Auto merge of rust-lang#11979 - J-ZhengLi:issue11428, r=Alexendoo

add configuration for [`wildcard_imports`] to ignore certain imports

fixes: rust-lang#11428

changelog: add configuration `ignored-wildcard-imports` for lint [`wildcard_imports`]

Author: bors

CHANGELOG.md

@@ -5824,4 +5824,5 @@ Released 2018-09-13
 [`check-private-items`]: https://doc.rust-lang.org/clippy/lint_configuration.html#check-private-items
 [`pub-underscore-fields-behavior`]: https://doc.rust-lang.org/clippy/lint_configuration.html#pub-underscore-fields-behavior
 [`allow-comparison-to-zero`]: https://doc.rust-lang.org/clippy/lint_configuration.html#allow-comparison-to-zero
+[`allowed-wildcard-imports`]: https://doc.rust-lang.org/clippy/lint_configuration.html#allowed-wildcard-imports
 <!-- end autogenerated links to configuration documentation -->

book/src/lint_configuration.md

@@ -838,3 +838,25 @@ Don't lint when comparing the result of a modulo operation to zero.
 * [`modulo_arithmetic`](https://rust-lang.github.io/rust-clippy/master/index.html#modulo_arithmetic)
 
 
+## `allowed-wildcard-imports`
+List of path segments allowed to have wildcard imports.
+
+#### Example
+
+```toml
+allowed-wildcard-imports = [ "utils", "common" ]
+```
+
+#### Noteworthy
+
+1. This configuration has no effects if used with `warn_on_all_wildcard_imports = true`.
+2. Paths with any segment that containing the word 'prelude'
+are already allowed by default.
+
+**Default Value:** `[]`
+
+---
+**Affected lints:**
+* [`wildcard_imports`](https://rust-lang.github.io/rust-clippy/master/index.html#wildcard_imports)
+
+

clippy_config/src/conf.rs

@@ -571,6 +571,22 @@ define_Conf! {
     ///
     /// Don't lint when comparing the result of a modulo operation to zero.
     (allow_comparison_to_zero: bool = true),
+    /// Lint: WILDCARD_IMPORTS.
+    ///
+    /// List of path segments allowed to have wildcard imports.
+    ///
+    /// #### Example
+    ///
+    /// ```toml
+    /// allowed-wildcard-imports = [ "utils", "common" ]
+    /// ```
+    ///
+    /// #### Noteworthy
+    ///
+    /// 1. This configuration has no effects if used with `warn_on_all_wildcard_imports = true`.
+    /// 2. Paths with any segment that containing the word 'prelude'
+    /// are already allowed by default.
+    (allowed_wildcard_imports: FxHashSet<String> = FxHashSet::default()),
 }
 
 /// Search for the configuration file.

clippy_lints/src/lib.rs

@@ -524,6 +524,7 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
         ref allowed_dotfiles,
         ref allowed_idents_below_min_chars,
         ref allowed_scripts,
+        ref allowed_wildcard_imports,
         ref arithmetic_side_effects_allowed_binary,
         ref arithmetic_side_effects_allowed_unary,
         ref arithmetic_side_effects_allowed,
@@ -876,7 +877,12 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
         ))
     });
     store.register_early_pass(|| Box::new(option_env_unwrap::OptionEnvUnwrap));
-    store.register_late_pass(move |_| Box::new(wildcard_imports::WildcardImports::new(warn_on_all_wildcard_imports)));
+    store.register_late_pass(move |_| {
+        Box::new(wildcard_imports::WildcardImports::new(
+            warn_on_all_wildcard_imports,
+            allowed_wildcard_imports.clone(),
+        ))
+    });
     store.register_late_pass(|_| Box::<redundant_pub_crate::RedundantPubCrate>::default());
     store.register_late_pass(|_| Box::new(unnamed_address::UnnamedAddress));
     store.register_late_pass(|_| Box::<dereference::Dereferencing<'_>>::default());

clippy_lints/src/wildcard_imports.rs

@@ -1,6 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::is_test_module_or_function;
 use clippy_utils::source::{snippet, snippet_with_applicability};
+use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::Applicability;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{Item, ItemKind, PathSegment, UseKind};
@@ -100,13 +101,15 @@ declare_clippy_lint! {
 pub struct WildcardImports {
     warn_on_all: bool,
     test_modules_deep: u32,
+    allowed_segments: FxHashSet<String>,
 }
 
 impl WildcardImports {
-    pub fn new(warn_on_all: bool) -> Self {
+    pub fn new(warn_on_all: bool, allowed_wildcard_imports: FxHashSet<String>) -> Self {
         Self {
             warn_on_all,
             test_modules_deep: 0,
+            allowed_segments: allowed_wildcard_imports,
         }
     }
 }
@@ -190,6 +193,7 @@ impl WildcardImports {
         item.span.from_expansion()
             || is_prelude_import(segments)
             || (is_super_only_import(segments) && self.test_modules_deep > 0)
+            || is_allowed_via_config(segments, &self.allowed_segments)
     }
 }
 
@@ -198,10 +202,18 @@ impl WildcardImports {
 fn is_prelude_import(segments: &[PathSegment<'_>]) -> bool {
     segments
         .iter()
-        .any(|ps| ps.ident.name.as_str().contains(sym::prelude.as_str()))
+        .any(|ps| ps.ident.as_str().contains(sym::prelude.as_str()))
 }
 
 // Allow "super::*" imports in tests.
 fn is_super_only_import(segments: &[PathSegment<'_>]) -> bool {
     segments.len() == 1 && segments[0].ident.name == kw::Super
 }
+
+// Allow skipping imports containing user configured segments,
+// i.e. "...::utils::...::*" if user put `allowed-wildcard-imports = ["utils"]` in `Clippy.toml`
+fn is_allowed_via_config(segments: &[PathSegment<'_>], allowed_segments: &FxHashSet<String>) -> bool {
+    // segment matching need to be exact instead of using 'contains', in case user unintentionaly put
+    // a single character in the config thus skipping most of the warnings.
+    segments.iter().any(|seg| allowed_segments.contains(seg.ident.as_str()))
+}

tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr

@@ -15,6 +15,7 @@ error: error reading Clippy's configuration file: unknown field `foobar`, expect
            allowed-duplicate-crates
            allowed-idents-below-min-chars
            allowed-scripts
+           allowed-wildcard-imports
            arithmetic-side-effects-allowed
            arithmetic-side-effects-allowed-binary
            arithmetic-side-effects-allowed-unary
@@ -93,6 +94,7 @@ error: error reading Clippy's configuration file: unknown field `barfoo`, expect
            allowed-duplicate-crates
            allowed-idents-below-min-chars
            allowed-scripts
+           allowed-wildcard-imports
            arithmetic-side-effects-allowed
            arithmetic-side-effects-allowed-binary
            arithmetic-side-effects-allowed-unary
@@ -171,6 +173,7 @@ error: error reading Clippy's configuration file: unknown field `allow_mixed_uni
            allowed-duplicate-crates
            allowed-idents-below-min-chars
            allowed-scripts
+           allowed-wildcard-imports
            arithmetic-side-effects-allowed
            arithmetic-side-effects-allowed-binary
            arithmetic-side-effects-allowed-unary

tests/ui-toml/wildcard_imports/clippy.toml

@@ -1 +1,4 @@
 warn-on-all-wildcard-imports = true
+
+# This should be ignored since `warn-on-all-wildcard-imports` has higher precedence
+allowed-wildcard-imports = ["utils"]

tests/ui-toml/wildcard_imports/wildcard_imports.fixed

@@ -3,9 +3,28 @@
 mod prelude {
     pub const FOO: u8 = 1;
 }
+
+mod utils {
+    pub const BAR: u8 = 1;
+    pub fn print() {}
+}
+
+mod my_crate {
+    pub mod utils {
+        pub fn my_util_fn() {}
+    }
+}
+
+use utils::{BAR, print};
+//~^ ERROR: usage of wildcard import
+use my_crate::utils::my_util_fn;
+//~^ ERROR: usage of wildcard import
 use prelude::FOO;
 //~^ ERROR: usage of wildcard import
 
 fn main() {
     let _ = FOO;
+    let _ = BAR;
+    print();
+    my_util_fn();
 }

tests/ui-toml/wildcard_imports/wildcard_imports.rs

@@ -3,9 +3,28 @@
 mod prelude {
     pub const FOO: u8 = 1;
 }
+
+mod utils {
+    pub const BAR: u8 = 1;
+    pub fn print() {}
+}
+
+mod my_crate {
+    pub mod utils {
+        pub fn my_util_fn() {}
+    }
+}
+
+use utils::*;
+//~^ ERROR: usage of wildcard import
+use my_crate::utils::*;
+//~^ ERROR: usage of wildcard import
 use prelude::*;
 //~^ ERROR: usage of wildcard import
 
 fn main() {
     let _ = FOO;
+    let _ = BAR;
+    print();
+    my_util_fn();
 }

tests/ui-toml/wildcard_imports/wildcard_imports.stderr

@@ -1,11 +1,23 @@
 error: usage of wildcard import
-  --> $DIR/wildcard_imports.rs:6:5
+  --> $DIR/wildcard_imports.rs:18:5
    |
-LL | use prelude::*;
-   |     ^^^^^^^^^^ help: try: `prelude::FOO`
+LL | use utils::*;
+   |     ^^^^^^^^ help: try: `utils::{BAR, print}`
    |
    = note: `-D clippy::wildcard-imports` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::wildcard_imports)]`
 
-error: aborting due to 1 previous error
+error: usage of wildcard import
+  --> $DIR/wildcard_imports.rs:20:5
+   |
+LL | use my_crate::utils::*;
+   |     ^^^^^^^^^^^^^^^^^^ help: try: `my_crate::utils::my_util_fn`
+
+error: usage of wildcard import
+  --> $DIR/wildcard_imports.rs:22:5
+   |
+LL | use prelude::*;
+   |     ^^^^^^^^^^ help: try: `prelude::FOO`
+
+error: aborting due to 3 previous errors