Update the deprecation decorator towards SemVer

[1ucian0]

The current deprecate decorators extend the docstring with the following:

I suggest the following to be aligned with Qiskit/documentation#366

Other consequences:

• As part of this change, since= parameter should be a string. Sometimes, we accidentally use floats for it which is not correct in the generic case. So, it is good to raise in those cases.

[qiskit-bot]

One or more of the the following people are requested to review this:

• @Qiskit/terra-core

[mtreinish]

This works fine, but we should have sufficient info to compute the next major version from the since field. We could set this to None and then do something like:

if removal_timeline is None:
    removal_major = int(since.split(",")[0]) + 1
    removal_timeline = f"in the next major release {removal_major}"

Or if you're worried about deprecated features passing a major version boundary (e.g. we deprecate something in 1.0 and don't remove it until 3.0) we can replace since with the package's __version__.

[1ucian0]

good one! Done in cd47576

However, replacing since with __version__ might be tricky. If a features was deprecated in 1.1.0, we want to keep that since after the release of 1.2.0. Or am I missing something?

[coveralls]

Pull Request Test Coverage Report for Build 13319018940

Details

• 3 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• 29 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.03%) to 88.21%

---

Files with Coverage Reduction	New Missed Lines	%
crates/qasm2/src/lex.rs	5	91.73%
crates/qasm2/src/parse.rs	24	95.76%

Totals
Change from base Build 13318724701:	-0.03%
Covered Lines:	78581
Relevant Lines:	89084

---

💛 - Coveralls

[mergify]

backport stable/0.46

🟠 Waiting for conditions to match

• merged [📌 backport requirement]

[mtreinish]

As weird as this is to ask for on a deprecation decorator, I think this needs a release note as this is a public documented function and we're adding a new option and changing the default behavior. It will need a feature release note and an upgrade note as existing users who don't set removal_timeline will get different messages after upgrading qiskit.

[mtreinish]

Given that rc1 is supposed to go out today, I'm going to defer this to 1.1. We'll have to rework this PR to not be a breaking api change for 1.1, but I think that's manageable.

[1ucian0]

@Mergifyio dequeue

[mergify]

dequeue

☑️ The pull request is not queued

[1ucian0]

I think this needs a release note as this is a public documented function and we're [...] changing the default behavior.

Done in 97a2740