feat(linter/import): improve multiple exports error message (#3160)

https://github.com/oxc-project/oxc/issues/3157#issuecomment-2094113518

crates/oxc_linter/src/rules/import/export.rs

@@ -1,8 +1,9 @@
 use std::path::PathBuf;
 
 use oxc_diagnostics::{
-    miette::{self, Diagnostic},
+    miette::{self, miette, Diagnostic, LabeledSpan},
     thiserror::{self, Error},
+    Severity,
 };
 use oxc_macros::declare_oxc_lint;
 use oxc_semantic::ModuleRecord;
@@ -13,9 +14,6 @@ use crate::{context::LintContext, rule::Rule};
 
 #[derive(Debug, Error, Diagnostic)]
 enum ExportDiagnostic {
-    #[error("eslint-plugin-import(export): Multiple exports of name '{1}'.")]
-    #[diagnostic(severity(warning))]
-    MultipleNamedExport(#[label] Span, CompactStr),
     #[error("eslint-plugin-import(export): No named exports found in module '{1}'")]
     #[diagnostic(severity(warning))]
     NoNamedExport(#[label] Span, CompactStr),
@@ -43,55 +41,79 @@ impl Rule for Export {
     fn run_once(&self, ctx: &LintContext<'_>) {
         let module_record = ctx.semantic().module_record();
         let named_export = &module_record.exported_bindings;
-        let mut duplicated_named_export = FxHashMap::default();
+
-        for export_entry in &module_record.star_export_entries {
+        let mut all_export_names = FxHashMap::default();
-            let Some(module_request) = &export_entry.module_request else {
+        let mut visited = FxHashSet::default();
-                continue;
+
-            };
+        module_record.star_export_entries.iter().for_each(|star_export_entry| {
+            let mut export_names = FxHashSet::default();
+
+            let Some(module_request) = &star_export_entry.module_request else { return };
             let Some(remote_module_record_ref) =
                 module_record.loaded_modules.get(module_request.name())
             else {
-                continue;
+                return;
             };
 
-            let remote_module_record = remote_module_record_ref.value();
+            walk_exported_recursive(
-            let mut all_export_names = FxHashSet::default();
+                remote_module_record_ref.value(),
-            let mut visited = FxHashSet::default();
+                &mut export_names,
-            walk_exported_recursive(remote_module_record, &mut all_export_names, &mut visited);
+                &mut visited,
-            if all_export_names.is_empty() {
+            );
+
+            if export_names.is_empty() {
                 ctx.diagnostic(ExportDiagnostic::NoNamedExport(
                     module_request.span(),
                     module_request.name().clone(),
                 ));
-                continue;
+            } else {
+                all_export_names.insert(star_export_entry.span, export_names);
             }
+        });
 
-            for name in &all_export_names {
+        for (name, span) in named_export {
-                if let Some(span) = named_export.get(name) {
+            let mut spans = all_export_names
-                    duplicated_named_export.entry(*span).or_insert_with(|| name.clone());
+                .iter()
-                }
+                .filter_map(|(star_export_entry_span, export_names)| {
-            }
+                    if export_names.contains(name) {
-        }
+                        Some(*star_export_entry_span)
-
+                    } else {
-        for (span, name) in duplicated_named_export {
+                        None
-            ctx.diagnostic(ExportDiagnostic::MultipleNamedExport(span, name));
                     }
+                })
+                .collect::<Vec<_>>();
 
             for name_span in &module_record.exported_bindings_duplicated {
-            let name = name_span.name().clone();
+                if name == name_span.name() {
-            if let Some(span) = module_record.exported_bindings.get(&name) {
+                    spans.push(name_span.span());
-                ctx.diagnostic(ExportDiagnostic::MultipleNamedExport(*span, name.clone()));
                 }
-            ctx.diagnostic(ExportDiagnostic::MultipleNamedExport(name_span.span(), name));
             }
+
+            if !spans.is_empty() {
+                spans.push(*span);
+                let labels = spans.into_iter().map(LabeledSpan::underline).collect::<Vec<_>>();
+
+                ctx.diagnostic(miette!(
+                    severity = Severity::Warning,
+                    labels = labels,
+                    "eslint-plugin-import(export): Multiple exports of name '{name}'."
+                ));
+            }
+        }
+
         if !module_record.export_default_duplicated.is_empty() {
+            let mut spans = module_record.export_default_duplicated.clone();
             if let Some(span) = module_record.export_default {
-                ctx.diagnostic(ExportDiagnostic::MultipleNamedExport(span, "default".into()));
+                spans.push(span);
+                let labels = spans.into_iter().map(LabeledSpan::underline).collect::<Vec<_>>();
+
+                ctx.diagnostic(miette!(
+                    severity = Severity::Warning,
+                    labels = labels,
+                    "eslint-plugin-import(export): Multiple default exports."
+                ));
             }
         }
-        for span in &module_record.export_default_duplicated {
-            ctx.diagnostic(ExportDiagnostic::MultipleNamedExport(*span, "default".into()));
-        }
     }
 }
 

crates/oxc_linter/src/snapshots/export.snap

@@ -5,13 +5,13 @@ expression: export
   ⚠ eslint-plugin-import(export): Multiple exports of name 'foo'.
    ╭─[index.ts:1:19]
  1 │ let foo; export { foo }; export * from "./export-all"
-   ·                   ───
+   ·                   ───    ────────────────────────────
    ╰────
 
   ⚠ eslint-plugin-import(export): Multiple exports of name 'foo'.
    ╭─[index.ts:1:26]
  1 │ let foo; export { foo as "foo" }; export * from "./export-all"
-   ·                          ─────
+   ·                          ─────    ────────────────────────────
    ╰────
 
   × Identifier `Foo` has already been declared
@@ -98,18 +98,13 @@ expression: export
  4 │                 export namespace Foo { }
    ╰────
 
-  ⚠ eslint-plugin-import(export): Multiple exports of name 'default'.
-    ╭─[index.ts:9:32]
-  8 │                 const Baz = 3;
-  9 │                 export {Baz as default};
-    ·                                ───────
- 10 │             
-    ╰────
-
   ⚠ eslint-plugin-import(export): Multiple exports of name 'default'.
     ╭─[index.ts:7:32]
   6 │                 const Bar = 2;
   7 │                 export {Bar as default};
     ·                                ───────
   8 │                 const Baz = 3;
+  9 │                 export {Baz as default};
+    ·                                ───────
+ 10 │             
     ╰────