WIP: Attempt to break long expressions into multiple lines

Fixes #3474

swayfmt/src/formatter/shape.rs

@@ -112,6 +112,8 @@ pub(crate) struct CodeLine {
     pub(crate) expr_kind: ExprKind,
     /// Used in determining `SameLineWhere` formatting.
     pub(crate) has_where_clause: bool,
+    /// Expression is too long to fit in a single line
+    pub(crate) expr_new_line: bool,
 }
 
 impl CodeLine {
@@ -121,6 +123,7 @@ impl CodeLine {
             line_style,
             expr_kind,
             has_where_clause: Default::default(),
+            expr_new_line: false,
         }
     }
     pub(crate) fn reset_width(&mut self) {
@@ -147,6 +150,10 @@ impl CodeLine {
     pub(crate) fn update_where_clause(&mut self, has_where_clause: bool) {
         self.has_where_clause = has_where_clause;
     }
+
+    pub(crate) fn update_expr_new_line(&mut self, expr_new_line: bool) {
+        self.expr_new_line = expr_new_line;
+    }
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
@@ -300,10 +307,9 @@ impl Shape {
     }
     /// Create a new `Shape` with default `CodeLine`.
     pub(crate) fn with_default_code_line(self) -> Self {
-        Self {
-            code_line: CodeLine::default(),
-            ..self
-        }
+        let mut code_line = CodeLine::default();
+        code_line.update_expr_new_line(self.code_line.expr_new_line);
+        Self { code_line, ..self }
     }
 }
 

swayfmt/src/utils/language/expr/mod.rs

@@ -275,8 +275,20 @@ impl Format for Expr {
                 name,
             } => {
                 target.format(formatted_code, formatter)?;
-                write!(formatted_code, "{}", dot_token.span().as_str())?;
-                name.format(formatted_code, formatter)?;
+                if formatter.shape.code_line.expr_new_line {
+                    formatter.indent();
+                    write!(
+                        formatted_code,
+                        "\n{}{}",
+                        formatter.indent_to_str()?,
+                        dot_token.span().as_str()
+                    )?;
+                    name.format(formatted_code, formatter)?;
+                    formatter.unindent();
+                } else {
+                    write!(formatted_code, "{}", dot_token.span().as_str())?;
+                    name.format(formatted_code, formatter)?;
+                }
             }
             Self::TupleFieldProjection {
                 target,
@@ -646,6 +658,13 @@ fn format_method_call(
         write!(formatted_code, "{}", formatter.indent_to_str()?)?;
     }
     target.format(formatted_code, formatter)?;
+
+    if formatter.shape.code_line.expr_new_line {
+        formatter.indent();
+        write!(formatted_code, "\n{}", formatter.indent_to_str()?)?;
+        formatter.unindent();
+    }
+
     write!(formatted_code, "{}", dot_token.span().as_str())?;
     path_seg.format(formatted_code, formatter)?;
     if let Some(contract_args) = &contract_args_opt {

swayfmt/src/utils/language/statement.rs

@@ -31,7 +31,16 @@ fn format_statement(
             expr,
             semicolon_token_opt,
         } => {
-            expr.format(formatted_code, formatter)?;
+            let mut temp_expr = FormattedCode::new();
+            expr.format(&mut temp_expr, formatter)?;
+            if temp_expr.len() > formatter.config.whitespace.max_width {
+                formatter.shape.code_line.expr_new_line = true;
+                // reformat the expression adding a break
+                expr.format(formatted_code, formatter)?;
+                formatter.shape.code_line.expr_new_line = false;
+            } else {
+                write!(formatted_code, "{}", temp_expr)?;
+            }
             if let Some(semicolon) = semicolon_token_opt {
                 if formatter.shape.code_line.line_style == LineStyle::Inline {
                     write!(formatted_code, "{}", semicolon.span().as_str())?;

swayfmt/tests/mod.rs

@@ -1716,3 +1716,51 @@ impl OrdEq for u256 {}
 "#,
     );
 }
+
+#[test]
+fn chained_methods() {
+    check(
+        r#"
+library;
+
+fn test() {
+    fuelcoin.really_long_field.other_really_long_field.foo().bar().baz.quux().yet_another_call().to_go_above_max_line_length();
+}
+        "#,
+        r#"library;
+
+fn test() {
+    fuelcoin
+        .really_long_field
+        .other_really_long_field
+        .foo()
+        .bar()
+        .baz
+        .quux()
+        .yet_another_call()
+        .to_go_above_max_line_length();
+}
+"#,
+    );
+}
+
+#[test]
+fn comment_in_the_middle() {
+    check(
+        r#"
+        library;
+
+        fn test() {
+            let number: /* this number is for counting */ u64 = 10;
+
+
+
+        }"#,
+        r#"library;
+
+fn test() {
+    let number: /* this number is for counting */ u64 = 10;
+}
+"#,
+    );
+}