add configuration for [wildcard_imports] to ignore certain imports

Author: J-ZhengLi

clippy_config/src/conf.rs

@@ -552,6 +552,11 @@ define_Conf! {
     /// Lint "public" fields in a struct that are prefixed with an underscore based on their
     /// exported visibility, or whether they are marked as "pub".
     (pub_underscore_fields_behavior: PubUnderscoreFieldsBehaviour = PubUnderscoreFieldsBehaviour::PublicallyExported),
+    /// Lint: WILDCARD_IMPORTS.
+    ///
+    /// List of path segments to ignore when checking wildcard imports,
+    /// could get overrided by `warn_on_all_wildcard_imports`.
+    (ignored_wildcard_imports: Vec<String> = Vec::new()),
 }
 
 /// Search for the configuration file.

clippy_lints/src/lib.rs

@@ -542,6 +542,7 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
         excessive_nesting_threshold,
         future_size_threshold,
         ref ignore_interior_mutability,
+        ref ignored_wildcard_imports,
         large_error_threshold,
         literal_representation_threshold,
         matches_for_let_else,
@@ -871,7 +872,12 @@ 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,
+            ignored_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,
+    ignored_segments: Vec<String>,
 }
 
 impl WildcardImports {
-    pub fn new(warn_on_all: bool) -> Self {
+    pub fn new(warn_on_all: bool, ignored_wildcard_imports: Vec<String>) -> Self {
         Self {
             warn_on_all,
             test_modules_deep: 0,
+            ignored_segments: ignored_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_ignored_via_config(segments, &self.ignored_segments)
     }
 }
 
@@ -198,10 +202,20 @@ 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 `ignored-wildcard-imports = ["utils"]` in `Clippy.toml`
+fn is_ignored_via_config(segments: &[PathSegment<'_>], ignored_segments: &[String]) -> bool {
+    let segments_set: FxHashSet<&str> = segments.iter().map(|s| s.ident.as_str()).collect();
+    let ignored_set: FxHashSet<&str> = ignored_segments.iter().map(String::as_str).collect();
+    // 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_set.intersection(&ignored_set).next().is_some()
+}

tests/ui-toml/toml_unknown_key/conf_unknown_key.stderr

@@ -37,6 +37,7 @@ error: error reading Clippy's configuration file: unknown field `foobar`, expect
            excessive-nesting-threshold
            future-size-threshold
            ignore-interior-mutability
+           ignored-wildcard-imports
            large-error-threshold
            literal-representation-threshold
            matches-for-let-else
@@ -113,6 +114,7 @@ error: error reading Clippy's configuration file: unknown field `barfoo`, expect
            excessive-nesting-threshold
            future-size-threshold
            ignore-interior-mutability
+           ignored-wildcard-imports
            large-error-threshold
            literal-representation-threshold
            matches-for-let-else

tests/ui-toml/wildcard_imports_whitelist/clippy.toml

@@ -0,0 +1 @@
+ignored-wildcard-imports = ["utils"]

tests/ui-toml/wildcard_imports_whitelist/wildcard_imports.fixed

@@ -0,0 +1,18 @@
+#![warn(clippy::wildcard_imports)]
+
+mod utils {
+    pub fn print() {}
+}
+
+mod utils_plus {
+    pub fn do_something() {}
+}
+
+use utils::*;
+use utils_plus::do_something;
+//~^ ERROR: usage of wildcard import
+
+fn main() {
+    print();
+    do_something();
+}

tests/ui-toml/wildcard_imports_whitelist/wildcard_imports.rs

@@ -0,0 +1,18 @@
+#![warn(clippy::wildcard_imports)]
+
+mod utils {
+    pub fn print() {}
+}
+
+mod utils_plus {
+    pub fn do_something() {}
+}
+
+use utils::*;
+use utils_plus::*;
+//~^ ERROR: usage of wildcard import
+
+fn main() {
+    print();
+    do_something();
+}

tests/ui-toml/wildcard_imports_whitelist/wildcard_imports.stderr

@@ -0,0 +1,11 @@
+error: usage of wildcard import
+  --> $DIR/wildcard_imports.rs:12:5
+   |
+LL | use utils_plus::*;
+   |     ^^^^^^^^^^^^^ help: try: `utils_plus::do_something`
+   |
+   = 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
+