Deserialize Msrv directly in Conf

book/src/lint_configuration.md

@@ -100,7 +100,7 @@ Suppress lints whenever the suggested change would cause breakage for other crat
 ## `msrv`
 The minimum rust version that the project supports
 
-**Default Value:** `None` (`Option<String>`)
+**Default Value:** `Msrv { stack: [] }` (`crate::Msrv`)
 
 ---
 **Affected lints:**

clippy_lints/src/lib.rs

@@ -50,9 +50,6 @@ extern crate clippy_utils;
 #[macro_use]
 extern crate declare_clippy_lint;
 
-use std::io;
-use std::path::PathBuf;
-
 use clippy_utils::msrvs::Msrv;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_lint::{Lint, LintId};
@@ -362,7 +359,6 @@ mod zero_sized_map_values;
 // end lints modules, do not remove this comment, it’s used in `update_lints`
 
 use crate::utils::conf::metadata::get_configuration_metadata;
-use crate::utils::conf::TryConf;
 pub use crate::utils::conf::{lookup_conf_file, Conf};
 use crate::utils::FindAll;
 
@@ -374,65 +370,13 @@ use crate::utils::FindAll;
 /// level (i.e `#![cfg_attr(...)]`) will still be expanded even when using a pre-expansion pass.
 ///
 /// Used in `./src/driver.rs`.
-pub fn register_pre_expansion_lints(store: &mut rustc_lint::LintStore, sess: &Session, conf: &Conf) {
+pub fn register_pre_expansion_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
     // NOTE: Do not add any more pre-expansion passes. These should be removed eventually.
-    let msrv = Msrv::read(&conf.msrv, sess);
-    let msrv = move || msrv.clone();
+    let msrv = || conf.msrv.clone();
 
     store.register_pre_expansion_pass(move || Box::new(attrs::EarlyAttributes { msrv: msrv() }));
 }
 
-#[doc(hidden)]
-pub fn read_conf(sess: &Session, path: &io::Result<(Option<PathBuf>, Vec<String>)>) -> Conf {
-    if let Ok((_, warnings)) = path {
-        for warning in warnings {
-            sess.warn(warning.clone());
-        }
-    }
-    let file_name = match path {
-        Ok((Some(path), _)) => path,
-        Ok((None, _)) => return Conf::default(),
-        Err(error) => {
-            sess.err(format!("error finding Clippy's configuration file: {error}"));
-            return Conf::default();
-        },
-    };
-
-    let TryConf { conf, errors, warnings } = utils::conf::read(sess, file_name);
-    // all conf errors are non-fatal, we just use the default conf in case of error
-    for error in errors {
-        if let Some(span) = error.span {
-            sess.span_err(
-                span,
-                format!("error reading Clippy's configuration file: {}", error.message),
-            );
-        } else {
-            sess.err(format!(
-                "error reading Clippy's configuration file `{}`: {}",
-                file_name.display(),
-                error.message
-            ));
-        }
-    }
-
-    for warning in warnings {
-        if let Some(span) = warning.span {
-            sess.span_warn(
-                span,
-                format!("error reading Clippy's configuration file: {}", warning.message),
-            );
-        } else {
-            sess.warn(format!(
-                "error reading Clippy's configuration file `{}`: {}",
-                file_name.display(),
-                warning.message
-            ));
-        }
-    }
-
-    conf
-}
-
 #[derive(Default)]
 struct RegistrationGroups {
     all: Vec<LintId>,
@@ -558,7 +502,7 @@ fn register_categories(store: &mut rustc_lint::LintStore) {
 ///
 /// Used in `./src/driver.rs`.
 #[expect(clippy::too_many_lines)]
-pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &Conf) {
+pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &'static Conf) {
     register_removed_non_tool_lints(store);
     register_categories(store);
 
@@ -660,8 +604,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(|_| Box::new(non_octal_unix_permissions::NonOctalUnixPermissions));
     store.register_early_pass(|| Box::new(unnecessary_self_imports::UnnecessarySelfImports));
 
-    let msrv = Msrv::read(&conf.msrv, sess);
-    let msrv = move || msrv.clone();
+    let msrv = || conf.msrv.clone();
     let avoid_breaking_exported_api = conf.avoid_breaking_exported_api;
     let allow_expect_in_tests = conf.allow_expect_in_tests;
     let allow_unwrap_in_tests = conf.allow_unwrap_in_tests;

clippy_lints/src/matches/mod.rs

@@ -967,7 +967,6 @@ declare_clippy_lint! {
     "checks for unnecessary guards in match expressions"
 }
 
-#[derive(Default)]
 pub struct Matches {
     msrv: Msrv,
     infallible_destructuring_match_linted: bool,
@@ -978,7 +977,7 @@ impl Matches {
     pub fn new(msrv: Msrv) -> Self {
         Self {
             msrv,
-            ..Matches::default()
+            infallible_destructuring_match_linted: false,
         }
     }
 }

clippy_lints/src/use_self.rs

@@ -54,7 +54,6 @@ declare_clippy_lint! {
     "unnecessary structure name repetition whereas `Self` is applicable"
 }
 
-#[derive(Default)]
 pub struct UseSelf {
     msrv: Msrv,
     stack: Vec<StackItem>,
@@ -65,7 +64,7 @@ impl UseSelf {
     pub fn new(msrv: Msrv) -> Self {
         Self {
             msrv,
-            ..Self::default()
+            stack: Vec::new(),
         }
     }
 }

clippy_lints/src/utils/conf.rs

@@ -8,8 +8,9 @@ use serde::de::{Deserializer, IgnoredAny, IntoDeserializer, MapAccess, Visitor};
 use serde::Deserialize;
 use std::fmt::{Debug, Display, Formatter};
 use std::ops::Range;
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 use std::str::FromStr;
+use std::sync::OnceLock;
 use std::{cmp, env, fmt, fs, io};
 
 #[rustfmt::skip]
@@ -78,62 +79,35 @@ pub struct TryConf {
 
 impl TryConf {
     fn from_toml_error(file: &SourceFile, error: &toml::de::Error) -> Self {
-        ConfError::from_toml(file, error).into()
-    }
-}
-
-impl From<ConfError> for TryConf {
-    fn from(value: ConfError) -> Self {
         Self {
             conf: Conf::default(),
-            errors: vec![value],
+            errors: vec![ConfError::from_toml(file, error)],
             warnings: vec![],
         }
     }
 }
 
-impl From<io::Error> for TryConf {
-    fn from(value: io::Error) -> Self {
-        ConfError::from(value).into()
-    }
-}
-
 #[derive(Debug)]
 pub struct ConfError {
     pub message: String,
-    pub span: Option<Span>,
+    pub span: Span,
 }
 
 impl ConfError {
     fn from_toml(file: &SourceFile, error: &toml::de::Error) -> Self {
-        if let Some(span) = error.span() {
-            Self::spanned(file, error.message(), span)
-        } else {
-            Self {
-                message: error.message().to_string(),
-                span: None,
-            }
-        }
+        let span = error.span().unwrap_or(0..file.source_len.0 as usize);
+        Self::spanned(file, error.message(), span)
     }
 
     fn spanned(file: &SourceFile, message: impl Into<String>, span: Range<usize>) -> Self {
         Self {
             message: message.into(),
-            span: Some(Span::new(
+            span: Span::new(
                 file.start_pos + BytePos::from_usize(span.start),
                 file.start_pos + BytePos::from_usize(span.end),
                 SyntaxContext::root(),
                 None,
-            )),
-        }
-    }
-}
-
-impl From<io::Error> for ConfError {
-    fn from(value: io::Error) -> Self {
-        Self {
-            message: value.to_string(),
-            span: None,
+            ),
         }
     }
 }
@@ -297,7 +271,7 @@ define_Conf! {
     /// Lint: MANUAL_SPLIT_ONCE, MANUAL_STR_REPEAT, CLONED_INSTEAD_OF_COPIED, REDUNDANT_FIELD_NAMES, OPTION_MAP_UNWRAP_OR, REDUNDANT_STATIC_LIFETIMES, FILTER_MAP_NEXT, CHECKED_CONVERSIONS, MANUAL_RANGE_CONTAINS, USE_SELF, MEM_REPLACE_WITH_DEFAULT, MANUAL_NON_EXHAUSTIVE, OPTION_AS_REF_DEREF, MAP_UNWRAP_OR, MATCH_LIKE_MATCHES_MACRO, MANUAL_STRIP, MISSING_CONST_FOR_FN, UNNESTED_OR_PATTERNS, FROM_OVER_INTO, PTR_AS_PTR, IF_THEN_SOME_ELSE_NONE, APPROX_CONSTANT, DEPRECATED_CFG_ATTR, INDEX_REFUTABLE_SLICE, MAP_CLONE, BORROW_AS_PTR, MANUAL_BITS, ERR_EXPECT, CAST_ABS_TO_UNSIGNED, UNINLINED_FORMAT_ARGS, MANUAL_CLAMP, MANUAL_LET_ELSE, UNCHECKED_DURATION_SUBTRACTION, COLLAPSIBLE_STR_REPLACE, SEEK_FROM_CURRENT, SEEK_REWIND, UNNECESSARY_LAZY_EVALUATIONS, TRANSMUTE_PTR_TO_REF, ALMOST_COMPLETE_RANGE, NEEDLESS_BORROW, DERIVABLE_IMPLS, MANUAL_IS_ASCII_CHECK, MANUAL_REM_EUCLID, MANUAL_RETAIN, TYPE_REPETITION_IN_BOUNDS, TUPLE_ARRAY_CONVERSIONS, MANUAL_TRY_FOLD, MANUAL_HASH_ONE.
     ///
     /// The minimum rust version that the project supports
-    (msrv: Option<String> = None),
+    (msrv: crate::Msrv = crate::Msrv::empty()),
     /// DEPRECATED LINT: BLACKLISTED_NAME.
     ///
     /// Use the Disallowed Names lint instead
@@ -641,15 +615,8 @@ pub fn lookup_conf_file() -> io::Result<(Option<PathBuf>, Vec<String>)> {
     }
 }
 
-/// Read the `toml` configuration file.
-///
-/// In case of error, the function tries to continue as much as possible.
-pub fn read(sess: &Session, path: &Path) -> TryConf {
-    let file = match sess.source_map().load_file(path) {
-        Err(e) => return e.into(),
-        Ok(file) => file,
-    };
-    match toml::de::Deserializer::new(file.src.as_ref().unwrap()).deserialize_map(ConfVisitor(&file)) {
+fn deserialize(file: &SourceFile) -> TryConf {
+    match toml::de::Deserializer::new(file.src.as_ref().unwrap()).deserialize_map(ConfVisitor(file)) {
         Ok(mut conf) => {
             extend_vec_if_indicator_present(&mut conf.conf.doc_valid_idents, DEFAULT_DOC_VALID_IDENTS);
             extend_vec_if_indicator_present(&mut conf.conf.disallowed_names, DEFAULT_DISALLOWED_NAMES);
@@ -662,7 +629,7 @@ pub fn read(sess: &Session, path: &Path) -> TryConf {
 
             conf
         },
-        Err(e) => TryConf::from_toml_error(&file, &e),
+        Err(e) => TryConf::from_toml_error(file, &e),
     }
 }
 
@@ -672,6 +639,60 @@ fn extend_vec_if_indicator_present(vec: &mut Vec<String>, default: &[&str]) {
     }
 }
 
+impl Conf {
+    pub fn read(sess: &Session, path: &io::Result<(Option<PathBuf>, Vec<String>)>) -> &'static Conf {
+        static CONF: OnceLock<Conf> = OnceLock::new();
+        CONF.get_or_init(|| Conf::read_inner(sess, path))
+    }
+
+    fn read_inner(sess: &Session, path: &io::Result<(Option<PathBuf>, Vec<String>)>) -> Conf {
+        match path {
+            Ok((_, warnings)) => {
+                for warning in warnings {
+                    sess.warn(warning.clone());
+                }
+            },
+            Err(error) => {
+                sess.err(format!("error finding Clippy's configuration file: {error}"));
+            },
+        }
+
+        let TryConf {
+            mut conf,
+            errors,
+            warnings,
+        } = match path {
+            Ok((Some(path), _)) => match sess.source_map().load_file(path) {
+                Ok(file) => deserialize(&file),
+                Err(error) => {
+                    sess.err(format!("failed to read `{}`: {error}", path.display()));
+                    TryConf::default()
+                },
+            },
+            _ => TryConf::default(),
+        };
+
+        conf.msrv.read_cargo(sess);
+
+        // all conf errors are non-fatal, we just use the default conf in case of error
+        for error in errors {
+            sess.span_err(
+                error.span,
+                format!("error reading Clippy's configuration file: {}", error.message),
+            );
+        }
+
+        for warning in warnings {
+            sess.span_warn(
+                warning.span,
+                format!("error reading Clippy's configuration file: {}", warning.message),
+            );
+        }
+
+        conf
+    }
+}
+
 const SEPARATOR_WIDTH: usize = 4;
 
 #[derive(Debug)]

clippy_utils/Cargo.toml

@@ -9,6 +9,7 @@ arrayvec = { version = "0.7", default-features = false }
 if_chain = "1.0"
 itertools = "0.10.1"
 rustc-semver = "1.1"
+serde = { version = "1.0" }
 
 [features]
 deny-warnings = []