From 50fa4e31303f21ac2123cb4077cf9deaedcc611f Mon Sep 17 00:00:00 2001
From: Kartik Singhal <kartik.singhal@quantinuum.com>
Date: Wed, 27 Mar 2024 13:48:00 -0600
Subject: [PATCH] fix(phirgen): don't rely on `args` when `qubits` carries
 correct info (#155)

---
 pytket/phir/phirgen.py |  2 +-
 tests/test_phirgen.py  | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/pytket/phir/phirgen.py b/pytket/phir/phirgen.py
index 0ab6cd4..de76eaa 100644
--- a/pytket/phir/phirgen.py
+++ b/pytket/phir/phirgen.py
@@ -187,7 +187,7 @@ def convert_gate(op: tk.Op, cmd: tk.Command) -> JsonDict | None:
             qop = {
                 "qop": gate,
                 "returns": [arg_to_bit(cmd.bits[0])],
-                "args": [arg_to_bit(cmd.args[0])],
+                "args": [arg_to_bit(cmd.qubits[0])],
             }
         case ("CX"
             | "CY"
diff --git a/tests/test_phirgen.py b/tests/test_phirgen.py
index 758f82a..6002a07 100644
--- a/tests/test_phirgen.py
+++ b/tests/test_phirgen.py
@@ -174,3 +174,17 @@ def test_reordering_classical_conditional() -> None:
         "condition": {"args": [["ctrl", 0], 1], "cop": "=="},
         "true_branch": [{"angles": None, "args": [["q", 0]], "qop": "X"}],
     }
+
+
+def test_conditional_measure() -> None:
+    """From https://github.com/CQCL/pytket-phir/issues/154 ."""
+    c = Circuit(2, 2)
+    c.H(0).H(1)
+    c.Measure(0, 0)
+    c.Measure(1, 1, condition_bits=[0], condition_value=1)
+    phir = json.loads(pytket_to_phir(c))
+    assert phir["ops"][-1] == {
+        "block": "if",
+        "condition": {"cop": "==", "args": [["c", 0], 1]},
+        "true_branch": [{"qop": "Measure", "returns": [["c", 1]], "args": [["q", 1]]}],
+    }