Fix deprecation warning of unscheduled circuits in timeline drawer (#…

…10851)

The warning was previously emitted with a `stacklevel` that blamed the
caller of `warnings.warn`, which would not be shown to users with the
default warning filters.  This moves the stack level up to blame the
caller of `timeline_drawer`.

qiskit/transpiler/passes/scheduling/dynamical_decoupling.py

@@ -53,6 +53,20 @@ class DynamicalDecoupling(TransformationPass):
         from qiskit.transpiler import PassManager, InstructionDurations
         from qiskit.transpiler.passes import ALAPSchedule, DynamicalDecoupling
         from qiskit.visualization import timeline_drawer
+
+        # Because the legacy passes do not propagate the scheduling information correctly, it is
+        # necessary to run a no-op "re-schedule" before the output circuits can be drawn.
+        def draw(circuit):
+            from qiskit import transpile
+
+            scheduled = transpile(
+                circuit,
+                optimization_level=0,
+                instruction_durations=InstructionDurations(),
+                scheduling_method="alap",
+            )
+            return timeline_drawer(scheduled)
+
         circ = QuantumCircuit(4)
         circ.h(0)
         circ.cx(0, 1)
@@ -69,7 +83,7 @@ class DynamicalDecoupling(TransformationPass):
         pm = PassManager([ALAPSchedule(durations),
                           DynamicalDecoupling(durations, dd_sequence)])
         circ_dd = pm.run(circ)
-        timeline_drawer(circ_dd)
+        draw(circ_dd)
 
         # Uhrig sequence on qubit 0
         n = 8
@@ -87,7 +101,7 @@ def uhrig_pulse_location(k):
             ]
         )
         circ_dd = pm.run(circ)
-        timeline_drawer(circ_dd)
+        draw(circ_dd)
     """
 
     @deprecate_func(

qiskit/visualization/timeline/core.py

@@ -159,6 +159,7 @@ def load_program(self, program: circuit.QuantumCircuit):
                 "This circuit should be transpiled with scheduler though it consists of "
                 "instructions with explicit durations.",
                 DeprecationWarning,
+                stacklevel=3,
             )
 
             try:

releasenotes/notes/fix-timeline-draw-unscheduled-warning-873f7a24c6b51e2c.yaml

@@ -0,0 +1,22 @@
+---
+deprecations:
+  - |
+    Passing a circuit to :func:`qiskit.visualization.timeline_drawer` that does not have scheduled
+    node start-time information is deprecated.  Only circuits that have gone through one of the
+    scheduling analysis passes (for example :class:`.ALAPScheduleAnalysis` or
+    :class:`.ASAPScheduleAnalysis`) can be visualised.  If you have used one of the old-style
+    scheduling passes (for example :class:`.ALAPSchedule` or :class:`.ASAPSchedule`), you can
+    propagate the scheduling information by running::
+
+      from qiskit import transpile
+      from qiskit.transpiler import InstructionDurations
+
+      scheduled = transpile(
+        my_old_style_circuit,
+        optimization_level=0,
+        scheduling_method="alap",
+        instruction_durations=InstructionDurations(),
+      )
+
+    This behaviour was previously intended to be deprecated in Qiskit 0.37, but due to a bug in the
+    warning, it was not displayed to users until now.  The behaviour will be removed in Qiskit 1.0.