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Auto merge of #13472 - GnomedDev:smaller-msrv, r=Jarcho

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Optimise Msrv for common one item case

Currently, `Msrv` is cloned around a lot in order to handle the `#[clippy::msrv]` attribute. This attribute, however, means `RustcVersion` will be heap allocated if there is only one source of an msrv (eg: `rust-version` in `Cargo.toml`).

This PR optimizes for said case, while keeping the external interface the same by swapping the internal representation to `SmallVec<[RustcVersion; 2]>`.

changelog: none
This commit is contained in:
bors 2024-10-28 12:53:06 +00:00
commit a529c44eca
2 changed files with 6 additions and 4 deletions
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1
clippy_config/src/lib.rs
View File

@ -20,6 +20,7 @@ extern crate rustc_driver;
extern crate rustc_errors;
extern crate rustc_session;
extern crate rustc_span;
extern crate smallvec;
mod conf;
mod metadata;

9
clippy_config/src/msrvs.rs
View File

@ -3,6 +3,7 @@ use rustc_attr::parse_version;
use rustc_session::{RustcVersion, Session};
use rustc_span::{Symbol, sym};
use serde::Deserialize;
use smallvec::{SmallVec, smallvec};
use std::fmt;
macro_rules! msrv_aliases {
@ -67,7 +68,7 @@ msrv_aliases! {
/// Tracks the current MSRV from `clippy.toml`, `Cargo.toml` or set via `#[clippy::msrv]`
#[derive(Debug, Clone)]
pub struct Msrv {
stack: Vec<RustcVersion>,
stack: SmallVec<[RustcVersion; 2]>,
}
impl fmt::Display for Msrv {
@ -87,14 +88,14 @@ impl<'de> Deserialize<'de> for Msrv {
{
let v = String::deserialize(deserializer)?;
parse_version(Symbol::intern(&v))
.map(|v| Msrv { stack: vec![v] })
.map(|v| Msrv { stack: smallvec![v] })
.ok_or_else(|| serde::de::Error::custom("not a valid Rust version"))
}
}
impl Msrv {
pub fn empty() -> Msrv {
Msrv { stack: Vec::new() }
Msrv { stack: SmallVec::new() }
}
pub fn read_cargo(&mut self, sess: &Session) {
@ -103,7 +104,7 @@ impl Msrv {
.and_then(|v| parse_version(Symbol::intern(&v)));
match (self.current(), cargo_msrv) {
(None, Some(cargo_msrv)) => self.stack = vec![cargo_msrv],
(None, Some(cargo_msrv)) => self.stack = smallvec![cargo_msrv],
(Some(clippy_msrv), Some(cargo_msrv)) => {
if clippy_msrv != cargo_msrv {
sess.dcx().warn(format!(