Handle paths with leading :: (root)

Remove the tons of `allow`s

Author: Centri3

CHANGELOG.md

@@ -4680,7 +4680,7 @@ Released 2018-09-13
 
 <!-- lint disable no-unused-definitions -->
 <!-- begin autogenerated links to lint list -->
-[`absolute_symbol_paths`]: https://rust-lang.github.io/rust-clippy/master/index.html#absolute_symbol_paths
+[`absolute_paths`]: https://rust-lang.github.io/rust-clippy/master/index.html#absolute_paths
 [`absurd_extreme_comparisons`]: https://rust-lang.github.io/rust-clippy/master/index.html#absurd_extreme_comparisons
 [`alloc_instead_of_core`]: https://rust-lang.github.io/rust-clippy/master/index.html#alloc_instead_of_core
 [`allow_attributes`]: https://rust-lang.github.io/rust-clippy/master/index.html#allow_attributes
@@ -5465,6 +5465,7 @@ Released 2018-09-13
 [`accept-comment-above-statement`]: https://doc.rust-lang.org/clippy/lint_configuration.html#accept-comment-above-statement
 [`accept-comment-above-attributes`]: https://doc.rust-lang.org/clippy/lint_configuration.html#accept-comment-above-attributes
 [`allow-one-hash-in-raw-strings`]: https://doc.rust-lang.org/clippy/lint_configuration.html#allow-one-hash-in-raw-strings
-[`absolute-symbol-paths-max-segments`]: https://doc.rust-lang.org/clippy/lint_configuration.html#absolute-symbol-paths-max-segments
-[`absolute-symbol-paths-allow-std`]: https://doc.rust-lang.org/clippy/lint_configuration.html#absolute-symbol-paths-allow-std
+[`absolute-paths-max-segments`]: https://doc.rust-lang.org/clippy/lint_configuration.html#absolute-paths-max-segments
+[`absolute-paths-allowed-crates`]: https://doc.rust-lang.org/clippy/lint_configuration.html#absolute-paths-allowed-crates
 <!-- end autogenerated links to configuration documentation -->
+iguration documentation -->

book/src/lint_configuration.md

@@ -730,20 +730,21 @@ Whether to allow `r#""#` when `r""` can be used
 * [`unnecessary_raw_string_hashes`](https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_raw_string_hashes)
 
 
-## `absolute-symbol-paths-max-segments`
-The maximum number of segments a path can have before being linted
+## `absolute-paths-max-segments`
+The maximum number of segments a path can have before being linted, anything above this will
+be linted.
 
-**Default Value:** `3` (`u64`)
+**Default Value:** `2` (`u64`)
 
 ---
 **Affected lints:**
 * [`absolute_symbol_paths`](https://rust-lang.github.io/rust-clippy/master/index.html#absolute_symbol_paths)
 
 
-## `absolute-symbol-paths-allow-std`
-Whether to allow paths originating from `core`/`std`/`alloc`
+## `absolute-paths-allowed-crates`
+Which crates to allow absolute paths from
 
-**Default Value:** `false` (`bool`)
+**Default Value:** `{}` (`rustc_data_structures::fx::FxHashSet<String>`)
 
 ---
 **Affected lints:**

clippy_lints/src/absolute_paths.rs

@@ -0,0 +1,100 @@
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::source::snippet_opt;
+use rustc_data_structures::fx::FxHashSet;
+use rustc_hir::def::{DefKind, Res};
+use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX};
+use rustc_hir::{HirId, ItemKind, Node, Path};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::symbol::kw;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for usage of items through absolute paths, like `std::env::current_dir`.
+    ///
+    /// ### Why is this bad?
+    /// Many codebases have their own style when it comes to importing, but one that is seldom used
+    /// is using absolute paths *everywhere*. This is generally considered unidiomatic, and you
+    /// should add a `use` statement.
+    ///
+    /// The default maximum segments (2) is pretty strict, you may want to increase this in
+    /// `clippy.toml`.
+    ///
+    /// Note: One exception to this is code from macro expansion - this does not lint such cases, as
+    /// using absolute paths is the proper way of referencing items in one.
+    ///
+    /// ### Example
+    /// ```rust
+    /// let x = std::f64::consts::PI;
+    /// ```
+    /// Use any of the below instead, or anything else:
+    /// ```rust
+    /// use std::f64;
+    /// use std::f64::consts;
+    /// use std::f64::consts::PI;
+    /// let x = f64::consts::PI;
+    /// let x = consts::PI;
+    /// let x = PI;
+    /// use std::f64::consts as f64_consts;
+    /// let x = f64_consts::PI;
+    /// ```
+    #[clippy::version = "1.73.0"]
+    pub ABSOLUTE_PATHS,
+    restriction,
+    "checks for usage of an item without a `use` statement"
+}
+impl_lint_pass!(AbsolutePaths => [ABSOLUTE_PATHS]);
+
+pub struct AbsolutePaths {
+    pub absolute_paths_max_segments: u64,
+    pub absolute_paths_allowed_crates: FxHashSet<String>,
+}
+
+impl LateLintPass<'_> for AbsolutePaths {
+    // We should only lint `QPath::Resolved`s, but since `Path` is only used in `Resolved` and `UsePath`
+    // we don't need to use a visitor or anything as we can just check if the `Node` for `hir_id` isn't
+    // a `Use`
+    #[expect(clippy::cast_possible_truncation)]
+    fn check_path(&mut self, cx: &LateContext<'_>, path: &Path<'_>, hir_id: HirId) {
+        let Self {
+            absolute_paths_max_segments,
+            absolute_paths_allowed_crates,
+        } = self;
+
+        if !path.span.from_expansion()
+            && let Some(node) = cx.tcx.hir().find(hir_id)
+            && !matches!(node, Node::Item(item) if matches!(item.kind, ItemKind::Use(_, _)))
+            && let [first, rest @ ..] = path.segments
+            // Handle `::std`
+            && let (segment, len) = if first.ident.name == kw::PathRoot {
+                // Indexing is fine as `PathRoot` must be followed by another segment. `len() - 1`
+                // is fine here for the same reason
+                (&rest[0], path.segments.len() - 1)
+            } else {
+                (first, path.segments.len())
+            }
+            && len > *absolute_paths_max_segments as usize
+            && let Some(segment_snippet) = snippet_opt(cx, segment.ident.span)
+            && segment_snippet == segment.ident.as_str()
+        {
+            let is_abs_external =
+                matches!(segment.res, Res::Def(DefKind::Mod, DefId { index, .. }) if index == CRATE_DEF_INDEX);
+            let is_abs_crate = segment.ident.name == kw::Crate;
+
+            if is_abs_external && absolute_paths_allowed_crates.contains(segment.ident.name.as_str())
+                || is_abs_crate && absolute_paths_allowed_crates.contains("crate")
+            {
+                return;
+            }
+
+            if is_abs_external || is_abs_crate {
+                span_lint(
+                    cx,
+                    ABSOLUTE_PATHS,
+                    path.span,
+                    "consider bringing this path into scope with the `use` keyword",
+                );
+            }
+        }
+    }
+}

clippy_lints/src/absolute_symbol_paths.rs

@@ -37,7 +37,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::utils::internal_lints::produce_ice::PRODUCE_ICE_INFO,
     #[cfg(feature = "internal")]
     crate::utils::internal_lints::unnecessary_def_path::UNNECESSARY_DEF_PATH_INFO,
-    crate::absolute_symbol_paths::ABSOLUTE_SYMBOL_PATHS_INFO,
+    crate::absolute_paths::ABSOLUTE_PATHS_INFO,
     crate::allow_attributes::ALLOW_ATTRIBUTES_INFO,
     crate::almost_complete_range::ALMOST_COMPLETE_RANGE_INFO,
     crate::approx_const::APPROX_CONSTANT_INFO,

clippy_lints/src/declared_lints.rs

@@ -10,11 +10,7 @@
 #![feature(stmt_expr_attributes)]
 #![recursion_limit = "512"]
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
-#![allow(
-    clippy::absolute_symbol_paths,
-    clippy::missing_docs_in_private_items,
-    clippy::must_use_candidate
-)]
+#![allow(clippy::missing_docs_in_private_items, clippy::must_use_candidate)]
 #![warn(trivial_casts, trivial_numeric_casts)]
 // warn on lints, that are included in `rust-lang/rust`s bootstrap
 #![warn(rust_2018_idioms, unused_lifetimes)]
@@ -69,7 +65,7 @@ mod declared_lints;
 mod renamed_lints;
 
 // begin lints modules, do not remove this comment, it’s used in `update_lints`
-mod absolute_symbol_paths;
+mod absolute_paths;
 mod allow_attributes;
 mod almost_complete_range;
 mod approx_const;
@@ -1085,12 +1081,12 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(move |_| Box::new(tuple_array_conversions::TupleArrayConversions { msrv: msrv() }));
     store.register_late_pass(|_| Box::new(manual_float_methods::ManualFloatMethods));
     store.register_late_pass(|_| Box::new(four_forward_slashes::FourForwardSlashes));
-    let absolute_symbol_paths_max_segments = conf.absolute_symbol_paths_max_segments;
-    let absolute_symbol_paths_allowed_crates = conf.absolute_symbol_paths_allowed_crates.clone();
+    let absolute_paths_max_segments = conf.absolute_paths_max_segments;
+    let absolute_paths_allowed_crates = conf.absolute_paths_allowed_crates.clone();
     store.register_late_pass(move |_| {
-        Box::new(absolute_symbol_paths::AbsoluteSymbolPaths {
-            absolute_symbol_paths_max_segments,
-            absolute_symbol_paths_allowed_crates: absolute_symbol_paths_allowed_crates.clone(),
+        Box::new(absolute_paths::AbsolutePaths {
+            absolute_paths_max_segments,
+            absolute_paths_allowed_crates: absolute_paths_allowed_crates.clone(),
         })
     });
     // add lints here, do not remove this comment, it's used in `new_lint`

clippy_lints/src/lib.rs

@@ -553,12 +553,13 @@ define_Conf! {
     (allow_one_hash_in_raw_strings: bool = false),
     /// Lint: ABSOLUTE_SYMBOL_PATHS.
     ///
-    /// The maximum number of segments a path can have before being linted
-    (absolute_symbol_paths_max_segments: u64 = 3),
+    /// The maximum number of segments a path can have before being linted, anything above this will
+    /// be linted.
+    (absolute_paths_max_segments: u64 = 2),
     /// Lint: ABSOLUTE_SYMBOL_PATHS.
     ///
-    /// Which crates to allow absolute symbols, `crate` will allow the local crate
-    (absolute_symbol_paths_allowed_crates: rustc_data_structures::fx::FxHashSet<String> =
+    /// Which crates to allow absolute paths from
+    (absolute_paths_allowed_crates: rustc_data_structures::fx::FxHashSet<String> =
         rustc_data_structures::fx::FxHashSet::default()),
 }
 

clippy_lints/src/utils/conf.rs

@@ -354,7 +354,7 @@ pub trait WithSearchPat<'cx> {
     fn span(&self) -> Span;
 }
 macro_rules! impl_with_search_pat {
-    ($cx:ident: $ty:ident with $fn:ident $(($tcx:ident))? && $span_method:ident$($par:tt)?) => {
+    ($cx:ident: $ty:ident with $fn:ident $(($tcx:ident))?) => {
         impl<'cx> WithSearchPat<'cx> for $ty<'cx> {
             type Context = $cx<'cx>;
             #[allow(unused_variables)]
@@ -363,19 +363,18 @@ macro_rules! impl_with_search_pat {
                 $fn($($tcx,)? self)
             }
             fn span(&self) -> Span {
-                self.$span_method$($par)?
+                self.span
             }
         }
     };
 }
-impl_with_search_pat!(LateContext: Expr with expr_search_pat(tcx) && span);
-impl_with_search_pat!(LateContext: Item with item_search_pat && span);
-impl_with_search_pat!(LateContext: TraitItem with trait_item_search_pat && span);
-impl_with_search_pat!(LateContext: ImplItem with impl_item_search_pat && span);
-impl_with_search_pat!(LateContext: FieldDef with field_def_search_pat && span);
-impl_with_search_pat!(LateContext: Variant with variant_search_pat && span);
-impl_with_search_pat!(LateContext: Ty with ty_search_pat && span);
-impl_with_search_pat!(LateContext: QPath with qpath_search_pat && span());
+impl_with_search_pat!(LateContext: Expr with expr_search_pat(tcx));
+impl_with_search_pat!(LateContext: Item with item_search_pat);
+impl_with_search_pat!(LateContext: TraitItem with trait_item_search_pat);
+impl_with_search_pat!(LateContext: ImplItem with impl_item_search_pat);
+impl_with_search_pat!(LateContext: FieldDef with field_def_search_pat);
+impl_with_search_pat!(LateContext: Variant with variant_search_pat);
+impl_with_search_pat!(LateContext: Ty with ty_search_pat);
 
 impl<'cx> WithSearchPat<'cx> for (&FnKind<'cx>, &Body<'cx>, HirId, Span) {
     type Context = LateContext<'cx>;

clippy_utils/src/check_proc_macro.rs

@@ -1,4 +1,3 @@
-#![allow(clippy::absolute_symbol_paths)]
 #![warn(clippy::self_named_module_files)]
 
 mod bad;

tests/ui-cargo/module_style/fail_mod/src/main.rs

@@ -1,10 +1,6 @@
 //@run-rustfix
 #![deny(clippy::internal)]
-#![allow(
-    clippy::absolute_symbol_paths,
-    clippy::missing_clippy_version_attribute,
-    clippy::let_unit_value
-)]
+#![allow(clippy::missing_clippy_version_attribute, clippy::let_unit_value)]
 #![feature(rustc_private)]
 
 extern crate rustc_span;

tests/ui-internal/interning_defined_symbol.fixed

@@ -1,10 +1,6 @@
 //@run-rustfix
 #![deny(clippy::internal)]
-#![allow(
-    clippy::absolute_symbol_paths,
-    clippy::missing_clippy_version_attribute,
-    clippy::let_unit_value
-)]
+#![allow(clippy::missing_clippy_version_attribute, clippy::let_unit_value)]
 #![feature(rustc_private)]
 
 extern crate rustc_span;