Add more c-api error functions by bschoenmaeckers · Pull Request #7915 · RustPython/RustPython

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Run ID: 32073fb1-a88b-49f0-b4fe-29d63ab33259

📥 Commits

Reviewing files that changed from the base of the PR and between 737ad27 and 7bda56a.

📒 Files selected for processing (3)

crates/capi/src/lib.rs
crates/capi/src/pyerrors.rs
crates/capi/src/traceback.rs

✅ Files skipped from review due to trivial changes (1)

crates/capi/src/lib.rs

🚧 Files skipped from review as they are similar to previous changes (2)

crates/capi/src/pyerrors.rs
crates/capi/src/traceback.rs

📝 Walkthrough

Walkthrough

This PR adds C-API predicates and getters for exception inspection, an FFI binding PyTraceBack_Print that calls Python's traceback.print_tb inside the VM, and re-exports the traceback module from the crates/capi crate root.

Changes

Exception and Traceback C-API Bindings

Layer / File(s)	Summary
Exception inspection C-API `crates/capi/src/pyerrors.rs`	Imports `define_py_check`, exports `PyExceptionInstance_Check`, adds `PyExceptionClass_Check` to test exception classes for subtype relationship, and implements `PyException_GetTraceback`, `PyException_GetCause`, and `PyException_GetContext` returning raw `PyObject*` or null.
Traceback printing binding `crates/capi/src/traceback.rs`	Defines `PyTraceBack_Check` predicate and implements `pub unsafe extern "C" fn PyTraceBack_Print(tb, file) -> c_int` which enters the VM, imports `traceback`, and calls `print_tb(tb, file=...)`.
Traceback module export `crates/capi/src/lib.rs`	Adds `pub mod traceback;` to expose the traceback binding module from the crate root.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

RustPython/RustPython#7787: Related changes to exception-typing support used by the new PyException* C-API functions.
RustPython/RustPython#7871: Introduced the define_py_check! macro machinery used to generate exported type/subtype predicates.

Suggested reviewers

youknowone

Poem

🐰 With paws on keys and whiskers bright,
I call print_tb into the night.
Exceptions scanned and tracebacks shown,
The C-API sings in careful tone.
Hoppity hop — the bindings grown.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title describes the addition of C-API error functions, which is partially reflected in the changeset. However, the changes also include traceback functionality (new traceback module export and PyTraceBack_Print), which goes beyond just error functions and is not mentioned in the title.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

Create PR with unit tests

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