[typing] fix some pyrefly unbound local errors

[jakevdp]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @jakevdp, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses several issues related to potential unbound local variables and non-exhaustive pattern matching, likely identified by a static analysis tool. The changes primarily involve ensuring variables are always initialized before use, refactoring conditional assignments for clarity and safety, and adding exhaustive case statements in match blocks to improve code robustness and satisfy stricter type checking requirements.

Highlights

• Unbound Local Variable Fixes: Initialized const_args in jax/_src/api.py and sharded_shape in jax/_src/sharding_impls.py to prevent potential unbound local variable errors.
• Debugger Logic Refinement: Refactored source code retrieval logic in jax/_src/debugger/colab_debugger.py to ensure source, highlight, and linenostart are consistently defined.
• Exhaustive Pattern Matching: Enhanced exhaustiveness checks in jax/_src/lax/lax.py, jax/_src/pallas/mosaic/sc_primitives.py, and jax/_src/pallas/triton/lowering.py by adding default case _: statements to handle unexpected enum values or types, improving robustness and static analysis compliance.
• Error Handling Improvement: Added a fallback RuntimeError in jax/_src/pjit.py to guarantee an exception is raised after a NaN check, ensuring expected error propagation.
• Code Cleanup: Removed an unused _cached_scan_pad_jaxpr function from jax/_src/lax/control_flow/loops.py.

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Changelog

• jax/_src/api.py
  • Initialized const_args list to prevent unbound local variable errors.
• jax/_src/debugger/colab_debugger.py
  • Refactored the logic for assigning source, highlight, and linenostart to ensure they are always defined, regardless of FileNotFoundError.
• jax/_src/lax/control_flow/loops.py
  • Removed the _cached_scan_pad_jaxpr function and its associated weakref_lru_cache decorator.
• jax/_src/lax/lax.py
  • Added a default case _: to the RaggedDotMode pattern matching in grad_x_dims and grad_y_dims to handle all possible modes explicitly.
• jax/_src/pallas/mosaic/sc_primitives.py
  • Added a default case _: to the PackFormat pattern matching in _pack_abstract_eval to raise an error for unexpected formats.
• jax/_src/pallas/triton/lowering.py
  • Added a default case _: to the pattern matching in _compute_offsets_from_indices to raise an error for unexpected dim_block_size types.
• jax/_src/pjit.py
  • Introduced a fallback RuntimeError after api_util.maybe_recursive_nan_check to ensure an exception is always raised in that code path.
• jax/_src/sharding_impls.py
  • Initialized sharded_shape with global_shape to prevent potential unbound local variable errors.

Activity

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[gemini-code-assist]

Code Review

This pull request provides a set of fixes for potential unbound local errors identified by static analysis. The changes are spread across several files and generally involve initializing variables before conditional blocks where they are assigned, or making match statements exhaustive to ensure all code paths are handled. These changes improve code robustness and correctness. I've reviewed all the changes and they look good.

[superbobry]

Nice find!

[superbobry]

f?