Fix: Start Lightning App on Cloud if Repo Begins With Name "Lightning" (#14025)

(cherry picked from commit b4ade23)

Author: rlizzo

src/lightning_app/utilities/packaging/lightning_utils.py

@@ -89,8 +89,13 @@ def get_dist_path_if_editable_install(project_name) -> str:
 
 
 def _prepare_lightning_wheels_and_requirements(root: Path) -> Optional[Callable]:
+    """This function determines if lightning is installed in editable mode (for developers) and packages the
+    current lightning source along with the app.
 
-    if "site-packages" in _PROJECT_ROOT:
+    For normal users who install via PyPi or Conda, then this function does not do anything.
+    """
+
+    if not get_dist_path_if_editable_install("lightning"):
         return
 
     # Packaging the Lightning codebase happens only inside the `lightning` repo.

tests/tests_app/utilities/packaging/test_lightning_utils.py

@@ -1,4 +1,5 @@
 import os
+from unittest import mock
 
 import pytest
 
@@ -21,6 +22,21 @@ def test_prepare_lightning_wheels_and_requirement(tmpdir):
     assert os.listdir(tmpdir) == []
 
 
+def _mocked_get_dist_path_if_editable_install(*args, **kwargs):
+    return None
+
+
+@mock.patch(
+    "lightning_app.utilities.packaging.lightning_utils.get_dist_path_if_editable_install",
+    new=_mocked_get_dist_path_if_editable_install,
+)
+def test_prepare_lightning_wheels_and_requirement_for_packages_installed_in_editable_mode(tmpdir):
+    """This test ensures the source does not get packaged inside the lightning repo if not installed in editable
+    mode."""
+    cleanup_handle = _prepare_lightning_wheels_and_requirements(tmpdir)
+    assert cleanup_handle is None
+
+
 @pytest.mark.skip(reason="TODO: Find a way to check for the latest version")
 @RunIf(skip_windows=True)
 def test_verify_lightning_version(monkeypatch):