Remove deprecated `BackendV1` elements, including base class, `providers.models` and `qobj` modules by ElePT · Pull Request #13793 · Qiskit/qiskit

ElePT · 2025-02-05T18:31:38Z

Summary

This PR builds upon (~~and is BLOCKED BY~~) the changes in #13805.
This PR removes BackendV1 and all related modules and utils. This includes:

from qiskit/providers:
- BackendV1
- BackendV2Converter
- convert_to_target
- BackendPropertyError
- BackendConfigurationError
from qiskit/providers/models: these were BackendV1 data structures. Full module removed
- BackendConfiguration
- BackendProperties
- BackendStatus
- QasmBackendConfiguration
- PulseBackendConfiguration
- UchannelLO
- GateConfig
- PulseDefaults
- Command
- JobStatus
- GateProperties
- Nduv
Removed PulseQobjDef from qiskit/providers/models (this steps a bit into pulse removal realm)
from qiskit/qobj: Full module removed.
- QobjExperimentHeader
- QobjHeader
- QasmQobj
- QasmQobjInstruction
- QasmQobjExperimentConfig
- QasmQobjExperiment
- QasmQobjConfig
- QasmExperimentCalibrations
- GateCalibration
- PulseQobj
- PulseQobjInstruction
- PulseQobjExperimentConfig
- PulseQobjExperiment
- PulseQobjConfig
- QobjMeasurementOption
- PulseLibraryItem

Note that there were two classes defined in the qobj utils (MeasLevel and MeasReturnType) used in the result class, so they have been moved to result/models.py.

TODOs

Reno

Details

What should we do with the "Migrate from BackendV1 to BackendV2" guide? Check with docs team to make sure it's covered somewhere else. -> Update: opened Add Migration guide from BackendV1 to BackendV2 documentation#2705
This removal breaks Aer, currently seen in image tests:

qiskit.exceptions.OptionalDependencyImportWarning: While trying to import 'Qiskit Aer', some components were located but raised other errors during import. You might have an incompatible version installed. Qiskit will continue as if the optional is not available.
module 'qiskit_aer' failed to import with: ImportError("cannot import name 'convert_to_target' from 'qiskit.providers' (/home/vsts/work/1/s/qiskit/providers/__init__.py)")

coveralls · 2025-02-17T15:49:27Z

Pull Request Test Coverage Report for Build 13684630517

Details

29 of 67 (43.28%) changed or added relevant lines in 9 files are covered.
12 unchanged lines in 6 files lost coverage.
Overall coverage increased (+1.1%) to 88.101%

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
qiskit/visualization/pulse_v2/device_info.py	0	1	0.0%
qiskit/visualization/gate_map.py	0	37	0.0%

Files with Coverage Reduction	New Missed Lines	%
qiskit/pulse/calibration_entries.py	1	83.49%
qiskit/pulse/parameter_manager.py	1	96.97%
qiskit/pulse/schedule.py	1	88.03%
qiskit/utils/deprecate_pulse.py	1	94.12%
crates/circuit/src/circuit_instruction.rs	3	89.46%
crates/qasm2/src/lex.rs	5	91.73%

Totals
Change from base Build 13683975981:	1.1%
Covered Lines:	75167
Relevant Lines:	85319

💛 - Coveralls

qiskit-bot · 2025-02-17T16:14:16Z

One or more of the following people are relevant to this code:

@Eric-Arellano
@abbycross
@beckykd
@enavarro51
@Qiskit/terra-core
@ajavadia
@levbishop
@nkanazawa1989
@t-imamichi

…moval

…55) BackendV1 and qiskit.qobj removals in Qiskit/qiskit#13793 cause the test in qiskit_neko/tests/experiments/test_tomography.py to fail. This is part of the tests that are blocking the Qiskit/qiskit#13793 and Qiskit/qiskit#13872 PR in Qiskit from being merged. There is a PR in Qiskit Experiments that address these removals: qiskit-community/qiskit-experiments#1526. Until it is merged, we need to skip this failing test. Tracked in #54

…moval

mtreinish

Overall this LGTM. Thanks for doing this! This finally finishes a process I started back in 2019 with #3383 of trying to clean up these interfaces. I'm glad to see that 4 years later we're finally able to remove this legacy code from Qiskit. This is incredibly satisfying to see.

I just had a couple small comments inline. I thinkt he only one that needs an update is the release notes one though.

mtreinish · 2025-03-05T18:07:12Z

 provider is anything that provides an external service to Qiskit. The typical
 example of this is a Backend provider which provides
 :class:`~qiskit.providers.Backend` objects which can be used for executing
-:class:`~qiskit.circuit.QuantumCircuit` and/or :class:`~qiskit.pulse.Schedule`


This PR doesn't remove schedules yet but it's fine. :)

mtreinish · 2025-03-05T18:16:05Z

-    If migrating a provider from :class:`~qiskit.providers.BackendV1`
-    one thing to keep in mind is for
-    backwards compatibility you might need to add a configuration method that
-    will build a :class:`~qiskit.providers.models.BackendConfiguration` object
-    and :class:`~qiskit.providers.models.BackendProperties` from the attributes
-    defined in this class for backwards compatibility.


We could have left this comment in the docstring because someone could conceivably be migrating from BackendV1 post removal (as part of fixing 2.0 compatibility). But it also is fine to remove it since this lives in the 1.4 docs.

mtreinish · 2025-03-05T18:45:48Z


 class Bloch:
    """Class for plotting data on the Bloch sphere.  Valid data can be
-    either points, vectors, or qobj objects.


lol, what!? There is nothing that ever took a qobj here afaik.

mtreinish · 2025-03-05T18:49:16Z

+    The ``BackendV1`` model has been removed following its deprecation in 
+    Qiskit 1.2.0. This includes the ``BackendV1`` class as well as related
+    modules and utils, as they have been superseded by the :class:`.BackendV2` 
+    model. The list of removed items includes:


You might want to mention this also includes things that previously could accept a backend v1 object like generate_preset_pass_manager etc.

mtreinish · 2025-03-05T18:51:06Z

+      legacy ``BackendV1`` components (such as ``BackendConfiguration`` or ``BackendProperties``)
+
+    * ``BackendPropertyError`` and ``BackendConfigurationError``: exceptions linked to removed classes
+


I think there are a couple of removals missing here. The ones I caught are:

Target.from_configuration() backend_properties` arg

target_to_backend_properties

I might have missed others though.

mtreinish

LGTM, thanks for the quick update.

This is an undocumented internal module, so not subject to the deprecation policy. The module has been empty since Qiskitgh-13793 (and the handful of other `qiskit.providers` PRs that logically went with that one) in the Qiskit 2.0 transition, but since everything was using precise imports, we didn't notice the `__init__` file was now useless.

This is an undocumented internal module, so not subject to the deprecation policy. The module has been empty since gh-13793 (and the handful of other `qiskit.providers` PRs that logically went with that one) in the Qiskit 2.0 transition, but since everything was using precise imports, we didn't notice the `__init__` file was now useless.

…15091) This is an undocumented internal module, so not subject to the deprecation policy. The module has been empty since Qiskitgh-13793 (and the handful of other `qiskit.providers` PRs that logically went with that one) in the Qiskit 2.0 transition, but since everything was using precise imports, we didn't notice the `__init__` file was now useless.

ElePT force-pushed the macro-removal branch from 7d6eb5e to ab1fa67 Compare February 5, 2025 19:01

This was referenced Feb 6, 2025

Remove pulse-related passes #13798

Merged

Remove fake backends based on BackendV1 and related tools #13805

Merged

ElePT force-pushed the macro-removal branch from ab1fa67 to 7c208de Compare February 17, 2025 15:24

ElePT changed the title ~~[WIP] Remove deprecated qobj, pulse module, and related tools from BackendV1~~ [WIP] Remove deprecated BackendV1 elements, including base class, providers.models and qobj modules Feb 17, 2025

ElePT added the on hold Can not fix yet label Feb 17, 2025

ElePT force-pushed the macro-removal branch from 7c208de to 935892b Compare February 17, 2025 16:11

ElePT changed the title ~~[WIP] Remove deprecated BackendV1 elements, including base class, providers.models and qobj modules~~ Remove deprecated BackendV1 elements, including base class, providers.models and qobj modules Feb 17, 2025

ElePT marked this pull request as ready for review February 17, 2025 16:14

ElePT requested review from a team, eggerdj, jyu00, nkanazawa1989, nonhermitian and wshanks as code owners February 17, 2025 16:14

ElePT added this to the 2.0.0 milestone Feb 17, 2025

eliarbel mentioned this pull request Feb 18, 2025

Remove pulse module files, pulse visualization and final cleanup #13872

Merged

1ucian0 assigned eliarbel and ElePT Feb 20, 2025

This was linked to issues Feb 24, 2025

Remove BackendV1 and related dependencies, deprecated in 1.2 #13708

Closed

Remove qobj, deprecated in 1.2 #13701

Closed

Remove BackendV1, converters, models, qobj and update tests.

b9c862f

ElePT force-pushed the macro-removal branch from 935892b to b9c862f Compare February 28, 2025 15:19

ElePT added 2 commits March 3, 2025 09:19

Merge branch 'main' of https://github.com/Qiskit/qiskit into macro-re…

488a1b2

…moval

Add reno

e7c984f

ElePT force-pushed the macro-removal branch from 033ae63 to e7c984f Compare March 3, 2025 09:59

ElePT removed the on hold Can not fix yet label Mar 3, 2025

Document migration of MeasLevel and MeasReturnType

27c2c63

ElePT force-pushed the macro-removal branch from d11f3a5 to 27c2c63 Compare March 4, 2025 16:34

Mix malformed table

9717823

mtreinish added priority: high Changelog: Removed Add a "Removed" entry in the GitHub Release changelog. labels Mar 4, 2025

ElePT mentioned this pull request Mar 5, 2025

Update use of classes removed in Qiskit 2.0 Qiskit/qiskit-ibm-runtime#2173

Merged

wshanks mentioned this pull request Mar 5, 2025

Prepare for Qiskit 2.0 by addressing removed classes and methods qiskit-community/qiskit-experiments#1526

Merged

eliarbel mentioned this pull request Mar 5, 2025

Skip StateTomography test until Qiskit Experiments is ready for 2.0 Qiskit/qiskit-neko#55

Merged

ElePT mentioned this pull request Mar 5, 2025

Skip qiskit-machine-learning tests until the downstream dependencies are updated to 2.0 Qiskit/qiskit-neko#56

Merged

Merge branch 'main' of https://github.com/Qiskit/qiskit into macro-re…

2467e16

…moval

mtreinish reviewed Mar 5, 2025

View reviewed changes

ElePT and others added 2 commits March 5, 2025 20:41

Apply comments from Matt's review

79a7b66

Merge branch 'main' into macro-removal

79c92be

mtreinish approved these changes Mar 5, 2025

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mtreinish enabled auto-merge March 5, 2025 20:11

mtreinish added this pull request to the merge queue Mar 5, 2025

github-merge-queue Bot removed this pull request from the merge queue due to failed status checks Mar 5, 2025

ElePT added this pull request to the merge queue Mar 5, 2025

github-merge-queue Bot removed this pull request from the merge queue due to failed status checks Mar 5, 2025

mtreinish added this pull request to the merge queue Mar 5, 2025

Merged via the queue into Qiskit:main with commit 9c00a93 Mar 5, 2025

valente mentioned this pull request Mar 28, 2025

Fix result.to_dict() following new 2.0 typing #14124

Merged

mergify Bot mentioned this pull request Mar 31, 2025

Fix result.to_dict() following new 2.0 typing (backport #14124) #14137

Merged

raynelfss mentioned this pull request Apr 1, 2025

Fix: Incorrect initialization of BackendV2 for transpiler_level ASV Test #14152

Merged

jakelishman mentioned this pull request Sep 29, 2025

Remove empty internal qiskit.providers.fake_provider.utils #15091

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Remove deprecated `BackendV1` elements, including base class, `providers.models` and `qobj` modules#13793

Remove deprecated `BackendV1` elements, including base class, `providers.models` and `qobj` modules#13793
mtreinish merged 15 commits intoQiskit:mainfrom
ElePT:macro-removal

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		legacy ``BackendV1`` components (such as ``BackendConfiguration`` or ``BackendProperties``)

		* ``BackendPropertyError`` and ``BackendConfigurationError``: exceptions linked to removed classes

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