Fix hanging expression formatting bug leading to syntax error

Fixes #135

Author: JohnnyMorganz

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Fixed
+- Fixed bug where a hanging expression inside of parentheses would lead to function arguments being incorrectly formatted with a trailing comma - leading to a syntax error
 
 ## [0.8.0] - 2021-04-30
 ### Added

src/formatters/expression.rs

@@ -439,15 +439,17 @@ fn format_hanging_expression_<'ast>(
                 format_hanging_expression_(ctx, expression, shape, indent_level)
             } else {
                 let contained = format_contained_span(ctx, &contained);
-                let expression = format_expression(ctx, expression, shape + 1); // 1 = opening parentheses
 
+                // Provide a sample formatting to see how large it is
                 // Examine the expression itself to see if needs to be split onto multiple lines
-                let expression_str = expression.to_string();
+                let formatted_expression = format_expression(ctx, expression, shape + 1); // 1 = opening parentheses
+
+                let expression_str = formatted_expression.to_string();
                 if !shape.add_width(2 + expression_str.len()).over_budget() {
                     // The expression inside the parentheses is small, we do not need to break it down further
                     return Expression::Parentheses {
                         contained,
-                        expression: Box::new(expression),
+                        expression: Box::new(formatted_expression),
                     };
                 }
 
@@ -480,7 +482,6 @@ fn format_hanging_expression_<'ast>(
         Expression::UnaryOperator { unop, expression } => {
             let unop = format_unop(ctx, unop);
             let shape = shape + strip_leading_trivia(&unop).to_string().len();
-            let expression = format_expression(ctx, expression, shape);
             let expression = format_hanging_expression_(ctx, &expression, shape, indent_level);
 
             Expression::UnaryOperator {

tests/inputs/multiline-expressions-4.lua

@@ -0,0 +1,5 @@
+function SetCallsign(Player, Callsign)
+	if Settings.PolicingSetup.Radio or (table.find(Settings.PolicingSetup.CallsignPrefix, string.sub(Callsign, 1, 2)) and tonumber(string.sub(Callsign, 3, 4))) then
+		Player:SetAttribute("Callsign", Callsign)
+	end
+end

tests/snapshots/tests__standard@multiline-expressions-4.lua.snap

@@ -0,0 +1,17 @@
+---
+source: tests/tests.rs
+expression: format(&contents)
+
+---
+function SetCallsign(Player, Callsign)
+	if
+		Settings.PolicingSetup.Radio
+		or (
+			table.find(Settings.PolicingSetup.CallsignPrefix, string.sub(Callsign, 1, 2))
+			and tonumber(string.sub(Callsign, 3, 4))
+		)
+	then
+		Player:SetAttribute("Callsign", Callsign)
+	end
+end
+