refactor(noUnusedImports): keep orphan comments (#4479)

Author: Conaclos

CHANGELOG.md

@@ -155,6 +155,19 @@ our [guidelines for writing a good changelog entry](https://github.com/biomejs/b
 
   Contributed by @Conaclos
 
+- `noUnusedImports` now keeps comments separated from the import with a blank line ([#3401](https://github.com/biomejs/biome/issues/3401)).
+
+  Here is an example:
+
+  ```diff
+    // Orphan comment
+
+  - // Header comment
+  - import {} from "mod";
+  ```
+
+  Contributed by @Conaclos
+
 #### Bug fixes
 
 - [useArrayLiterals](https://biomejs.dev/linter/rules/use-array-literals/) now reports all expressions using the `Array` constructors.

crates/biome_js_analyze/src/lint/correctness/no_unused_imports.rs

@@ -216,6 +216,32 @@ impl Rule for NoUnusedImports {
         match state {
             Unused::EmptyStatement(_) | Unused::AllImports(_) => {
                 let parent = node.syntax().parent()?;
+                let leading_trivia = parent.first_leading_trivia()?;
+                let mut leading_trivia_pieces = leading_trivia.pieces().collect::<Vec<_>>();
+                let blank_line_pos = leading_trivia_pieces
+                    .windows(2)
+                    .rposition(|window| window[0].is_newline() && window[1].is_newline());
+                if let Some(blank_line_pos) = blank_line_pos {
+                    // keep all leading trivia until the last blank line.
+                    leading_trivia_pieces.truncate(blank_line_pos + 1);
+                    if let Some(prev_sibling) = parent.prev_sibling() {
+                        let new_prev_sibling = prev_sibling
+                            .clone()
+                            .append_trivia_pieces(leading_trivia_pieces)?;
+                        mutation.replace_element_discard_trivia(
+                            prev_sibling.into(),
+                            new_prev_sibling.into(),
+                        );
+                    } else if let Some(next_sibling) = parent.next_sibling() {
+                        let new_next_sibling = next_sibling
+                            .clone()
+                            .prepend_trivia_pieces(leading_trivia_pieces)?;
+                        mutation.replace_element_discard_trivia(
+                            next_sibling.into(),
+                            new_next_sibling.into(),
+                        );
+                    }
+                }
                 mutation.remove_element(parent.into());
             }
             Unused::DefaultImport(_) => {

crates/biome_js_analyze/tests/specs/correctness/noUnusedImports/invalid-import-namespace.ts.snap

@@ -48,10 +48,11 @@ invalid-import-namespace.ts:4:18 lint/correctness/noUnusedImports  FIXABLE  ━
   i Safe fix: Remove the unused imports.
   
     1 1 │   import * as Ns1 from ""
-    2 2 │   export type T1 = Ns1;
-    3   │ - 
+    2   │ - export·type·T1·=·Ns1;
+      2 │ + export·type·T1·=·Ns1;
+    3 3 │   
     4   │ - import·type·*·as·Ns2·from·""
-    5 3 │   export type T2 = Ns2;
+    5 4 │   export type T2 = Ns2;
   
 
 ```

crates/biome_js_analyze/tests/specs/correctness/noUnusedImports/invalid-unused-react.jsx.snap

@@ -100,12 +100,14 @@ invalid-unused-react.jsx:5:8 lint/correctness/noUnusedImports  FIXABLE  ━━
   
   i Safe fix: Remove the unused imports.
   
+    1 1 │   import X from "react"
     2 2 │   import * as X from "react"
-    3 3 │   import { default as X } from "react"
-    4   │ - 
+    3   │ - import·{·default·as·X·}·from·"react"
+      3 │ + import·{·default·as·X·}·from·"react"
+    4 4 │   
     5   │ - import·React·from·"x"
-    6 4 │   import * as React from "x"
-    7 5 │   import { default as React } from "x"
+    6 5 │   import * as React from "x"
+    7 6 │   import { default as React } from "x"
   
 
 ```

crates/biome_js_analyze/tests/specs/correctness/noUnusedImports/invalid.js.snap

@@ -81,12 +81,13 @@ invalid.js:5:13 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━
   i Safe fix: Remove the unused imports.
   
      1  1 │   // Header comment
-     2  2 │   import A from "mod";
-     3    │ - 
+     2    │ - import·A·from·"mod";
+        2 │ + import·A·from·"mod";
+     3  3 │   
      4    │ - //·Header·comment
      5    │ - import·*·as·B·from·"mod";·//·Import·comment
-     6  3 │   
-     7  4 │   // Header comment
+     6  4 │   
+     7  5 │   // Header comment
   
 
 ```
@@ -106,13 +107,15 @@ invalid.js:8:8 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━
   
   i Safe fix: Remove the unused imports.
   
+     3  3 │   
      4  4 │   // Header comment
-     5  5 │   import * as B from "mod"; // Import comment
-     6    │ - 
+     5    │ - import·*·as·B·from·"mod";·//·Import·comment
+        5 │ + import·*·as·B·from·"mod";·//·Import·comment
+     6  6 │   
      7    │ - //·Header·comment
      8    │ - import·{·C·}·from·"mod";·//·Import·comment
-     9  6 │   
-    10  7 │   // Header comment
+     9  7 │   
+    10  8 │   // Header comment
   
 
 ```
@@ -132,13 +135,15 @@ invalid.js:11:14 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━
   
   i Safe fix: Remove the unused imports.
   
+     6  6 │   
      7  7 │   // Header comment
-     8  8 │   import { C } from "mod"; // Import comment
-     9    │ - 
+     8    │ - import·{·C·}·from·"mod";·//·Import·comment
+        8 │ + import·{·C·}·from·"mod";·//·Import·comment
+     9  9 │   
     10    │ - //·Header·comment
     11    │ - import·/*a*/·D·/*b*/,·/*c*/{·E·}/*d*/·from·"mod";·//·Import·comment
-    12  9 │   
-    13 10 │   import /*a*/ F /*b*/, /*c*/ * as G /*d*/ from "mod";
+    12 10 │   
+    13 11 │   import /*a*/ F /*b*/, /*c*/ * as G /*d*/ from "mod";
   
 
 ```
@@ -159,12 +164,14 @@ invalid.js:13:14 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━
   
   i Safe fix: Remove the unused imports.
   
+     9  9 │   
     10 10 │   // Header comment
-    11 11 │   import /*a*/ D /*b*/, /*c*/{ E }/*d*/ from "mod"; // Import comment
-    12    │ - 
+    11    │ - import·/*a*/·D·/*b*/,·/*c*/{·E·}/*d*/·from·"mod";·//·Import·comment
+       11 │ + import·/*a*/·D·/*b*/,·/*c*/{·E·}/*d*/·from·"mod";·//·Import·comment
+    12 12 │   
     13    │ - import·/*a*/·F·/*b*/,·/*c*/·*·as·G·/*d*/·from·"mod";
-    14 12 │   
-    15 13 │   import {
+    14 13 │   
+    15 14 │   import {
   
 
 ```
@@ -190,16 +197,18 @@ invalid.js:15:8 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━
   
   i Safe fix: Remove the unused imports.
   
+    11 11 │   import /*a*/ D /*b*/, /*c*/{ E }/*d*/ from "mod"; // Import comment
     12 12 │   
-    13 13 │   import /*a*/ F /*b*/, /*c*/ * as G /*d*/ from "mod";
-    14    │ - 
+    13    │ - import·/*a*/·F·/*b*/,·/*c*/·*·as·G·/*d*/·from·"mod";
+       13 │ + import·/*a*/·F·/*b*/,·/*c*/·*·as·G·/*d*/·from·"mod";
+    14 14 │   
     15    │ - import·{
     16    │ - ····//·Comment
     17    │ - ····H,
     18    │ - ····I,
     19    │ - }·from·"mod";
-    20 14 │   
-    21 15 │   import {/*a*/J/*b*/, /*c*/K/*d*/} from "mod";
+    20 15 │   
+    21 16 │   import {/*a*/J/*b*/, /*c*/K/*d*/} from "mod";
   
 
 ```
@@ -220,12 +229,14 @@ invalid.js:21:8 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━
   
   i Safe fix: Remove the unused imports.
   
+    17 17 │       H,
     18 18 │       I,
-    19 19 │   } from "mod";
-    20    │ - 
+    19    │ - }·from·"mod";
+       19 │ + }·from·"mod";
+    20 20 │   
     21    │ - import·{/*a*/J/*b*/,·/*c*/K/*d*/}·from·"mod";
-    22 20 │   
-    23 21 │   // Header comment
+    22 21 │   
+    23 22 │   // Header comment
   
 
 ```
@@ -245,13 +256,15 @@ invalid.js:24:8 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━
   
   i Safe fix: Remove the unused imports.
   
+    19 19 │   } from "mod";
     20 20 │   
-    21 21 │   import {/*a*/J/*b*/, /*c*/K/*d*/} from "mod";
-    22    │ - 
+    21    │ - import·{/*a*/J/*b*/,·/*c*/K/*d*/}·from·"mod";
+       21 │ + import·{/*a*/J/*b*/,·/*c*/K/*d*/}·from·"mod";
+    22 22 │   
     23    │ - //·Header·comment
     24    │ - import·{·L·as·M,·}·from·"mod";·//·Import·comment
-    25 22 │   
-    26 23 │   // See https://github.com/biomejs/biome/issues/653
+    25 23 │   
+    26 24 │   // See https://github.com/biomejs/biome/issues/653
   
 
 ```
@@ -296,11 +309,13 @@ invalid.js:32:9 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━
   
   i Safe fix: Remove the unused imports.
   
+    28 28 │   import {d} from 'd'
     29 29 │   import {b} from 'b'
-    30 30 │   export const bb = a + b
-    31    │ - 
+    30    │ - export·const·bb·=·a·+·b
+       30 │ + export·const·bb·=·a·+·b
+    31 31 │   
     32    │ - import·{}·from·"mod"
-    33 31 │   
+    33 32 │   
   
 
 ```

crates/biome_js_analyze/tests/specs/correctness/noUnusedImports/invalid.jsx.snap

@@ -110,12 +110,14 @@ invalid.jsx:5:8 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━━
   
   i Safe fix: Remove the unused imports.
   
+     1  1 │   import X from "react"
      2  2 │   import * as X from "react"
-     3  3 │   import { default as X } from "react"
-     4    │ - 
+     3    │ - import·{·default·as·X·}·from·"react"
+        3 │ + import·{·default·as·X·}·from·"react"
+     4  4 │   
      5    │ - import·React·from·"x"
-     6  4 │   import * as React from "x"
-     7  5 │   import { default as React } from "x"
+     6  5 │   import * as React from "x"
+     7  6 │   import { default as React } from "x"
   
 
 ```
@@ -209,13 +211,15 @@ invalid.jsx:11:8 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━
   
   i Safe fix: Remove the unused imports.
   
+     6  6 │   import * as React from "x"
      7  7 │   import { default as React } from "x"
-     8  8 │   import React, { useEffect } from "x"
-     9    │ - 
+     8    │ - import·React,·{·useEffect·}·from·"x"
+        8 │ + import·React,·{·useEffect·}·from·"x"
+     9  9 │   
     10    │ - //·unsupported·patterns
     11    │ - import·X,·{·default·as·React·}·from·"react"
-    12  9 │   import X, * as React from "react"
-    13 10 │   
+    12 10 │   import X, * as React from "react"
+    13 11 │   
   
 
 ```
@@ -260,13 +264,15 @@ invalid.jsx:15:8 lint/correctness/noUnusedImports  FIXABLE  ━━━━━━
   
   i Safe fix: Remove the unused imports.
   
+    10 10 │   // unsupported patterns
     11 11 │   import X, { default as React } from "react"
-    12 12 │   import X, * as React from "react"
-    13    │ - 
+    12    │ - import·X,·*·as·React·from·"react"
+       12 │ + import·X,·*·as·React·from·"react"
+    13 13 │   
     14    │ - //·React·import·(no·exception)
     15    │ - import·React·from·"react"
-    16 13 │   import * as React from "react"
-    17 14 │   import { default as React } from "react"
+    16 14 │   import * as React from "react"
+    17 15 │   import { default as React } from "react"
   
 
 ```

crates/biome_js_analyze/tests/specs/correctness/noUnusedImports/invalid.ts

@@ -7,6 +7,8 @@ import type * as B from "mod"; // Import comment
 // Header comment
 import type { C } from "mod"; // Import comment
 
+// Orphan comment
+
 // Header comment
 import /*a*/ D /*b*/, /*c*/{ type E }/*d*/ from "mod"; // Import comment
 
@@ -22,3 +24,4 @@ import {/*a*/type J/*b*/, /*c*/type K/*d*/} from "mod";
 
 // Header comment
 import type { L as M, } from "mod"; // Import comment
+