+        mock_walk, _ = mocks
+        mock_walk.return_value = []
+
+        zip("/test/dir", "default", "script")
+
+        mock_walk.assert_called_once_with("/test/dir", followlinks=False)
+
+
 class TestUploadZip:
     @patch("datacustomcode.deploy.requests.put")
     @patch("builtins.open", new_callable=mock_open, read_data=b"test data")