Miscellaneous fixes to the unified compiler (#2274)

* Update MLIR graph tests so that they are skipped if at least one of
the following conditions is not met:
  * The Python `graphviz` package is not installed
  * The system-level `graphviz` package is not installed
* Update a test for the xDSL Quantum dialect that was causing the
`--force-flaky` workflow to fail
* Update version of PennyLane in `.dep-versions`
* Move changelog entry for `qml.specs` integration with xDSL to the
correct section

Author: mudit2812

.dep-versions

@@ -10,7 +10,7 @@ enzyme=v0.0.203
 
 # For a custom PL version, update the package version here and at
 # 'doc/requirements.txt'
-pennylane=0.44.0-dev44
+pennylane=0.44.0-dev48
 
 # For a custom LQ/LK version, update the package version here and at
 # 'doc/requirements.txt'

doc/releases/changelog-dev.md

@@ -10,6 +10,11 @@
   `catalyst.python_interface` namespace.
   [(#2199)](https://github.com/PennyLaneAI/catalyst/pull/2199)
 
+  * A new `catalyst.python_interface.inspection.mlir_specs` function has been added to facilitate
+    PennyLane's new pass-by-pass specs feature. This function returns information gathered by parsing
+    the xDSL generated by a given QJIT object, such as gate counts, measurements, or qubit allocations.
+    [(#2238)](https://github.com/PennyLaneAI/catalyst/pull/2238)
+
   This functionality was originally developed as part of the PennyLane package, and has been migrated here.
   For earlier development notes to the feature, please refer to the
   [PennyLane release notes](https://docs.pennylane.ai/en/stable/development/release_notes.html#release-0-43-0).
@@ -361,11 +366,6 @@
 
 <h3>Internal changes ⚙️</h3>
 
-* A new `catalyst.python_interface.inspection.mlir_specs` method has been added to facilitate
-  PennyLane's new pass-by-pass specs feature. This function returns information gathered by parsing
-  the xDSL generated by a given QJIT object, such as gate counts, measurements, or qubit allocations.
-  [(#2238)](https://github.com/PennyLaneAI/catalyst/pull/2238)
-
 * Resource tracking now writes out at device destruction time instead of qubit deallocation
   time. The written resources will be the total amount of resources collected throughout the
   lifetime of the execution. For executions that split work between multiple functions,

doc/requirements.txt

@@ -33,4 +33,4 @@ lxml_html_clean
 --extra-index-url https://test.pypi.org/simple/
 pennylane-lightning-kokkos==0.44.0-dev16
 pennylane-lightning==0.44.0-dev16
-pennylane==0.44.0-dev44
+pennylane==0.44.0-dev48

frontend/test/pytest/python_interface/dialects/test_quantum_dialect.py

@@ -13,7 +13,6 @@
 # limitations under the License.
 
 """Unit tests for the xDSL Quantum dialect."""
-
 import pytest
 
 # pylint: disable=wrong-import-position
@@ -30,7 +29,7 @@
     i1,
 )
 from xdsl.dialects.test import TestOp
-from xdsl.ir import AttributeCovT, OpResult
+from xdsl.ir import AttributeCovT, Block, Operation, OpResult, Region
 
 from catalyst.python_interface.dialects import Quantum
 from catalyst.python_interface.dialects.quantum import (
@@ -115,7 +114,10 @@ def create_ssa_value(t: AttributeCovT) -> OpResult[AttributeCovT]:
 state = create_ssa_value(TensorType(ComplexType(Float64Type()), shape=(16,)))
 
 expected_ops_init_kwargs = {
-    "AdjointOp": {"qreg": qreg, "region": (CustomOp(gate_name="CNOT", in_qubits=(q0, q1)),)},
+    "AdjointOp": {
+        "qreg": qreg,
+        "region": Region(Block((CustomOp(gate_name="CNOT", in_qubits=(q0, q1)),))),
+    },
     "AllocOp": {"nqubits": 3},
     "AllocQubitOp": {},
     "ComputationalBasisOp": {"operands": (q0, None), "result_types": (obs,)},
@@ -203,7 +205,10 @@ def test_only_existing_operations_are_expected():
 @pytest.mark.parametrize("op", all_ops)
 def test_operation_construction(op):
     """Test the constructors of operations in the Quantum dialect."""
-    kwargs = expected_ops_init_kwargs[op.__name__]
+    kwargs = {
+        k: v.clone() if isinstance(v, (Operation, Region)) else v
+        for k, v in expected_ops_init_kwargs[op.__name__].items()
+    }
     _ = op(**kwargs)
 
 

frontend/test/pytest/python_interface/inspection/test_mlir_graph.py

@@ -14,6 +14,7 @@
 """Unit test module for the MLIR graph generation in the Unified Compiler visualization module."""
 
 from pathlib import Path
+from subprocess import run
 
 import pytest
 
@@ -22,6 +23,10 @@
 xdsl = pytest.importorskip("xdsl")
 graphviz = pytest.importorskip("graphviz")
 
+if run(["/usr/bin/which", "dot"], check=False).returncode != 0:
+    pytest.skip(reason="Graphviz isn't installed.")
+
+
 import pennylane as qml
 
 from catalyst.passes.xdsl_plugin import getXDSLPluginAbsolutePath