Qiskit / qiskit / 26231196555

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Commit Message

Fix Statevector.evolve modifying input state in-place (Fixes 15750) (#15905)

* [quantum_info.states] Add tests (1 failing) for Statevector.evolve modifying original state

Statevector.evolve() is meant to return the evolved state, with the
original state remaining unmodified. However, some instructions result
in the state being modified. The added tests validate
Statevector.evolve() with various gates, Operator, and QuantumCircuit.
The only instance where the original state is modified is with
DiagonalGate.

* [quantum_info.states] Use new _data array when applying global phase

The _data array of Statevector may be a shallow copy of another
Statevector. Applying a global phase in-place would modify the other
instances. A deep copy doesn't work as this breaks another test:

- test.python.primitives.test_statevector_estimator.TestStatevectorEstimator.test_reset

* [reno] Add bugfix releasenote

* Update releasenotes/notes/fix-statevector-evolve-inplace-modification-be2f31976d5a2e1d.yaml

Co-authored-by: Julien Gacon <gaconju@gmail.com>

* Update releasenotes/notes/fix-statevector-evolve-inplace-modification-be2f31976d5a2e1d.yaml

Co-authored-by: Julien Gacon <gaconju@gmail.com>

* [tests] Fix test names not being snake-case

* [tests] Fix lint black failing

---------

Co-authored-by: Julien Gacon <gaconju@gmail.com>

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5 existing lines in 3 files now uncovered.

108198 of 123676 relevant lines covered (87.49%)

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