[pyupgrade] Make fix unsafe if it deletes comments (UP020)

crates/ruff_linter/resources/test/fixtures/pyupgrade/UP020.py

@@ -7,3 +7,11 @@
 
 with open("f.txt") as f:
     print(f.read())
+
+
+with (
+    io  # text
+    # text
+    .open("file.txt") as f
+):
+    ...

crates/ruff_linter/src/rules/pyupgrade/rules/open_alias.rs

@@ -1,3 +1,4 @@
+use ruff_diagnostics::Applicability;
 use ruff_python_ast::Expr;
 
 use ruff_macros::{ViolationMetadata, derive_message_formats};
@@ -26,6 +27,8 @@ use crate::{Edit, Fix, FixAvailability, Violation};
 /// with open("file.txt") as f:
 ///     ...
 /// ```
+/// ## Fix safety
+/// This rule's fix is marked as safe, unless the expression contains comments.
 ///
 /// ## References
 /// - [Python documentation: `io.open`](https://docs.python.org/3/library/io.html#io.open)
@@ -60,9 +63,17 @@ pub(crate) fn open_alias(checker: &Checker, expr: &Expr, func: &Expr) {
                 expr.start(),
                 checker.semantic(),
             )?;
-            Ok(Fix::safe_edits(
+
+            let applicability = if checker.comment_ranges().intersects(func.range()) {
+                Applicability::Unsafe
+            } else {
+                Applicability::Safe
+            };
+
+            Ok(Fix::applicable_edits(
                 Edit::range_replacement(binding, func.range()),
                 import_edit,
+                applicability,
             ))
         });
     }

crates/ruff_linter/src/rules/pyupgrade/snapshots/ruff_linter__rules__pyupgrade__tests__UP020.py.snap

@@ -37,3 +37,35 @@ help: Replace with builtin `open`
    - with open("f.txt") as f:
 9  + with builtins.open("f.txt") as f:
 10 |     print(f.read())
+11 | 
+12 | 
+
+UP020 [*] Use builtin `open`
+  --> UP020.py:13:5
+   |
+12 |   with (
+13 | /     io  # text
+14 | |     # text
+15 | |     .open("file.txt") as f
+   | |_____________________^
+16 |   ):
+17 |       ...
+   |
+help: Replace with builtin `open`
+4  |     print(f.read())
+5  | 
+6  | from io import open
+7  + import builtins
+8  | 
+9  | with open("f.txt") as f:
+10 |     print(f.read())
+11 | 
+12 | 
+13 | with (
+   -     io  # text
+   -     # text
+   -     .open("file.txt") as f
+14 +     builtins.open("file.txt") as f
+15 | ):
+16 |     ...
+note: This is an unsafe fix and may change runtime behavior