Defer changes for zero argument functions until style_edition=2027

src/config/options.rs

@@ -536,7 +536,16 @@ impl From<StyleEdition> for rustc_span::edition::Edition {
 
 impl PartialOrd for StyleEdition {
     fn partial_cmp(&self, other: &StyleEdition) -> Option<std::cmp::Ordering> {
-        rustc_span::edition::Edition::partial_cmp(&(*self).into(), &(*other).into())
+        // FIXME(ytmimi): Update `StyleEdition::Edition2027` logic when
+        // `rustc_span::edition::Edition::Edition2027` becomes available in the compiler
+        match (self, other) {
+            (Self::Edition2027, Self::Edition2027) => Some(std::cmp::Ordering::Equal),
+            (_, Self::Edition2027) => Some(std::cmp::Ordering::Less),
+            (Self::Edition2027, _) => Some(std::cmp::Ordering::Greater),
+            (Self::Edition2015 | Self::Edition2018 | Self::Edition2021 | Self::Edition2024, _) => {
+                rustc_span::edition::Edition::partial_cmp(&(*self).into(), &(*other).into())
+            }
+        }
     }
 }
 
@@ -684,3 +693,41 @@ config_option_with_style_edition_default!(
     MakeBackup, bool, _ => false;
     PrintMisformattedFileNames, bool, _ => false;
 );
+
+#[test]
+fn style_edition_comparisons() {
+    // Style Edition 2015
+    assert!(StyleEdition::Edition2015 == StyleEdition::Edition2015);
+    assert!(StyleEdition::Edition2015 < StyleEdition::Edition2018);
+    assert!(StyleEdition::Edition2015 < StyleEdition::Edition2021);
+    assert!(StyleEdition::Edition2015 < StyleEdition::Edition2024);
+    assert!(StyleEdition::Edition2015 < StyleEdition::Edition2027);
+
+    // Style Edition 2018
+    assert!(StyleEdition::Edition2018 > StyleEdition::Edition2015);
+    assert!(StyleEdition::Edition2018 == StyleEdition::Edition2018);
+    assert!(StyleEdition::Edition2018 < StyleEdition::Edition2021);
+    assert!(StyleEdition::Edition2018 < StyleEdition::Edition2024);
+    assert!(StyleEdition::Edition2018 < StyleEdition::Edition2027);
+
+    // Style Edition 2021
+    assert!(StyleEdition::Edition2021 > StyleEdition::Edition2015);
+    assert!(StyleEdition::Edition2021 > StyleEdition::Edition2018);
+    assert!(StyleEdition::Edition2021 == StyleEdition::Edition2021);
+    assert!(StyleEdition::Edition2021 < StyleEdition::Edition2024);
+    assert!(StyleEdition::Edition2021 < StyleEdition::Edition2027);
+
+    // Style Edition 2024
+    assert!(StyleEdition::Edition2024 > StyleEdition::Edition2015);
+    assert!(StyleEdition::Edition2024 > StyleEdition::Edition2018);
+    assert!(StyleEdition::Edition2024 > StyleEdition::Edition2021);
+    assert!(StyleEdition::Edition2024 == StyleEdition::Edition2024);
+    assert!(StyleEdition::Edition2024 < StyleEdition::Edition2027);
+
+    // Style Edition 2024
+    assert!(StyleEdition::Edition2027 > StyleEdition::Edition2015);
+    assert!(StyleEdition::Edition2027 > StyleEdition::Edition2018);
+    assert!(StyleEdition::Edition2027 > StyleEdition::Edition2021);
+    assert!(StyleEdition::Edition2027 > StyleEdition::Edition2024);
+    assert!(StyleEdition::Edition2027 == StyleEdition::Edition2027);
+}

src/items.rs

@@ -2570,7 +2570,7 @@ fn rewrite_fn_base(
             .last()
             .map_or(false, |last_line| last_line.contains("//"));
 
-        if context.config.style_edition() >= StyleEdition::Edition2024 {
+        if context.config.style_edition() >= StyleEdition::Edition2027 {
             if closing_paren_overflow_max_width {
                 result.push(')');
                 result.push_str(&indent.to_string_with_newline(context.config));

tests/target/issue-3278/version_two.rs → tests/source/issue-3278/style_edition_2027.rs

@@ -1,4 +1,4 @@
-// rustfmt-style_edition: 2024
+// rustfmt-style_edition: 2027
 
 pub fn parse_conditional<'a, I: 'a>()
 -> impl Parser<Input = I, Output = Expr, PartialState = ()> + 'a

tests/source/long-fn-1/style_edition_2027.rs

@@ -0,0 +1,21 @@
+// rustfmt-style_edition: 2027
+// Tests that a function which is almost short enough, but not quite, gets
+// formatted correctly.
+
+impl Foo {
+    fn some_input(&mut self, input: Input, input_path: Option<PathBuf>, ) -> (Input, Option<PathBuf>) {}
+
+    fn some_inpu(&mut self, input: Input, input_path: Option<PathBuf>) -> (Input, Option<PathBuf>) {}
+}
+
+// #1843
+#[allow(non_snake_case)]
+pub extern "C" fn Java_com_exonum_binding_storage_indices_ValueSetIndexProxy_nativeContainsByHash() -> bool {
+    false
+}
+
+// #3009
+impl Something {
+    fn my_function_name_is_way_to_long_but_used_as_a_case_study_or_an_example_its_fine(
+) -> Result<  (), String  > {}
+}

tests/target/issue-3278/style_edition_2024.rs

@@ -0,0 +1,8 @@
+// rustfmt-style_edition: 2024
+
+pub fn parse_conditional<'a, I: 'a>(
+) -> impl Parser<Input = I, Output = Expr, PartialState = ()> + 'a
+where
+    I: Stream<Item = char>,
+{
+}

tests/target/issue-3278/style_edition_2027.rs

@@ -0,0 +1,8 @@
+// rustfmt-style_edition: 2027
+
+pub fn parse_conditional<'a, I: 'a>()
+-> impl Parser<Input = I, Output = Expr, PartialState = ()> + 'a
+where
+    I: Stream<Item = char>,
+{
+}

tests/target/long-fn-1/style_edition_2024.rs

@@ -0,0 +1,29 @@
+// rustfmt-style_edition: 2024
+// Tests that a function which is almost short enough, but not quite, gets
+// formatted correctly.
+
+impl Foo {
+    fn some_input(
+        &mut self,
+        input: Input,
+        input_path: Option<PathBuf>,
+    ) -> (Input, Option<PathBuf>) {
+    }
+
+    fn some_inpu(&mut self, input: Input, input_path: Option<PathBuf>) -> (Input, Option<PathBuf>) {
+    }
+}
+
+// #1843
+#[allow(non_snake_case)]
+pub extern "C" fn Java_com_exonum_binding_storage_indices_ValueSetIndexProxy_nativeContainsByHash(
+) -> bool {
+    false
+}
+
+// #3009
+impl Something {
+    fn my_function_name_is_way_to_long_but_used_as_a_case_study_or_an_example_its_fine(
+    ) -> Result<(), String> {
+    }
+}

tests/target/long-fn-1/version_two.rs → tests/target/long-fn-1/style_edition_2027.rs

@@ -1,4 +1,4 @@
-// rustfmt-style_edition: 2024
+// rustfmt-style_edition: 2027
 // Tests that a function which is almost short enough, but not quite, gets
 // formatted correctly.