extend types and exceptions only for genesis by youknowone · Pull Request #7316 · RustPython/RustPython · GitHub

Summary by CodeRabbit

Refactor
- Tightened internal lifetime handling and unified how runtime components receive the global context.
- Moved type and exception population to the initial genesis step and removed duplicate late-stage population.
- Result: more consistent and reliable VM startup and steadier runtime state without changing user-facing APIs.

📝 Walkthrough

Walkthrough

Moved TypeZoo and ExceptionZoo extension into Context::genesis and changed many builtin init/extend APIs to accept a &'static Context; class construction now derives a &'static Context via an unsafe cast and uses that context's slot_new_wrapper when building bound new methods, with added safety comments.

Changes

Cohort / File(s)	Summary
Context & Initialization crates/vm/src/vm/context.rs, crates/vm/src/vm/interpreter.rs	TypeZoo::extend and ExceptionZoo::extend are now called inside Context::genesis; the interpreter no longer calls them at the previous initialization point.
Class construction & slot handling crates/vm/src/class.rs	PyClassImpl::extend_class/impl_extend_class now take &'static Context; make_class performs an unsafe cast to derive a &'static Context and uses ctx.slot_new_wrapper to construct a bound __new__ method; added lifetime/safety comments.
Derive codegen crates/derive-impl/src/pyclass.rs	Generated code for pyclass extension points changed to accept ctx: &'static ::rustpython_vm::Context (signatures updated).
Exception & Type zoos crates/vm/src/exceptions.rs, crates/vm/src/types/zoo.rs	extend functions now require &'static Context; TypeZoo/ExceptionZoo signatures updated to static Context.
Builtins init signatures (many files) crates/vm/src/builtins/... (e.g., bool.rs, bytes.rs, list.rs, dict.rs, function.rs, type.rs, ... )	Numerous builtin init functions' ctx/context parameter changed from &Context to &'static Context, adjusting call-site lifetime requirements across builtin initializers.
Stdlib typing init crates/vm/src/stdlib/typing.rs	pub fn init(ctx: &Context) → pub fn init(ctx: &'static Context) to match the updated lifetime usage.

Sequence Diagram(s)

sequenceDiagram
    participant Genesis as Context::genesis
    participant TypeZoo as TypeZoo
    participant ExceptionZoo as ExceptionZoo
    participant MakeClass as make_class / extend_class
    participant Builtin as builtin::init

    Genesis->>TypeZoo: TypeZoo::extend(&ctx)
    Genesis->>ExceptionZoo: ExceptionZoo::extend(&ctx)
    Note right of Genesis: genesis returns Context (now populated)
    Builtin->>MakeClass: call make_class(ctx)
    MakeClass->>MakeClass: unsafe cast ctx -> &'static Context
    MakeClass->>MakeClass: use ctx.slot_new_wrapper to build bound __new__

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

Upgrade typing from 3.14.2 and more impl #7057: touches TypeZoo and initialization ordering (strong overlap with moving zoos into genesis).
Add _types module #6807: related changes to builtins/type initialization and Context usage.
Introduce slot wrapper to __init__ #4884: previously introduced slot/method wrapper registration and relates to slot_new_wrapper handling.

Suggested reviewers

ShaharNaveh
coolreader18

Poem

"I nibble through the genesis day,
Zoos awaken, slots at play,
I hop and bind a new-born new,
With careful cast and wartime chew,
A happy rabbit bakes this change today 🐇"

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 24.21% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'extend types and exceptions only for genesis' accurately describes the main change: moving TypeZoo and ExceptionZoo initialization from VM setup to Context genesis creation.

✏️ Tip: You can configure your own custom pre-merge checks in the settings.

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Code has been automatically formatted

The code in this PR has been formatted using:

cargo fmt --all
Please pull the latest changes before pushing again:

git pull origin genesis-extend

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@crates/vm/src/class.rs`:
- Around line 191-196: The unsafe cast to &'static PyMethodDef (using
ctx.slot_new_wrapper) is unsound because extend_class takes ctx: &Context;
change the trait signature to require static lifetimes (e.g., fn
extend_class(ctx: &'static Context, class: &'static Py<PyType>)) so the compiler
encodes the invariant, update all impls/call sites accordingly, then remove the
unsafe &'static cast and use wrapper = &ctx.slot_new_wrapper directly (or keep
wrapper as &'static if callers now supply &'static Context); reference symbols:
extend_class, Context, ctx.slot_new_wrapper, PyMethodDef, build_bound_method,
and class.set_attr to locate and modify the code.

ℹ️ Review info

Configuration used: Path: .coderabbit.yml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 0a6a6f8 and 050ca62.

📒 Files selected for processing (3)

crates/vm/src/class.rs
crates/vm/src/vm/context.rs
crates/vm/src/vm/interpreter.rs

💤 Files with no reviewable changes (1)

crates/vm/src/vm/interpreter.rs

♻️ Duplicate comments (1)

crates/vm/src/class.rs (1)

209-217: ⚠️ Potential issue | 🔴 Critical

make_class still allows non-static input before forcing 'static via unsafe cast.

Line 217 casts &Context to &'static Context, but Line 209 still accepts any borrowed context. If a non-genesis context reaches this path, this is undefined behavior.

Suggested fix

-    fn make_class(ctx: &Context) -> PyTypeRef
+    fn make_class(ctx: &'static Context) -> PyTypeRef
     where
         Self: StaticType + Sized,
     {
         (*Self::static_cell().get_or_init(|| {
             let typ = Self::create_static_type();
-            // SAFETY: Context is heap-allocated via PyRc and stored in a static cell
-            // (Context::genesis), so it lives for 'static.
-            let ctx: &'static Context = unsafe { &*(ctx as *const Context) };
             Self::extend_class(ctx, unsafe {
                 // typ will be saved in static_cell
                 let r: &Py<PyType> = &typ;

#!/bin/bash
set -euo pipefail

echo "== Check make_class signature and unsafe cast =="
rg -nP --type=rust -C2 'fn\s+make_class\s*\(\s*ctx:\s*&Context\s*\)|unsafe\s*\{\s*&\*\(ctx as \*const Context\)\s*\}' crates/vm/src/class.rs

echo
echo "== List make_class call sites =="
rg -nP --type=rust -C2 '\bmake_class\s*\('

echo
echo "== Inspect Context construction/entrypoints =="
rg -nP --type=rust -C3 'impl\s+Context|fn\s+genesis\s*\(|fn\s+new\s*\(' crates/vm/src/vm/context.rs

As per coding guidelines "Follow Rust best practices for error handling and memory management".

ℹ️ Review info

Configuration used: Path: .coderabbit.yml

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 8df31f9 and 072c495.

📒 Files selected for processing (53)

crates/derive-impl/src/pyclass.rs
crates/vm/src/builtins/asyncgenerator.rs
crates/vm/src/builtins/bool.rs
crates/vm/src/builtins/builtin_func.rs
crates/vm/src/builtins/bytearray.rs
crates/vm/src/builtins/bytes.rs
crates/vm/src/builtins/capsule.rs
crates/vm/src/builtins/classmethod.rs
crates/vm/src/builtins/code.rs
crates/vm/src/builtins/complex.rs
crates/vm/src/builtins/coroutine.rs
crates/vm/src/builtins/descriptor.rs
crates/vm/src/builtins/dict.rs
crates/vm/src/builtins/enumerate.rs
crates/vm/src/builtins/filter.rs
crates/vm/src/builtins/float.rs
crates/vm/src/builtins/frame.rs
crates/vm/src/builtins/function.rs
crates/vm/src/builtins/generator.rs
crates/vm/src/builtins/genericalias.rs
crates/vm/src/builtins/getset.rs
crates/vm/src/builtins/int.rs
crates/vm/src/builtins/interpolation.rs
crates/vm/src/builtins/iter.rs
crates/vm/src/builtins/list.rs
crates/vm/src/builtins/map.rs
crates/vm/src/builtins/mappingproxy.rs
crates/vm/src/builtins/memory.rs
crates/vm/src/builtins/module.rs
crates/vm/src/builtins/namespace.rs
crates/vm/src/builtins/object.rs
crates/vm/src/builtins/property.rs
crates/vm/src/builtins/range.rs
crates/vm/src/builtins/set.rs
crates/vm/src/builtins/singletons.rs
crates/vm/src/builtins/slice.rs
crates/vm/src/builtins/staticmethod.rs
crates/vm/src/builtins/str.rs
crates/vm/src/builtins/super.rs
crates/vm/src/builtins/template.rs
crates/vm/src/builtins/traceback.rs
crates/vm/src/builtins/tuple.rs
crates/vm/src/builtins/type.rs
crates/vm/src/builtins/union.rs
crates/vm/src/builtins/weakproxy.rs
crates/vm/src/builtins/weakref.rs
crates/vm/src/builtins/zip.rs
crates/vm/src/class.rs
crates/vm/src/exceptions.rs
crates/vm/src/stdlib/typing.rs
crates/vm/src/types/zoo.rs
crates/vm/src/vm/context.rs
crates/vm/src/vm/interpreter.rs

💤 Files with no reviewable changes (1)

crates/vm/src/vm/interpreter.rs

🚧 Files skipped from review as they are similar to previous changes (1)

crates/vm/src/vm/context.rs

youknowone force-pushed the genesis-extend branch from f77c40a to a0692d3 Compare March 2, 2026 12:03

youknowone marked this pull request as ready for review March 3, 2026 00:05

coderabbitai Bot reviewed Mar 3, 2026

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Comment thread crates/vm/src/class.rs Outdated

youknowone force-pushed the genesis-extend branch from 050ca62 to a0692d3 Compare March 3, 2026 00:34

youknowone added 2 commits March 3, 2026 10:17

extend types only for genesis

07f2ecc

'static

072c495

youknowone force-pushed the genesis-extend branch from 8df31f9 to 072c495 Compare March 3, 2026 01:17

coderabbitai Bot reviewed Mar 3, 2026

View reviewed changes

youknowone merged commit 1f6e47c into RustPython:main Mar 3, 2026
13 checks passed

youknowone deleted the genesis-extend branch March 3, 2026 02:24

coderabbitai Bot mentioned this pull request Mar 3, 2026

make_class -> make_static_type #7331

Merged

youknowone added a commit to youknowone/RustPython that referenced this pull request Mar 22, 2026

extend types and exceptions only for genesis (RustPython#7316 )

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extend types and exceptions only for genesis by youknowone · Pull Request #7316 · RustPython/RustPython · GitHub

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extend types and exceptions only for genesis - #7316

extend types and exceptions only for genesis#7316
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extend types and exceptions only for genesis by youknowone · Pull Request #7316 · RustPython/RustPython · GitHub

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extend types and exceptions only for genesis - #7316

extend types and exceptions only for genesis#7316youknowone merged 2 commits intoRustPython:mainRustPython/RustPython:mainfrom youknowone:genesis-extendyouknowone/RustPython:genesis-extendCopy head branch name to clipboard

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Walkthrough

Changes

Sequence Diagram(s)

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Possibly related PRs

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extend types and exceptions only for genesis#7316
youknowone merged 2 commits into
RustPython:mainfrom
youknowone:genesis-extend

youknowone commented Mar 2, 2026 •
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