Preserve partial keyword identity through vectorcall by youknowdot · Pull Request #9127 · RustPython/RustPython

youknowdot · 2026-10-14T18:16:54Z

Summary

Extract the Python 3.15 final functools.partial vectorcall changes from #8954, including the required CALL_FUNCTION_EX dependency.

Preserve keyword string-subclass objects through ordinary and instrumented CALL_FUNCTION_EX calls.
Merge partial keywords without eagerly normalizing their identities, and snapshot the wrapped function, arguments and keywords before Python hash/equality callbacks can replace partial state.
Preserve placeholder handling and the existing fallback for wrapped callables without vectorcall.

No Lib/ files or existing tests are modified.

Validation

Fresh narrow release build with threading, stdlib, stdio, importlib and host_env: passed.
Nineteen unchanged canonical CPython v3.15.0 test cases, each run in a separate process with a 30-second / 1-GiB bound: passed, zero skips. These cover partial arguments/placeholders/subclasses/keyword errors, kwargs ordering, instrumented CALL_FUNCTION_EX, and one reentrant state replacement with one gc.collect() call.
Strict VM/stdlib all-target Clippy with compiler/threading/host_env and -D warnings: passed.
Configured hooks and git diff --check: passed.

The first two-file extraction failed the unchanged test_str_subclass_error: the existing CALL_FUNCTION_EX path discarded the keyword subclass before partial saw it. The frame change fixes that missing prerequisite; the same assertion now passes.

Canonical tests were source-preserved in external bounded runners from CPython final d220409a13b77de7a6c30abe16ea90db01528edc. Full workspace/C-API suites, broad monitoring coverage, stress/concurrency probes and other platforms were not run locally; hosted CI remains required. The one reentrant test is not a general GC or concurrency safety claim.

AI-assisted implementation and validation with OpenAI Codex.

Review follow-up

Registered PyPartial::vectorcall directly with the existing #[pyslot] support instead of an extend_class hook.
Replaced the incoming-keyword downcast panic in the non-vectorcall fallback with TypeError. This is defensive handling; malformed raw vectorcall keyword names violate CPython's C-API caller contract.
Fresh narrow release build passed; 10 unchanged final CPython methods passed for both native partial and a plain subclass (20 bounded invocations, zero skips). Separate bounded checks verified direct and state-installed nested subclass __call__ overrides. Strict VM/stdlib all-target Clippy (-D warnings) and normal commit hooks passed.

Summary by CodeRabbit

Bug Fixes
- Improved calls using unpacked positional and keyword arguments, including keyword names provided by string subclasses.
- Improved partial-function calls with placeholders and stored keyword arguments, while preserving compatibility with callables that use a different calling mechanism.
- Improved call-monitoring event details for calls made without positional arguments, so monitoring receives the appropriate missing-value indicator when no positional argument is present.

Retain keyword objects in CALL_FUNCTION_EX and snapshot partial state before Python callbacks. Match CPython 3.15 final partial keyword merging without changing Lib or tests. Assisted-by: OpenAI Codex:model version unavailable

coderabbitai · 2026-10-14T18:17:05Z

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crates/vm/src/stdlib/_functools.rs

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📝 Walkthrough

Extended calls now collect positional arguments and keyword names separately and dispatch through vectorcall. PyPartial adds vectorcall handling, including placeholder filling and keyword merging. The dict-key hashing helper is available to other modules in the crate.

Changes: Call Dispatch

Layer / File(s)	Summary
Extended-call argument collection and wiring `crates/vm/src/frame.rs`	`collect_ex_args` returns positional values and keyword names separately. It requires keyword keys to be strings and preserves the original key objects. Both extended-call opcodes use this representation.
Vectorcall execution and instrumentation `crates/vm/src/frame.rs`	`execute_call_ex` invokes vectorcall with keyword names. Instrumented calls report the first positional argument, or the missing-value sentinel, and handle call and C return or raise events.
PyPartial vectorcall and keyword merging `crates/vm/src/builtins/dict.rs`, `crates/vm/src/stdlib/_functools.rs`	`PyDict::hash_or_unhashable` becomes crate-visible. `PyPartial` fills placeholders and merges stored and incoming keywords. It uses vectorcall when supported and retains a `FuncArgs` fallback.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant CALL_FUNCTION_EX
  participant collect_ex_args
  participant execute_call_ex
  participant vectorcall
  participant monitoring
  CALL_FUNCTION_EX->>collect_ex_args: collect positional values and keyword names
  collect_ex_args-->>CALL_FUNCTION_EX: return arguments and names
  CALL_FUNCTION_EX->>execute_call_ex: dispatch collected arguments
  execute_call_ex->>vectorcall: invoke callable with keyword names
  execute_call_ex->>monitoring: report events when instrumented

Suggested reviewers: youknowone

Merge Risk: ⚪ Minimal · up to b6c25

The change preserves keyword string-subclass identity through extended calls and partial vectorcall, with the earlier non-string keyword panic fixed. No concrete merge-blocking risk is evidenced; hosted CI is still needed.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 75.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: preserving partial keyword identity through vectorcall.

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chatgpt-codex-connector · 2026-10-15T01:29:19Z

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Review	Status	Commit	Review trigger
📝 Code Review	⚠️ Failed 2026-10-15T02:06:14.978453Z	`b6c253d`	New commits

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youknowone · 2026-10-15T01:30:52Z

        flags(BASETYPE, HAS_DICT, HAS_WEAKREF)
    )]
    impl PyPartial {
+        #[extend_class]


rather than doing this, add another macro support to naturally bind fn ventorcall to slots.vectorcall.
probably #[pyslot] fn vectorcall will be enough

Updated in b6c253d. vectorcall now uses #[pyslot] in the existing #[pyclass] impl; the macro already supports this binding, so no additional macro implementation was needed.

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Actionable comments posted: 1

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Inline comments:
Review comments at @crates/vm/src/stdlib/_functools.rs:
- Around line 598-615: Update the kwnames loop in PyPartial::vectorcall to
return a TypeError when a keyword name is not a PyStr, matching the validation
used for stored keywords, instead of unwrapping and panicking.

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crates/vm/src/builtins/dict.rs
crates/vm/src/frame.rs
crates/vm/src/stdlib/_functools.rs

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Use the existing slot macro instead of a class extension hook. Return TypeError for non-string incoming names in the non-vectorcall fallback rather than panicking. Assisted-by: OpenAI Codex:model version unavailable

chatgpt-codex-connector · 2026-10-15T02:06:23Z

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Rebase the remaining integration onto current main while retaining merged compiler and runtime fixes. Import canonical CPython v3.15.0 library sources through update_lib with preserved RustPython markers and explicit migration deferrals. Include the published dependency-report fix from PR RustPython#8958, partial slot correction from PR RustPython#9127, and update_lib repair with existing-workflow coverage from PR RustPython#9131. Assisted-by: OpenAI Codex:model version unavailable

Preserve partial keyword identity through vectorcall

5cd074a

Retain keyword objects in CALL_FUNCTION_EX and snapshot partial state before Python callbacks. Match CPython 3.15 final partial keyword merging without changing Lib or tests. Assisted-by: OpenAI Codex:model version unavailable

youknowone marked this pull request as ready for review October 15, 2026 01:28

youknowone requested changes Oct 15, 2026

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coderabbitai Bot reviewed Oct 15, 2026

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Comment thread crates/vm/src/stdlib/_functools.rs Outdated

Register partial vectorcall through pyslot

b6c253d

Use the existing slot macro instead of a class extension hook. Return TypeError for non-string incoming names in the non-vectorcall fallback rather than panicking. Assisted-by: OpenAI Codex:model version unavailable

youknowone approved these changes Oct 15, 2026

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youknowone enabled auto-merge (squash) October 15, 2026 03:11

youknowdot mentioned this pull request Oct 15, 2026

Integrate remaining Python 3.15 final runtime and libraries #8954

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youknowone merged commit edb5ac4 into RustPython:main Oct 15, 2026
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Preserve partial keyword identity through vectorcall - #9127

Preserve partial keyword identity through vectorcall#9127
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