1 files changed, 107 insertions, 28 deletions

diff --git a/src/qmldom/qqmldomreformatter.cpp b/src/qmldom/qqmldomreformatter.cpp
index 9576e3c8cb..1f8337ac71 100644
--- a/src/qmldom/qqmldomreformatter.cpp
+++ b/src/qmldom/qqmldomreformatter.cpp
@@ -10,9 +10,7 @@
 #include <QtQml/private/qqmljslexer_p.h>
 
 #include <QString>
-
 #include <algorithm>
-#include <limits>
 
 QT_BEGIN_NAMESPACE
 namespace QQmlJS {
@@ -46,6 +44,10 @@ void ScriptFormatter::lnAcceptIndented(Node *node)
 
 bool ScriptFormatter::acceptBlockOrIndented(Node *ast, bool finishWithSpaceOrNewline)
 {
+    if (auto *es = cast<EmptyStatement *>(ast)) {
+        writeOutSemicolon(es);
+        return false;
+    }
     if (cast<Block *>(ast)) {
         lw.lineWriter.ensureSpace();
         accept(ast);
@@ -92,7 +94,7 @@ bool ScriptFormatter::visit(StringLiteral *ast)
     // correctly handle multiline literals
     if (ast->literalToken.length == 0)
         return true;
-    QStringView str = loc2Str(ast->literalToken);
+    QStringView str = m_script->loc2Str(ast->literalToken);
     if (lw.indentNextlines && str.contains(QLatin1Char('\n'))) {
         out(str.mid(0, 1));
         lw.indentNextlines = false;
@@ -288,7 +290,7 @@ bool ScriptFormatter::visit(TemplateLiteral *ast)
 {
     // correctly handle multiline literals
     if (ast->literalToken.length != 0) {
-        QStringView str = loc2Str(ast->literalToken);
+        QStringView str = m_script->loc2Str(ast->literalToken);
         if (lw.indentNextlines && str.contains(QLatin1Char('\n'))) {
             out(str.mid(0, 1));
             lw.indentNextlines = false;
@@ -474,7 +476,7 @@ bool ScriptFormatter::visit(VariableStatement *ast)
     lw.lineWriter.ensureSpace();
     accept(ast->declarations);
     if (addSemicolons())
-        out(";");
+        writeOutSemicolon(ast);
     return false;
 }
 
@@ -512,9 +514,9 @@ bool ScriptFormatter::visit(PatternElement *ast)
     return false;
 }
 
-bool ScriptFormatter::visit(EmptyStatement *ast)
+bool ScriptFormatter::visit(EmptyStatement *)
 {
-    out(ast->semicolonToken);
+    lw.lineWriter.ensureSemicolon();
     return false;
 }
 
@@ -575,14 +577,21 @@ bool ScriptFormatter::visit(ForStatement *ast)
             out(pe->declarationKindToken);
             lw.lineWriter.ensureSpace();
         }
+        bool first = true;
         for (VariableDeclarationList *it = ast->declarations; it; it = it->next) {
+            if (!std::exchange(first, false)) {
+                out(",");
+                lw.lineWriter.ensureSpace();
+            }
             accept(it->declaration);
         }
     }
-    out(";"); // ast->firstSemicolonToken
+    // We don't use writeOutSemicolon() here because we need a semicolon unconditionally.
+    // Repeats for the second semicolon token below.
+    out(u";"); // ast->firstSemicolonToken
     lw.lineWriter.ensureSpace();
     accept(ast->condition);
-    out(";"); // ast->secondSemicolonToken
+    out(u";"); // ast->secondSemicolonToken
     lw.lineWriter.ensureSpace();
     accept(ast->expression);
     out(ast->rparenToken);
@@ -617,7 +626,7 @@ bool ScriptFormatter::visit(ContinueStatement *ast)
         out(ast->identifierToken);
     }
     if (addSemicolons())
-        out(";");
+        writeOutSemicolon(ast);
     return false;
 }
 
@@ -629,7 +638,7 @@ bool ScriptFormatter::visit(BreakStatement *ast)
         out(ast->identifierToken);
     }
     if (addSemicolons())
-        out(";");
+        writeOutSemicolon(ast);
     return false;
 }
 
@@ -642,7 +651,7 @@ bool ScriptFormatter::visit(ReturnStatement *ast)
         accept(ast->expression);
     }
     if (ast->returnToken.length > 0 && addSemicolons())
-        out(";");
+        writeOutSemicolon(ast);
     return false;
 }
 
@@ -667,7 +676,7 @@ bool ScriptFormatter::visit(ThrowStatement *ast)
         accept(ast->expression);
     }
     if (addSemicolons())
-        out(";");
+        writeOutSemicolon(ast);
     return false;
 }
 
@@ -860,7 +869,7 @@ bool ScriptFormatter::visit(StatementList *ast)
     for (StatementList *it = ast; it; it = it->next) {
         // ### work around parser bug: skip empty statements with wrong tokens
         if (EmptyStatement *emptyStatement = cast<EmptyStatement *>(it->statement)) {
-            if (loc2Str(emptyStatement->semicolonToken) != QLatin1String(";"))
+            if (m_script->loc2Str(emptyStatement->semicolonToken) != QLatin1String(";"))
                 continue;
         }
 
@@ -935,7 +944,7 @@ bool ScriptFormatter::visit(ComputedPropertyName *)
     out("[");
     return true;
 }
-bool ScriptFormatter::visit(Expression *el)
+bool ScriptFormatter::visit(CommaExpression *el)
 {
     accept(el->left);
     out(",");
@@ -946,7 +955,7 @@ bool ScriptFormatter::visit(Expression *el)
 bool ScriptFormatter::visit(ExpressionStatement *el)
 {
     if (addSemicolons())
-        postOps[el->expression].append([this]() { out(";"); });
+        postOps[el->expression].append([this, el]() { writeOutSemicolon(el); });
     return true;
 }
 
@@ -1107,16 +1116,16 @@ void ScriptFormatter::endVisit(ComputedPropertyName *)
 void ScriptFormatter::endVisit(AST::ExportDeclaration *ast)
 {
     // add a semicolon at the end of the following expressions
-    // export * FromClause ;
+    // export * FromClause
     // export ExportClause FromClause ;
     if (ast->fromClause) {
-        out(";");
+        writeOutSemicolon(ast);
     }
 
     // add a semicolon at the end of the following expressions
     // export ExportClause ;
     if (ast->exportClause && !ast->fromClause) {
-        out(";");
+        writeOutSemicolon(ast);
     }
 
     // add a semicolon at the end of the following expressions
@@ -1125,7 +1134,7 @@ void ScriptFormatter::endVisit(AST::ExportDeclaration *ast)
         // lookahead ∉ { function, class }
         if (!(ast->variableStatementOrDeclaration->kind == Node::Kind_FunctionDeclaration
               || ast->variableStatementOrDeclaration->kind == Node::Kind_ClassDeclaration)) {
-            out(";");
+            writeOutSemicolon(ast);
         }
         // ArrowFunction in QQmlJS::AST is handled with the help of FunctionDeclaration
         // and not as part of AssignmentExpression (as per ECMA
@@ -1133,7 +1142,7 @@ void ScriptFormatter::endVisit(AST::ExportDeclaration *ast)
         if (ast->variableStatementOrDeclaration->kind == Node::Kind_FunctionDeclaration
             && static_cast<AST::FunctionDeclaration *>(ast->variableStatementOrDeclaration)
                        ->isArrowFunction) {
-            out(";");
+            writeOutSemicolon(ast);
         }
     }
 }
@@ -1154,9 +1163,9 @@ void ScriptFormatter::endVisit(AST::NamedImports *ast)
     out(ast->rightBraceToken);
 }
 
-void ScriptFormatter::endVisit(AST::ImportDeclaration *)
+void ScriptFormatter::endVisit(AST::ImportDeclaration *id)
 {
-    out(";");
+    writeOutSemicolon(id);
 }
 
 void ScriptFormatter::throwRecursionDepthError()
@@ -1164,14 +1173,84 @@ void ScriptFormatter::throwRecursionDepthError()
     out("/* ERROR: Hit recursion limit  ScriptFormatter::visiting AST, rewrite failed */");
 }
 
-void reformatAst(OutWriter &lw, const std::shared_ptr<AstComments> &comments,
-                 const std::function<QStringView(SourceLocation)> &loc2Str, AST::Node *n)
-{
-    if (n) {
-        ScriptFormatter formatter(lw, comments, loc2Str, n);
+// This is a set of characters that are not allowed to be at the beginning of a line
+// after a semicolon for ASI.
+using namespace Qt::StringLiterals;
+static constexpr QLatin1StringView restrictedChars = "([/+-"_L1;
+
+// Given an existing semicolon, can we safely remove it without changing behavior
+bool ScriptFormatter::canRemoveSemicolon(AST::Node *node)
+{
+    const auto canRelyOnASI = [this](Node *node) {
+        auto nodeLoc = node->lastSourceLocation().offset + 1;
+        auto code = m_script->engine()->code();
+        // Bounds check for nodeLoc
+        if (qsizetype(nodeLoc) >= code.size())
+            return false;
+        auto startIt = code.begin() + nodeLoc;
+        auto endIt = std::find_first_of(startIt, code.end(), restrictedChars.begin(),
+                                        restrictedChars.end());
+        // No restricted character found, then it is safe to remove the semicolon
+        if (endIt == code.end())
+            return true;
+
+        // Check if there is at least one character between nodeLoc and the found character
+        // that are neither space chars nor semicolons.
+        bool hasOtherChars =
+                std::any_of(startIt, endIt, [](QChar ch) { return !(ch.isSpace() || ch == u';'); });
+
+        if (hasOtherChars)
+            return true;
+
+        // Check if there is no linebreak between nodeLoc and the found character
+        return std::none_of(startIt, endIt, [](QChar c) { return c == u'\n'; });
+    };
+
+    // Check if the node is a statement that requires a semicolon to avoid ASI issues
+    switch (node->kind) {
+    case AST::Node::Kind_ExpressionStatement:
+        return canRelyOnASI(cast<ExpressionStatement *>(node));
+    case AST::Node::Kind_VariableStatement:
+        return canRelyOnASI(cast<VariableStatement *>(node));
+    case AST::Node::Kind_EmptyStatement:
+        return false;
+    case AST::Node::Kind_ContinueStatement:
+    case AST::Node::Kind_BreakStatement:
+    case AST::Node::Kind_ReturnStatement:
+    case AST::Node::Kind_ThrowStatement:
+    case AST::Node::Kind_ExportDeclaration:
+    case AST::Node::Kind_ImportDeclaration:
+    case AST::Node::Kind_FromClause:
+    case AST::Node::Kind_ExportClause:
+    default:
+        return true;
     }
 }
 
+OutWriter &ScriptFormatter::writeOutSemicolon(AST::Node *node)
+{
+    if (!node)
+        return lw;
+    switch (lw.lineWriter.options().semicolonRule) {
+    case LineWriterOptions::SemicolonRule::Essential:
+        if (!canRemoveSemicolon(node))
+            out(u";");
+        lw.lineWriter.ensureNewline();
+        return lw;
+    case LineWriterOptions::SemicolonRule::Always:
+        out(u";");
+        return lw;
+    default:
+        Q_UNREACHABLE_RETURN(lw);
+    }
+}
+
+void reformatAst(OutWriter &lw, const QQmlJS::Dom::ScriptExpression *const script)
+{
+    if (script)
+        ScriptFormatter formatter(lw, script);
+}
+
 } // namespace Dom
 } // namespace QQmlJS
 QT_END_NAMESPACE