Transpiling fails if the target does not specify properties for measurement instructions

[hay-k]

Environment

• Qiskit Terra version: 0.22.0
• Python version: 3.9.12
• Operating system: Windows 10

What is happening?

Traceback (most recent call last):
  File ".\src\playground.py", line 86, in <module>
    qc_transpiled = transpile(qc, target=target)
  File ".\lib\site-packages\qiskit\compiler\transpiler.py", line 327, in transpile
    unique_transpile_args, shared_args = _parse_transpile_args(
  File ".\lib\site-packages\qiskit\compiler\transpiler.py", line 646, in _parse_transpile_args
    backend_properties = target_to_backend_properties(target)
  File ".\lib\site-packages\qiskit\transpiler\target.py", line 1021, in target_to_backend_properties
    if props.error is not None:
AttributeError: 'NoneType' object has no attribute 'error'

How can we reproduce the issue?

When building a transpiler target, the properties for added instructions are optional. The documentation of qiskit.transpiler.Target.add_instruction says Properties are optional for any instruction implementation, if there are no InstructionProperties available for the backend the value can be None.. However, it seems this claim is true for all instructions except measurement.

The below code snippet shows how to construct a very simple target with one qubit and measurement instruction associated with it. The measurement instruction does not have any properties (i.e. it is specified as None). Then, this target is used to transpile a circuit, which results into the error pasted above

from qiskit import QuantumCircuit
from qiskit.circuit.library import Measure
from qiskit.compiler import transpile
from qiskit.transpiler import Target

target = Target()
target.add_instruction(Measure(), {(0,): None})

qc = QuantumCircuit(1, 1)
qc.measure(0, 0)

transpile(qc, target=target)

What should happen?

The transpilation should not fail

Any suggestions?

No response