[ruff] Fix panic in unused # noqa removal with multi-byte space (…

…`RUF100`) (#10682)

## Summary

Currently, [this
line](https://github.com/astral-sh/ruff/blob/716688d44ecda5d4648b7a31556bb77afe6cbbc6/crates/ruff_linter/src/fix/edits.rs#L101)
assumes that the `noqa` comment begins with an octothorpe followed by a
space. (`# `) With anyone's random code, this of course is not always
true.

When there's a multi-byte character after the leading octothorpe, such
as
[`\u0085`](https://www.fileformat.info/info/unicode/char/85/index.htm),
we try slicing from within the character, causing a panic.

To fix this, the logic has been changed to remove unused `noqa`
directives and keep any trailing comments, or removing the whole comment
if the comment is just the unused `noqa`

Fixes #10097.

## Test Plan

`cargo test`

crates/ruff_linter/resources/test/fixtures/ruff/RUF100_0.py

@@ -100,3 +100,9 @@ def f():
 
     Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
     """  # noqa
+
+
+def f():
+    # Invalid - nonexistant error code with multibyte character
+    d = 1  #…noqa: F841, E50
+    e = 1  #…noqa: E50

crates/ruff_linter/src/fix/edits.rs

@@ -83,6 +83,7 @@ pub(crate) fn delete_comment(range: TextRange, locator: &Locator) -> Edit {
     }
     // Ex) `x = 1  # noqa`
     else if range.end() + trailing_space_len == line_range.end() {
+        // Replace `x = 1  # noqa` with `x = 1`.
         Edit::deletion(range.start() - leading_space_len, line_range.end())
     }
     // Ex) `x = 1  # noqa  # type: ignore`
@@ -93,13 +94,15 @@ pub(crate) fn delete_comment(range: TextRange, locator: &Locator) -> Edit {
         ))
         .starts_with('#')
     {
+        // Replace `# noqa  # type: ignore` with `# type: ignore`.
         Edit::deletion(range.start(), range.end() + trailing_space_len)
     }
     // Ex) `x = 1  # noqa here`
     else {
-        Edit::deletion(
-            range.start() + "# ".text_len(),
-            range.end() + trailing_space_len,
+        // Replace `# noqa here` with `# here`.
+        Edit::range_replacement(
+            "# ".to_string(),
+            TextRange::new(range.start(), range.end() + trailing_space_len),
         )
     }
 }

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__ruf100_0.snap

@@ -284,4 +284,51 @@ RUF100_0.py:93:92: RUF100 [*] Unused `noqa` directive (unused: `F401`)
 95 95 | 
 96 96 | def f():
 
+RUF100_0.py:107:12: RUF100 [*] Unused `noqa` directive (unknown: `E50`)
+    |
+105 | def f():
+106 |     # Invalid - nonexistant error code with multibyte character
+107 |     d = 1  #…noqa: F841, E50
+    |            ^^^^^^^^^^^^^^^^ RUF100
+108 |     e = 1  #…noqa: E50
+    |
+    = help: Remove unused `noqa` directive
 
+ℹ Safe fix
+104 104 | 
+105 105 | def f():
+106 106 |     # Invalid - nonexistant error code with multibyte character
+107     |-    d = 1  #…noqa: F841, E50
+    107 |+    d = 1  # noqa: F841
+108 108 |     e = 1  #…noqa: E50
+
+RUF100_0.py:108:5: F841 [*] Local variable `e` is assigned to but never used
+    |
+106 |     # Invalid - nonexistant error code with multibyte character
+107 |     d = 1  #…noqa: F841, E50
+108 |     e = 1  #…noqa: E50
+    |     ^ F841
+    |
+    = help: Remove assignment to unused variable `e`
+
+ℹ Unsafe fix
+105 105 | def f():
+106 106 |     # Invalid - nonexistant error code with multibyte character
+107 107 |     d = 1  #…noqa: F841, E50
+108     |-    e = 1  #…noqa: E50
+
+RUF100_0.py:108:12: RUF100 [*] Unused `noqa` directive (unknown: `E50`)
+    |
+106 |     # Invalid - nonexistant error code with multibyte character
+107 |     d = 1  #…noqa: F841, E50
+108 |     e = 1  #…noqa: E50
+    |            ^^^^^^^^^^ RUF100
+    |
+    = help: Remove unused `noqa` directive
+
+ℹ Safe fix
+105 105 | def f():
+106 106 |     # Invalid - nonexistant error code with multibyte character
+107 107 |     d = 1  #…noqa: F841, E50
+108     |-    e = 1  #…noqa: E50
+    108 |+    e = 1

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__ruf100_0_prefix.snap

@@ -264,4 +264,51 @@ RUF100_0.py:93:92: RUF100 [*] Unused `noqa` directive (unused: `F401`)
 95 95 | 
 96 96 | def f():
 
+RUF100_0.py:107:12: RUF100 [*] Unused `noqa` directive (unknown: `E50`)
+    |
+105 | def f():
+106 |     # Invalid - nonexistant error code with multibyte character
+107 |     d = 1  #…noqa: F841, E50
+    |            ^^^^^^^^^^^^^^^^ RUF100
+108 |     e = 1  #…noqa: E50
+    |
+    = help: Remove unused `noqa` directive
 
+ℹ Safe fix
+104 104 | 
+105 105 | def f():
+106 106 |     # Invalid - nonexistant error code with multibyte character
+107     |-    d = 1  #…noqa: F841, E50
+    107 |+    d = 1  # noqa: F841
+108 108 |     e = 1  #…noqa: E50
+
+RUF100_0.py:108:5: F841 [*] Local variable `e` is assigned to but never used
+    |
+106 |     # Invalid - nonexistant error code with multibyte character
+107 |     d = 1  #…noqa: F841, E50
+108 |     e = 1  #…noqa: E50
+    |     ^ F841
+    |
+    = help: Remove assignment to unused variable `e`
+
+ℹ Unsafe fix
+105 105 | def f():
+106 106 |     # Invalid - nonexistant error code with multibyte character
+107 107 |     d = 1  #…noqa: F841, E50
+108     |-    e = 1  #…noqa: E50
+
+RUF100_0.py:108:12: RUF100 [*] Unused `noqa` directive (unknown: `E50`)
+    |
+106 |     # Invalid - nonexistant error code with multibyte character
+107 |     d = 1  #…noqa: F841, E50
+108 |     e = 1  #…noqa: E50
+    |            ^^^^^^^^^^ RUF100
+    |
+    = help: Remove unused `noqa` directive
+
+ℹ Safe fix
+105 105 | def f():
+106 106 |     # Invalid - nonexistant error code with multibyte character
+107 107 |     d = 1  #…noqa: F841, E50
+108     |-    e = 1  #…noqa: E50
+    108 |+    e = 1