Refresh the internal LightningOptimizer state for inspection

[awaelchli]

What does this PR do?

Fixes #18279

Our internal wrapper LightningOptimizer can't guarantee to keep 100% in sync with internal variables of the optimizer it wraps. This is not an issue for optimization, because the wrapper is only used to redirect the step() call, and optimization always uses the real optimizer. This PR ensures the internal state is updated in case the user accesses the LightningOptimizer through self.optimizers() in the LightningModule and inspects its state.

cc @Borda

[github-actions]

⚡ Required checks status: All passing 🟢

Groups summary

🟢 pytorch_lightning: Tests workflow

Check ID	Status
pl-cpu (macOS-11, lightning, 3.8, 1.11)	success	✅
pl-cpu (macOS-11, lightning, 3.9, 1.12)	success	✅
pl-cpu (macOS-11, lightning, 3.10, 1.13)	success	✅
pl-cpu (macOS-11, lightning, 3.10, 2.0)	success	✅
pl-cpu (macOS-11, lightning, 3.8, 1.11, oldest)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.8, 1.11)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.9, 1.12)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.10, 1.13)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.10, 2.0)	success	✅
pl-cpu (ubuntu-20.04, lightning, 3.8, 1.11, oldest)	success	✅
pl-cpu (windows-2022, lightning, 3.8, 1.11)	success	✅
pl-cpu (windows-2022, lightning, 3.9, 1.12)	success	✅
pl-cpu (windows-2022, lightning, 3.10, 1.13)	success	✅
pl-cpu (windows-2022, lightning, 3.10, 2.0)	success	✅
pl-cpu (windows-2022, lightning, 3.8, 1.11, oldest)	success	✅
pl-cpu (macOS-11, pytorch, 3.8, 1.13)	success	✅
pl-cpu (ubuntu-20.04, pytorch, 3.8, 1.13)	success	✅
pl-cpu (windows-2022, pytorch, 3.8, 1.13)	success	✅

These checks are required after the changes to src/lightning/pytorch/core/module.py, src/lightning/pytorch/core/optimizer.py, tests/tests_pytorch/core/test_lightning_optimizer.py, tests/tests_pytorch/strategies/test_fsdp.py.

🟢 pytorch_lightning: Azure GPU

Check ID	Status
[pytorch-lightning (GPUs) (testing Lightning	latest)](https://dev.azure.com/Lightning-AI/72ab7ed8-b00f-4b6e-b131-3388f7ffafa7/_build/results?buildId=169495&view=logs&jobId=47e66f3c-897a-5428-da11-bf5c7745762e)	success
[pytorch-lightning (GPUs) (testing PyTorch	latest)](https://dev.azure.com/Lightning-AI/72ab7ed8-b00f-4b6e-b131-3388f7ffafa7/_build/results?buildId=169495&view=logs&jobId=3f274fac-2e11-54ca-487e-194c91f3ae9f)	success

These checks are required after the changes to src/lightning/pytorch/core/module.py, src/lightning/pytorch/core/optimizer.py, tests/tests_pytorch/core/test_lightning_optimizer.py, tests/tests_pytorch/strategies/test_fsdp.py.

🟢 pytorch_lightning: Benchmarks

Check ID	Status
lightning.Benchmarks	success	✅

These checks are required after the changes to src/lightning/pytorch/core/module.py, src/lightning/pytorch/core/optimizer.py.

🟢 pytorch_lightning: Docs

Check ID	Status
make-doctest (pytorch)	success	✅
make-html (pytorch)	success	✅

These checks are required after the changes to src/lightning/pytorch/core/module.py, src/lightning/pytorch/core/optimizer.py.

🟢 mypy

Check ID	Status
mypy	success	✅

These checks are required after the changes to src/lightning/pytorch/core/module.py, src/lightning/pytorch/core/optimizer.py.

🟢 install

Check ID	Status
install-pkg (ubuntu-22.04, app, 3.8)	success	✅
install-pkg (ubuntu-22.04, app, 3.10)	success	✅
install-pkg (ubuntu-22.04, fabric, 3.8)	success	✅
install-pkg (ubuntu-22.04, fabric, 3.10)	success	✅
install-pkg (ubuntu-22.04, pytorch, 3.8)	success	✅
install-pkg (ubuntu-22.04, pytorch, 3.10)	success	✅
install-pkg (ubuntu-22.04, lightning, 3.8)	success	✅
install-pkg (ubuntu-22.04, lightning, 3.10)	success	✅
install-pkg (ubuntu-22.04, notset, 3.8)	success	✅
install-pkg (ubuntu-22.04, notset, 3.10)	success	✅
install-pkg (macOS-12, app, 3.8)	success	✅
install-pkg (macOS-12, app, 3.10)	success	✅
install-pkg (macOS-12, fabric, 3.8)	success	✅
install-pkg (macOS-12, fabric, 3.10)	success	✅
install-pkg (macOS-12, pytorch, 3.8)	success	✅
install-pkg (macOS-12, pytorch, 3.10)	success	✅
install-pkg (macOS-12, lightning, 3.8)	success	✅
install-pkg (macOS-12, lightning, 3.10)	success	✅
install-pkg (macOS-12, notset, 3.8)	success	✅
install-pkg (macOS-12, notset, 3.10)	success	✅
install-pkg (windows-2022, app, 3.8)	success	✅
install-pkg (windows-2022, app, 3.10)	success	✅
install-pkg (windows-2022, fabric, 3.8)	success	✅
install-pkg (windows-2022, fabric, 3.10)	success	✅
install-pkg (windows-2022, pytorch, 3.8)	success	✅
install-pkg (windows-2022, pytorch, 3.10)	success	✅
install-pkg (windows-2022, lightning, 3.8)	success	✅
install-pkg (windows-2022, lightning, 3.10)	success	✅
install-pkg (windows-2022, notset, 3.8)	success	✅
install-pkg (windows-2022, notset, 3.10)	success	✅

These checks are required after the changes to src/lightning/pytorch/core/module.py, src/lightning/pytorch/core/optimizer.py.

🟢 link-check

Check ID	Status
check-md-links / markdown-link-check	success	✅

These checks are required after the changes to src/lightning/pytorch/CHANGELOG.md.

---

Thank you for your contribution! 💜

Note
This comment is automatically generated and updates for 60 minutes every 180 seconds. If you have any other questions, contact carmocca for help.