Fix LK build path for catalyst shared library (#968)

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------------------------------------------------------------------------------------------------------------

**Context:**
This PR fixes Lightning Kokkos with Catalyst failing due to wrong build
path supplied to `setup.py` and lightning kokkos in editable mode.

**Description of the Change:**

**Benefits:**

**Possible Drawbacks:**

**Related GitHub Issues:**

[sc-77123]

.github/CHANGELOG.md

@@ -131,6 +131,9 @@
 
 ### Bug fixes
 
+*  Fix `liblightning_kokkos_catalyst.so` not copied to correct build path for editable installation.
+  [(#968)](https://github.com/PennyLaneAI/pennylane-lightning/pull/968)
+
 *  Fix PTM stable latest related to `default.qubit.legacy`. 
   [(#966)](https://github.com/PennyLaneAI/pennylane-lightning/pull/966)
 
@@ -156,7 +159,7 @@
 
 This release contains contributions from (in alphabetical order):
 
-Ali Asadi, Amintor Dusko, Luis Alfredo Nuñez Meneses, Vincent Michaud-Rioux, Lee J. O'Riordan, Mudit Pandey, Shuli Shu, Haochen Paul Wang
+Ali Asadi, Amintor Dusko, Joseph Lee, Luis Alfredo Nuñez Meneses, Vincent Michaud-Rioux, Lee J. O'Riordan, Mudit Pandey, Shuli Shu, Haochen Paul Wang
 
 ---
 

.github/workflows/tests_lkcpu_python.yml

@@ -264,6 +264,17 @@ jobs:
           pl-device-test --device ${DEVICENAME} --shots=None --skip-ops $COVERAGE_FLAGS --cov-append
           mv .coverage ${{ github.workspace }}/.coverage-${{ github.job }}-${{ matrix.pl_backend }}-${{ matrix.group }}
 
+      - name: Test editable install
+        run: |
+          rm -r build
+          pip uninstall pennylane-lightning pennylane-lightning-kokkos -y
+          python scripts/configure_pyproject_toml.py
+          SKIP_COMPILATION=True python -m pip install -e . --config-settings editable_mode=compat
+          DEVICENAME=`echo ${{ matrix.pl_backend }} | sed "s/_/./g"`
+          PL_BACKEND=${DEVICENAME} python scripts/configure_pyproject_toml.py
+          python -m pip install -e . --config-settings editable_mode=compat -vv
+          PL_DEVICE=${DEVICENAME} python -m pytest tests/test_device.py $COVERAGE_FLAGS
+
       - name: Upload test durations
         uses: actions/upload-artifact@v4
         with:

pennylane_lightning/lightning_kokkos/lightning_kokkos.py

@@ -534,7 +534,7 @@ def get_c_interface():
         #   lib.<system>-<architecture>-<python-id>"
         # To avoid mismatching the folder name, we search for the shared object instead.
         # TODO: locate where the naming convention of the folder is decided and replicate it here.
-        editable_mode_path = package_root.parent.parent / "build"
+        editable_mode_path = package_root.parent.parent / "build_lightning_kokkos"
         for path, _, files in os.walk(editable_mode_path):
             if lib_name in files:
                 lib_location = (Path(path) / lib_name).as_posix()

setup.py

@@ -161,7 +161,7 @@ def build_extension(self, ext: CMakeExtension):
             if platform.system() in ["Linux", "Darwin"]:
                 shared_lib_ext = {"Linux": ".so", "Darwin": ".dylib"}[platform.system()]
                 source = os.path.join(f"{extdir}", f"lib{backend}_catalyst{shared_lib_ext}")
-                destination = os.path.join(os.getcwd(), "build")
+                destination = os.path.join(os.getcwd(), self.build_temp)
                 shutil.copy(source, destination)
 
 with open(os.path.join("pennylane_lightning", "core", "_version.py"), encoding="utf-8") as f: