Suppress RUF027 fix for f-strings with comments targeting Python < 3.12

crates/ruff_linter/resources/test/fixtures/ruff/RUF027_0.py

@@ -90,3 +90,11 @@ def fuzz_bug():
 def backslash_test():
     x = "test"
     print("Hello {'\\n'}{x}")  # Should not trigger RUF027 for Python < 3.12
+
+# Test case for comment handling in f-string interpolations
+# Should not trigger RUF027 for Python < 3.12 due to comments in interpolations
+# https://github.com/astral-sh/ruff/issues/23460
+def comment_test():
+    x = "!"
+    print("""{x  # }
+}""")

crates/ruff_linter/src/rules/ruff/rules/missing_fstring_syntax.rs

@@ -226,10 +226,13 @@ fn should_be_fstring(
     for f_string in value.f_strings() {
         let mut has_name = false;
         for element in f_string.elements.interpolations() {
-            // Check if the interpolation expression contains backslashes
-            // F-strings with backslashes in interpolations are only valid in Python 3.12+
+            // F-strings with backslashes or comments in interpolations are only
+            // valid in Python 3.12+ (PEP 701)
             let interpolation_text = &fstring_expr[element.range()];
-            if target_version < PythonVersion::PY312 && interpolation_text.contains('\\') {
+            if target_version < PythonVersion::PY312
+                && (interpolation_text.contains('\\')
+                    || interpolation_text.contains('#'))
+            {
                 return false;
             }
 

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF027_RUF027_0.py.snap

@@ -328,11 +328,35 @@ RUF027 [*] Possible f-string without an `f` prefix
 91 |     x = "test"
 92 |     print("Hello {'\\n'}{x}")  # Should not trigger RUF027 for Python < 3.12
    |           ^^^^^^^^^^^^^^^^^^
+93 |
+94 | # Test case for comment handling in f-string interpolations
    |
 help: Add `f` prefix
 89 | # Should not trigger RUF027 for Python < 3.12 due to backslashes in interpolations
 90 | def backslash_test():
 91 |     x = "test"
    -     print("Hello {'\\n'}{x}")  # Should not trigger RUF027 for Python < 3.12
 92 +     print(f"Hello {'\\n'}{x}")  # Should not trigger RUF027 for Python < 3.12
+93 | 
+94 | # Test case for comment handling in f-string interpolations
+95 | # Should not trigger RUF027 for Python < 3.12 due to comments in interpolations
+note: This is an unsafe fix and may change runtime behavior
+
+RUF027 [*] Possible f-string without an `f` prefix
+   --> RUF027_0.py:99:11
+    |
+ 97 |   def comment_test():
+ 98 |       x = "!"
+ 99 |       print("""{x  # }
+    |  ___________^
+100 | | }""")
+    | |____^
+    |
+help: Add `f` prefix
+96  | # https://github.com/astral-sh/ruff/issues/23460
+97  | def comment_test():
+98  |     x = "!"
+    -     print("""{x  # }
+99  +     print(f"""{x  # }
+100 | }""")
 note: This is an unsafe fix and may change runtime behavior

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__missing_fstring_syntax_backslash_py311.snap

@@ -6,10 +6,33 @@ source: crates/ruff_linter/src/rules/ruff/mod.rs
 +linter.unresolved_target_version = 3.11
 
 --- Summary ---
-Removed: 2
+Removed: 4
 Added: 0
 
 --- Removed ---
+RUF027 [*] Possible f-string without an `f` prefix
+  --> RUF027_0.py:41:22
+   |
+39 |       single_line = """ {a} """  # RUF027
+40 |       # RUF027
+41 |       multi_line = a = """b { # comment
+   |  ______________________^
+42 | |     c}  d
+43 | |     """
+   | |_______^
+   |
+help: Add `f` prefix
+38 |     c = a
+39 |     single_line = """ {a} """  # RUF027
+40 |     # RUF027
+   -     multi_line = a = """b { # comment
+41 +     multi_line = a = f"""b { # comment
+42 |     c}  d
+43 |     """
+44 | 
+note: This is an unsafe fix and may change runtime behavior
+
+
 RUF027 [*] Possible f-string without an `f` prefix
   --> RUF027_0.py:49:9
    |
@@ -40,11 +63,36 @@ RUF027 [*] Possible f-string without an `f` prefix
 91 |     x = "test"
 92 |     print("Hello {'\\n'}{x}")  # Should not trigger RUF027 for Python < 3.12
    |           ^^^^^^^^^^^^^^^^^^
+93 |
+94 | # Test case for comment handling in f-string interpolations
    |
 help: Add `f` prefix
 89 | # Should not trigger RUF027 for Python < 3.12 due to backslashes in interpolations
 90 | def backslash_test():
 91 |     x = "test"
    -     print("Hello {'\\n'}{x}")  # Should not trigger RUF027 for Python < 3.12
 92 +     print(f"Hello {'\\n'}{x}")  # Should not trigger RUF027 for Python < 3.12
+93 | 
+94 | # Test case for comment handling in f-string interpolations
+95 | # Should not trigger RUF027 for Python < 3.12 due to comments in interpolations
+note: This is an unsafe fix and may change runtime behavior
+
+
+RUF027 [*] Possible f-string without an `f` prefix
+   --> RUF027_0.py:99:11
+    |
+ 97 |   def comment_test():
+ 98 |       x = "!"
+ 99 |       print("""{x  # }
+    |  ___________^
+100 | | }""")
+    | |____^
+    |
+help: Add `f` prefix
+96  | # https://github.com/astral-sh/ruff/issues/23460
+97  | def comment_test():
+98  |     x = "!"
+    -     print("""{x  # }
+99  +     print(f"""{x  # }
+100 | }""")
 note: This is an unsafe fix and may change runtime behavior