Fix Pulse channel index validation (#10476)

* Correct channel index validation

* Add tests and release note.

qiskit/pulse/channels.py

@@ -121,7 +121,7 @@ def _validate_index(self, index: Any) -> None:
             if index.is_integer():
                 index = int(index)
 
-        if not isinstance(index, (int, np.integer)) and index < 0:
+        if not isinstance(index, (int, np.integer)) or index < 0:
             raise PulseError("Channel index must be a nonnegative integer")
 
     @property

releasenotes/notes/channel-validation-bug-fix-c06f8445cecc8478.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Fixed a bug in :class:`.pulse.Channel` where index validation was done incorrectly and only
+    raised an error when the index was both non-integer and negative, instead of either.

test/python/pulse/test_channels.py

@@ -25,6 +25,7 @@
     PulseChannel,
     RegisterSlot,
     SnapshotChannel,
+    PulseError,
 )
 from qiskit.test import QiskitTestCase
 
@@ -88,6 +89,13 @@ def test_default(self):
         self.assertEqual(memory_slot.name, "m123")
         self.assertTrue(isinstance(memory_slot, ClassicalIOChannel))
 
+    def test_validation(self):
+        """Test channel validation"""
+        with self.assertRaises(PulseError):
+            MemorySlot(0.5)
+        with self.assertRaises(PulseError):
+            MemorySlot(-1)
+
 
 class TestRegisterSlot(QiskitTestCase):
     """RegisterSlot tests."""
@@ -100,6 +108,13 @@ def test_default(self):
         self.assertEqual(register_slot.name, "c123")
         self.assertTrue(isinstance(register_slot, ClassicalIOChannel))
 
+    def test_validation(self):
+        """Test channel validation"""
+        with self.assertRaises(PulseError):
+            RegisterSlot(0.5)
+        with self.assertRaises(PulseError):
+            RegisterSlot(-1)
+
 
 class TestSnapshotChannel(QiskitTestCase):
     """SnapshotChannel tests."""
@@ -123,6 +138,13 @@ def test_default(self):
         self.assertEqual(drive_channel.index, 123)
         self.assertEqual(drive_channel.name, "d123")
 
+    def test_validation(self):
+        """Test channel validation"""
+        with self.assertRaises(PulseError):
+            DriveChannel(0.5)
+        with self.assertRaises(PulseError):
+            DriveChannel(-1)
+
 
 class TestControlChannel(QiskitTestCase):
     """ControlChannel tests."""
@@ -134,6 +156,13 @@ def test_default(self):
         self.assertEqual(control_channel.index, 123)
         self.assertEqual(control_channel.name, "u123")
 
+    def test_validation(self):
+        """Test channel validation"""
+        with self.assertRaises(PulseError):
+            ControlChannel(0.5)
+        with self.assertRaises(PulseError):
+            ControlChannel(-1)
+
 
 class TestMeasureChannel(QiskitTestCase):
     """MeasureChannel tests."""
@@ -145,6 +174,13 @@ def test_default(self):
         self.assertEqual(measure_channel.index, 123)
         self.assertEqual(measure_channel.name, "m123")
 
+    def test_validation(self):
+        """Test channel validation"""
+        with self.assertRaises(PulseError):
+            MeasureChannel(0.5)
+        with self.assertRaises(PulseError):
+            MeasureChannel(-1)
+
 
 if __name__ == "__main__":
     unittest.main()