Add configuration options

Author: Centri3

CHANGELOG.md

@@ -5422,4 +5422,6 @@ 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
 <!-- end autogenerated links to configuration documentation -->

book/src/lint_configuration.md

@@ -729,3 +729,23 @@ 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 max number of segments a path can have before being linted
+
+**Default Value:** `3` (`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`
+
+**Default Value:** `false` (`bool`)
+
+---
+**Affected lints:**
+* [`absolute_symbol_paths`](https://rust-lang.github.io/rust-clippy/master/index.html#absolute_symbol_paths)
+
+

clippy_lints/src/absolute_symbol_paths.rs

@@ -1,11 +1,12 @@
 use clippy_utils::diagnostics::span_lint;
 use clippy_utils::is_from_proc_macro;
 use rustc_hir::intravisit::{walk_qpath, Visitor};
-use rustc_hir::{HirId, QPath};
+use rustc_hir::{def_id::LOCAL_CRATE, HirId, QPath};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::nested_filter::OnlyBodies;
-use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::Span;
+use std::iter::once;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -39,16 +40,32 @@ declare_clippy_lint! {
     style,
     "checks for usage of a symbol without a `use` statement"
 }
-declare_lint_pass!(AbsoluteSymbolPaths => [ABSOLUTE_SYMBOL_PATHS]);
+impl_lint_pass!(AbsoluteSymbolPaths => [ABSOLUTE_SYMBOL_PATHS]);
+
+pub struct AbsoluteSymbolPaths {
+    pub absolute_symbol_paths_max_segments: u64,
+    pub absolute_symbol_paths_allow_std: bool,
+}
 
 impl LateLintPass<'_> for AbsoluteSymbolPaths {
     fn check_crate(&mut self, cx: &LateContext<'_>) {
-        cx.tcx.hir().visit_all_item_likes_in_crate(&mut V { cx });
+        let Self {
+            absolute_symbol_paths_max_segments,
+            absolute_symbol_paths_allow_std,
+        } = *self;
+
+        cx.tcx.hir().visit_all_item_likes_in_crate(&mut V {
+            cx,
+            absolute_symbol_paths_max_segments,
+            absolute_symbol_paths_allow_std,
+        });
     }
 }
 
 struct V<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
+    absolute_symbol_paths_max_segments: u64,
+    absolute_symbol_paths_allow_std: bool,
 }
 
 impl<'a, 'tcx> Visitor<'tcx> for V<'a, 'tcx> {
@@ -58,29 +75,43 @@ impl<'a, 'tcx> Visitor<'tcx> for V<'a, 'tcx> {
         self.cx.tcx.hir()
     }
 
+    #[expect(clippy::cast_possible_truncation)]
     fn visit_qpath(&mut self, qpath: &'tcx QPath<'tcx>, hir_id: HirId, span: Span) {
-        let Self { cx } = *self;
+        let Self {
+            cx,
+            absolute_symbol_paths_max_segments,
+            absolute_symbol_paths_allow_std,
+        } = *self;
 
         if !span.from_expansion()
             && let QPath::Resolved(_, path) = qpath
             && let Some(def_id) = path.res.opt_def_id()
+            && let def_path = cx.tcx.def_path(def_id)
+            && let crate_name = cx.tcx.crate_name(def_path.krate)
+            && let segments = once(crate_name)
+                .chain(def_path.data.iter().filter_map(|segment| segment.data.get_opt_name()))
+            && path.segments.len() > absolute_symbol_paths_max_segments as usize
+            && let is_std = matches!(crate_name.as_str(), "alloc" | "core" | "std")
+            && !(absolute_symbol_paths_allow_std && is_std)
+            // If this is local, keep the crate name, if it is not, remove it, as we don't need to
+            // check that (and results in FNs on reexports from one crate to another)
+            //
+            // `def_path_str` handles this for us, but unfortunately requires converting every
+            // `Symbol` to a `&str`, which is a very slow operation.
+            && segments.skip(1).eq(
+                path.segments.iter()
+                    // I love clippy :)
+                    .skip(usize::from(def_path.krate != LOCAL_CRATE))
+                    .map(|segment| segment.ident.name)
+                )
+            && !is_from_proc_macro(cx, qpath)
         {
-            let def_path = cx.tcx.def_path_str(def_id);
-            let segments = def_path.split("::");
-
-            // FIXME: I only allowed 3 segment paths because there's tons of them in clippy :D
-            // To my humble reviewer: thoughts?
-            if path.segments.len() >= 4 // A 2 segment path seems okay, like `std::println!`
-                && segments.eq(path.segments.iter().map(|segment| segment.ident.name.as_str()))
-                && !is_from_proc_macro(cx, qpath)
-            {
-                span_lint(
-                    cx,
-                    ABSOLUTE_SYMBOL_PATHS,
-                    span,
-                    "consider referring to this symbol by adding a `use` statement for consistent formatting",
-                );
-            }
+            span_lint(
+                cx,
+                ABSOLUTE_SYMBOL_PATHS,
+                span,
+                "consider referring to this symbol by adding a `use` statement for consistent formatting",
+            );
         }
 
         walk_qpath(self, qpath, hir_id);

clippy_lints/src/lib.rs

@@ -1079,6 +1079,14 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(|_| Box::new(manual_range_patterns::ManualRangePatterns));
     store.register_early_pass(|| Box::new(visibility::Visibility));
     store.register_late_pass(move |_| Box::new(tuple_array_conversions::TupleArrayConversions { msrv: msrv() }));
+    let absolute_symbol_paths_max_segments = conf.absolute_symbol_paths_max_segments;
+    let absolute_symbol_paths_allow_std = conf.absolute_symbol_paths_allow_std;
+    store.register_late_pass(move |_| {
+        Box::new(absolute_symbol_paths::AbsoluteSymbolPaths {
+            absolute_symbol_paths_max_segments,
+            absolute_symbol_paths_allow_std,
+        })
+    });
     // add lints here, do not remove this comment, it's used in `new_lint`
 }
 

clippy_lints/src/utils/conf.rs

@@ -551,6 +551,14 @@ define_Conf! {
     ///
     /// Whether to allow `r#""#` when `r""` can be used
     (allow_one_hash_in_raw_strings: bool = false),
+    /// Lint: ABSOLUTE_SYMBOL_PATHS.
+    ///
+    /// The max number of segments a path can have before being linted
+    (absolute_symbol_paths_max_segments: u64 = 3),
+    /// Lint: ABSOLUTE_SYMBOL_PATHS.
+    ///
+    /// Whether to allow paths originating from `core`/`std`/`alloc`
+    (absolute_symbol_paths_allow_std: bool = false),
 }
 
 /// Search for the configuration file.

clippy_utils/src/usage.rs

@@ -1,6 +1,7 @@
 use crate as utils;
 use crate::visitors::{for_each_expr, for_each_expr_with_closures, Descend};
 use core::ops::ControlFlow;
+use hir::def::Res;
 use rustc_hir as hir;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::HirIdSet;
@@ -129,7 +130,7 @@ impl<'a, 'tcx> intravisit::Visitor<'tcx> for BindingUsageFinder<'a, 'tcx> {
     }
 
     fn visit_path(&mut self, path: &hir::Path<'tcx>, _: hir::HirId) {
-        if let hir::def::Res::Local(id) = path.res {
+        if let Res::Local(id) = path.res {
             if self.binding_ids.contains(&id) {
                 self.usage_found = true;
             }

tests/ui-toml/absolute_symbol_paths/absolute_symbol_paths.allow_std.stderr

@@ -0,0 +1,34 @@
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:40:5
+   |
+LL |     a::b::c::C;
+   |     ^^^^^^^^^^
+   |
+   = note: `-D clippy::absolute-symbol-paths` implied by `-D warnings`
+
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:41:5
+   |
+LL |     a::b::c::d::e::f::F;
+   |     ^^^^^^^^^^^^^^^^^^^
+
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:43:5
+   |
+LL |     a::b::B;
+   |     ^^^^^^^
+
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:44:5
+   |
+LL |     a::b::c::C::ZERO;
+   |     ^^^^^^^^^^
+
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:45:15
+   |
+LL |     fn b() -> a::b::B {
+   |               ^^^^^^^
+
+error: aborting due to 5 previous errors
+

tests/ui-toml/absolute_symbol_paths/absolute_symbol_paths.disallow_std.stderr

@@ -0,0 +1,46 @@
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:38:5
+   |
+LL |     std::f32::MAX;
+   |     ^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::absolute-symbol-paths` implied by `-D warnings`
+
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:39:5
+   |
+LL |     core::f32::MAX;
+   |     ^^^^^^^^^^^^^^
+
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:40:5
+   |
+LL |     a::b::c::C;
+   |     ^^^^^^^^^^
+
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:41:5
+   |
+LL |     a::b::c::d::e::f::F;
+   |     ^^^^^^^^^^^^^^^^^^^
+
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:43:5
+   |
+LL |     a::b::B;
+   |     ^^^^^^^
+
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:44:5
+   |
+LL |     a::b::c::C::ZERO;
+   |     ^^^^^^^^^^
+
+error: consider referring to this symbol by adding a `use` statement for consistent formatting
+  --> $DIR/absolute_symbol_paths.rs:45:15
+   |
+LL |     fn b() -> a::b::B {
+   |               ^^^^^^^
+
+error: aborting due to 7 previous errors
+

tests/ui/absolute_symbol_paths.rs renamed to tests/ui-toml/absolute_symbol_paths/absolute_symbol_paths.rs

@@ -1,4 +1,7 @@
 //@aux-build:proc_macros.rs:proc-macro
+//@revisions: allow_std disallow_std
+//@[allow_std] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/absolute_symbol_paths/allow_std
+//@[disallow_std] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/absolute_symbol_paths/disallow_std
 #![allow(clippy::no_effect, unused)]
 #![warn(clippy::absolute_symbol_paths)]
 #![feature(decl_macro)]
@@ -14,6 +17,14 @@ pub mod a {
             impl C {
                 pub const ZERO: u32 = 0;
             }
+
+            pub mod d {
+                pub mod e {
+                    pub mod f {
+                        pub struct F;
+                    }
+                }
+            }
         }
 
         pub struct B;
@@ -27,6 +38,7 @@ fn main() {
     std::f32::MAX;
     core::f32::MAX;
     a::b::c::C;
+    a::b::c::d::e::f::F;
     a::A;
     a::b::B;
     a::b::c::C::ZERO;

tests/ui-toml/absolute_symbol_paths/allow_std/clippy.toml

@@ -0,0 +1,2 @@
+absolute-symbol-paths-max-segments = 2
+absolute-symbol-paths-allow-std = true