Add documentation warning: Don’t use torch.profiler.profile context manager around Trainer methods
What does this PR do?
This PR adds a prominent documentation warning to the Trainer class docstring (and optionally Profiler docs) to alert users not to wrap Trainer.fit(), Trainer.validate(), or similar methods inside a manual torch.profiler.profile context manager. Instead, users are advised to use the profiler argument in the Trainer constructor, which is the robust and officially supported method for profiling with Lightning.
This change aims to prevent a common source of cryptic internal errors and crashes reported by users who attempt to manually profile the Trainer, and improves developer experience by making the correct usage obvious in the docs.
Fixes #20779 (You can fill in the relevant issue if one exists, such as #16958)
This PR does not introduce any breaking changes.
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Was this discussed/agreed via a GitHub issue?
Yes, this has been discussed in Lightning issues and user forums (see: #16958 and PyTorch #88472).
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PyTorch Issue #88472
Lightning Issue #16958
StackOverflow community discussion
Thanks for considering this! This documentation improvement should help prevent many user headaches and support requests.
📚 Documentation preview 📚: https://pytorch-lightning--20864.org.readthedocs.build/en/20864/