no_std clippy by youknowone · Pull Request #7043 · RustPython/RustPython

youknowone

📝 Walkthrough

Walkthrough

This PR enables additional Clippy lints and systematically replaces many std:: usages with core:: and alloc:: equivalents across the codebase (memory, pointers, atomics, collections, FFI and threading types) to align with no-std/no-std-like constraints.

Changes

Cohort / File(s)	Summary
Clippy Configuration `Cargo.toml`	Uncommented/enabled clippy lints: `alloc_instead_of_core`, `std_instead_of_alloc`, `std_instead_of_core`; added `suspicious` and `correctness` lint groups set to `warn`.
Memory & Pointer core:: Migration `crates/.../codegen/src/compile.rs`, `crates/common/src/crt_fd.rs`, `crates/common/src/fileutils.rs`, `crates/stdlib/src/mmap.rs`, `crates/vm/src/stdlib/nt.rs`, `crates/vm/src/stdlib/sys.rs`, `crates/vm/src/windows.rs`, `crates/vm/src/stdlib/winapi.rs`, `crates/vm/src/stdlib/winreg.rs`	Replaced `std::mem::`, `std::ptr::`, `std::mem::MaybeUninit`, `std::mem::zeroed`, and `std::mem::size_of*` usages with `core::` equivalents for initialization, sizing, and null pointers.
Slices / Iterators / Formatting Migration `crates/stdlib/src/_sqlite3.rs`, `crates/stdlib/src/math.rs`, `crates/stdlib/src/socket.rs`, `crates/stdlib/src/ssl.rs`, `crates/vm/src/stdlib/io.rs`, `crates/vm/src/stdlib/msvcrt.rs`	Swapped `std::slice`, `std::iter`, `std::fmt` and related calls with `core::slice`, `core::iter`, `core::fmt` equivalents (including Debug impl updates).
Atomic Types Migration `crates/stdlib/src/_asyncio.rs`, `crates/stdlib/src/posixsubprocess.rs`, `crates/vm/src/builtins/template.rs`, `crates/vm/src/stdlib/_abc.rs`, `crates/vm/src/stdlib/signal.rs`, `crates/vm/src/vm/interpreter.rs`, `crates/vm/src/vm/mod.rs`	Replaced `std::sync::atomic::{...}` imports and usages with `core::sync::atomic` counterparts; updated struct fields/initializers and Ordering references (notably `PyTemplateIter` fields).
Arc/Weak & Collections Migration `crates/stdlib/src/multiprocessing.rs`, `crates/stdlib/src/overlapped.rs`, `crates/stdlib/src/thread.rs`, `crates/vm/src/vm/thread.rs`, `crates/vm/src/vm/interpreter.rs`, `crates/vm/src/vm/mod.rs`	Replaced `std::sync::Arc`/`Weak` with `alloc::sync::{Arc, Weak}` and moved `std::collections::BTreeMap` uses to `alloc::collections::BTreeMap`/local imports; several public struct fields/types updated accordingly (thread-related types).
FFI / CString / c_void Migration `crates/common/src/fileutils.rs`, `crates/stdlib/src/multiprocessing.rs`, `crates/stdlib/src/os.rs`, `crates/vm/src/stdlib/ctypes.rs`	Replaced `std::ffi::CString` with `alloc::ffi::CString` in allocation contexts; switched `std::ffi::c_void` to `core::ffi::c_void` in function-pointer signatures.
Duration / Time types Migration `crates/stdlib/src/ssl.rs`, `crates/vm/src/stdlib/time.rs`	Replaced `std::time::Duration` with `core::time::Duration` in function parameters/usage and corresponding duration computations.
Clippy allow attributes & minor annotations `crates/vm/src/stdlib/ctypes/base.rs`, `crates/vm/src/stdlib/ctypes/function.rs`, `crates/vm/src/stdlib/ctypes/pointer.rs`, `crates/vm/src/stdlib/ctypes/simple.rs`, `crates/vm/src/stdlib/io.rs`	Added/expanded clippy allow attributes (e.g., `clippy::useless_conversion`, `clippy::unnecessary_cast`) with reason strings for platform-specific wchar_t conversions and added small comment/lint tweaks.
Small std→core/alloc swaps in VM internals `crates/vm/src/builtins/function.rs`, `crates/vm/src/builtins/tuple.rs`, `crates/vm/src/frame.rs`, `crates/vm/src/signal.rs`, `crates/vm/src/builtins/template.rs`, `crates/vm/src/stdlib/ctypes/*`, `crates/vm/src/stdlib/io.rs`, `crates/vm/src/stdlib/msvcrt.rs`	Replaced scattered `std::` usages (e.g., `mem::take`, `mem::replace`, `hint::unreachable_unchecked`, `cell::Cell`, `ptr::null_mut`) with `core::` equivalents; atomic and field signature adjustments where applicable.

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~75 minutes

Possibly related PRs

finish no_std clippy #6587: Similar no-std/core+alloc migration across many stdlib modules (strong overlap in approach and affected files).
Fix asyncio related compiler/library issues #6837: Touches crates/codegen/src/compile.rs and may conflict with changes around t-string/template handling.
Upgrade threading to 3.13.11; sys.setprofile & impl more threading #6691: Changes threading types/APIs (ThreadHandle/ShutdownEntry/Arc/Weak) similar to the thread-related type migrations here.

Suggested reviewers

ShaharNaveh
arihant2math

"🐰 I hopped through code at break of dawn,
Swapped std for core before the lawn,
Pointers neat and atomics bright,
Clippy nods as I take flight —
A tiny hop, a cleaner night."

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Title check	❓ Inconclusive	The title 'no_std clippy' is vague and generic, using non-descriptive terms that don't clearly convey the changeset's main objective despite referencing a related initiative.	Revise the title to be more specific and descriptive of the primary changes, such as 'Replace std library imports with core/alloc equivalents for no_std compatibility' or reference the issue more explicitly.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Docstring Coverage	✅ Passed	Docstring coverage is 96.75% which is sufficient. The required threshold is 80.00%.

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