qmlformat: Make arrow functions one liners

Fixes: QTBUG-87179
Change-Id: Ieb7dffab59923bcb2ce8745c499eff7de44134b1
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

4 files changed, 28 insertions, 4 deletions

diff --git a/tests/auto/qml/qmlformat/data/arrowFunctions.formatted.qml b/tests/auto/qml/qmlformat/data/arrowFunctions.formatted.qml
new file mode 100644
index 0000000000..e4bc1f6747
--- /dev/null
+++ b/tests/auto/qml/qmlformat/data/arrowFunctions.formatted.qml
@@ -0,0 +1,5 @@
+Item {
+    arrow1: (x) => x
+    arrow2: (x) => x + x
+    arrow3: () => x > 3 ? x * x : x
+}
diff --git a/tests/auto/qml/qmlformat/data/arrowFunctions.qml b/tests/auto/qml/qmlformat/data/arrowFunctions.qml
new file mode 100644
index 0000000000..e4bc1f6747
--- /dev/null
+++ b/tests/auto/qml/qmlformat/data/arrowFunctions.qml
@@ -0,0 +1,5 @@
+Item {
+    arrow1: (x) => x
+    arrow2: (x) => x + x
+    arrow3: () => x > 3 ? x * x : x
+}
diff --git a/tests/auto/qml/qmlformat/tst_qmlformat.cpp b/tests/auto/qml/qmlformat/tst_qmlformat.cpp
index 45a51dec21..dfe41a77d8 100644
--- a/tests/auto/qml/qmlformat/tst_qmlformat.cpp
+++ b/tests/auto/qml/qmlformat/tst_qmlformat.cpp
@@ -237,6 +237,8 @@ void TestQmlformat::testFormat_data()
                                     << "propertyNames.formatted.qml" << false << true;
     QTest::newRow("empty object") << "emptyObject.qml"
                                   << "emptyObject.formatted.qml" << false << true;
+    QTest::newRow("arrow functions") << "arrowFunctions.qml"
+                                     << "arrowFunctions.formatted.qml" << false << true;
 }
 
 void TestQmlformat::testFormat()
diff --git a/tools/qmlformat/dumpastvisitor.cpp b/tools/qmlformat/dumpastvisitor.cpp
index 47ea76b119..24286ba69b 100644
--- a/tools/qmlformat/dumpastvisitor.cpp
+++ b/tools/qmlformat/dumpastvisitor.cpp
@@ -321,6 +321,7 @@ QString DumpAstVisitor::parseFunctionExpression(FunctionExpression *functExpr, b
 {
     m_indentLevel++;
     QString result;
+    bool hasBraces = true;
 
     if (!functExpr->isArrowFunction) {
         result += omitFunction ? "" : "function";
@@ -343,12 +344,23 @@ QString DumpAstVisitor::parseFunctionExpression(FunctionExpression *functExpr, b
          if (functExpr->typeAnnotation != nullptr)
              result += " : " + parseType(functExpr->typeAnnotation->type);
 
-         result += " => {\n" + parseStatementList(functExpr->body);
+         result += " => ";
+
+         if (functExpr->body == nullptr) {
+             result += "{}";
+         } else if (functExpr->body->next == nullptr && functExpr->body->statement->kind == Node::Kind_ReturnStatement) {
+             m_indentLevel--;
+             result += parseExpression(cast<ReturnStatement *>(functExpr->body->statement)->expression);
+             hasBraces = false;
+         } else {
+             result += "{\n" + parseStatementList(functExpr->body);
+         }
     }
 
-    m_indentLevel--;
-
-    result += formatLine("}", false);
+    if (hasBraces) {
+        m_indentLevel--;
+        result += formatLine("}", false);
+    }
 
     return result;