Deprecate legacy qasm2 parser for 0.46 #11347
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The legacy qasm2 parser was remvoed on the main branch already in Qiskit#11308 for the 1.0.0 release. To ensure that users of the 0.x release series are warned of this API change this commit marks the functionality removed in Qiskit#11308 as deprecated for the 0.46.0 release.
mtreinish
added
Changelog: Deprecation
| legacy parser is removed. If you were previously using this, you can | ||
| instead parse your OpenQASM 2 files into a :class:`.QuantumCircuit` using | ||
| the :meth:`.QuantumCircuit.from_qasm_file` or | ||
| :meth:`.QuantumCircuit.from_qasm_str` constructor methods and then |
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I may have forgotten about this in the other PR, but weren't we planning to get rid of these and require use of qasm2.loads as well?
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We kept them in the other PR. At least for me the circuit constructor class methods still have value just in that I don't need to remember all the extra arguments to the parser to get it to behave like the legacy parser did (which is the only mode I ever really use for parsing qasm2).
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That's fair. I think we ought to remove those methods once we've implemented #10737 and made qasm2.dumps match it, at which point qasm2.loads will load the output of qasm2.dumps without any additional modifications. The arguments in favour of removing QuantumCircuit.qasm also imo hold for from_qasm_str, it's just the usability concern that you're correctly pointing out in the way, I think.
Summary
The legacy qasm2 parser was remvoed on the main branch already in #11308 for the 1.0.0 release. To ensure that users of the 0.x release series are warned of this API change this commit marks the functionality removed in #11308 as deprecated for the 0.46.0 release.
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