Preserve trailing semicolons when using fmt: off

crates/ruff_python_formatter/resources/test/fixtures/ruff/fmt_on_off/trailing_semicolon.py

@@ -0,0 +1,27 @@
+def f():
+    # fmt: off
+    a = 10
+
+    if True:
+        with_semicolon = 10   \
+            ;
+
+formatted   = true;
+
+
+def f():
+    # fmt: off
+
+    if True:
+        with_semicolon = 20 \
+            ; # comment
+
+
+# fmt: off
+statement = 0 \
+    ;
+# fmt: on
+a = 10
+
+# fmt: off
+last_statement_with_semi   ;

crates/ruff_python_formatter/src/lib.rs

@@ -206,13 +206,13 @@ if True:
     #[test]
     fn quick_test() {
         let source = r#"
-def main() -> None:
+def f():
+    # fmt: off
+
     if True:
-        some_very_long_variable_name_abcdefghijk = Foo()
-        some_very_long_variable_name_abcdefghijk = some_very_long_variable_name_abcdefghijk[
-            some_very_long_variable_name_abcdefghijk.some_very_long_attribute_name
-            == "This is a very long string abcdefghijk"
-        ]
+        with_semicolon = 20 \
+            ; # comment
+
 
 "#;
         let source_type = PySourceType::Python;

crates/ruff_python_formatter/src/verbatim.rs

@@ -395,14 +395,18 @@ fn write_suppressed_statements<'a>(
             statement = SuiteChildStatement::Other(next_statement);
             leading_node_comments = comments.leading(next_statement);
         } else {
-            let mut nodes =
-                std::iter::successors(Some(AnyNodeRef::from(statement.statement())), |statement| {
-                    statement.last_child_in_body()
-                });
-
-            let end = nodes
-                .find_map(|statement| comments.trailing(statement).last().map(Ranged::end))
-                .unwrap_or(statement.end());
+            let mut current = AnyNodeRef::from(statement.statement());
+            // Expand the range of the statement to include any trailing comments or semicolons.
+            let end = loop {
+                if let Some(comment) = comments.trailing(current).last() {
+                    break comment.end();
+                } else if let Some(child) = AnyNodeRef::from(current).last_child_in_body() {
+                    current = child;
+                } else {
+                    break trailing_semicolon(current, source)
+                        .map_or(statement.end(), TextRange::end);
+                }
+            };
 
             FormatVerbatimStatementRange {
                 verbatim_range: TextRange::new(format_off_comment.end(), end),

crates/ruff_python_formatter/tests/snapshots/format@fmt_on_off__trailing_semicolon.py.snap

@@ -0,0 +1,69 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+input_file: crates/ruff_python_formatter/resources/test/fixtures/ruff/fmt_on_off/trailing_semicolon.py
+---
+## Input
+```py
+def f():
+    # fmt: off
+    a = 10
+
+    if True:
+        with_semicolon = 10   \
+            ;
+
+formatted   = true;
+
+
+def f():
+    # fmt: off
+
+    if True:
+        with_semicolon = 20 \
+            ; # comment
+
+
+# fmt: off
+statement = 0 \
+    ;
+# fmt: on
+a = 10
+
+# fmt: off
+last_statement_with_semi   ;
+```
+
+## Output
+```py
+def f():
+    # fmt: off
+    a = 10
+
+    if True:
+        with_semicolon = 10   \
+            ;
+
+
+formatted = true
+
+
+def f():
+    # fmt: off
+
+    if True:
+        with_semicolon = 20 \
+            ; # comment
+
+
+# fmt: off
+statement = 0 \
+    ;
+# fmt: on
+a = 10
+
+# fmt: off
+last_statement_with_semi   ;
+```
+
+
+