Fix module dependency handling

The evaluation of a module can have side-effects by modifying the global
object or objects in it. Therefore even a seemingly empty import such as

    import "./foo.js"

needs to be listed in the module requests. It's also important that they
are evaluated in the order of declaration. Therefore we collect all
module requests separately - even those that don't have import variables
to process. This patch also ensures that the export and import
declarations are visited in the correct order, by unifying both AST
nodes to be hooked into the statement list.

The fact that we connect the module list items into a statement list is
solely an artifact of re-using defineFunction() which takes a
StatementList as body.

Change-Id: I75dc357b2aecfc324d9a9fe66952eff1ec1dfd8a
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

3 files changed, 13 insertions, 26 deletions

diff --git a/src/qml/parser/qqmljsast.cpp b/src/qml/parser/qqmljsast.cpp
index 0b1b97a41a..ca4317a9a6 100644
--- a/src/qml/parser/qqmljsast.cpp
+++ b/src/qml/parser/qqmljsast.cpp
@@ -1162,26 +1162,10 @@ void ExportDeclaration::accept0(Visitor *visitor)
     visitor->endVisit(this);
 }
 
-void ModuleItemList::accept0(Visitor *visitor)
-{
-    if (visitor->visit(this)) {
-        for (ModuleItemList *it = this; it; it = it->next) {
-            if (it->item) {
-                // The statement list is concatenated together between module list
-                // items and stored in the ESModule, thus not visited from there.
-                if (it->item->kind == Kind_StatementList)
-                    continue;
-                // Export declaration are also injected into the statement list for
-                // processing of declarations an variable statements, so don't visit
-                // it here to avoid double visits.
-                if (it->item->kind == Kind_ExportDeclaration)
-                    continue;
-            }
-            accept(it->item, visitor);
-        }
-    }
-
-    visitor->endVisit(this);
+void ModuleItemList::accept0(Visitor *)
+{
+    // See ESModule::accept0
+    Q_UNREACHABLE();
 }
 
 StatementList *ModuleItemList::buildStatementList(MemoryPool *pool) const
@@ -1192,6 +1176,8 @@ StatementList *ModuleItemList::buildStatementList(MemoryPool *pool) const
         if (!listItem) {
             if (AST::ExportDeclaration *exportDecl = AST::cast<AST::ExportDeclaration*>(item->item))
                 listItem = new (pool) AST::StatementList(exportDecl);
+            else if (AST::ImportDeclaration *importDecl = AST::cast<AST::ImportDeclaration*>(item->item))
+                listItem = new (pool) AST::StatementList(importDecl);
             else
                 continue;
         }
@@ -1209,7 +1195,11 @@ StatementList *ModuleItemList::buildStatementList(MemoryPool *pool) const
 void ESModule::accept0(Visitor *visitor)
 {
     if (visitor->visit(this)) {
-        accept(body, visitor);
+        // We don't accept the ModuleItemList (body) as instead the statement list items
+        // as well as the import/export declarations are linked together in the statement
+        // list. That way they are processed in correct order and can be used with the codegen's
+        // defineFunction() that expects a statement list.
+        // accept(body, visitor);
         accept(statements, visitor);
     }
 
diff --git a/src/qml/parser/qqmljsast_p.h b/src/qml/parser/qqmljsast_p.h
index e344dd4a28..1429d784c6 100644
--- a/src/qml/parser/qqmljsast_p.h
+++ b/src/qml/parser/qqmljsast_p.h
@@ -2539,7 +2539,7 @@ public:
     QStringRef moduleSpecifier;
 };
 
-class QML_PARSER_EXPORT ImportDeclaration: public Node
+class QML_PARSER_EXPORT ImportDeclaration: public Statement
 {
 public:
     QQMLJS_DECLARE_AST_NODE(ImportDeclaration)
@@ -2755,7 +2755,7 @@ public:
 
     StatementList *buildStatementList(MemoryPool *pool) const;
 
-    void accept0(Visitor *visitor) override;
+    void accept0(Visitor *) override;
 
     SourceLocation firstSourceLocation() const override
     { return item->firstSourceLocation(); }
diff --git a/src/qml/parser/qqmljsastvisitor_p.h b/src/qml/parser/qqmljsastvisitor_p.h
index 3162bb1630..c925096de6 100644
--- a/src/qml/parser/qqmljsastvisitor_p.h
+++ b/src/qml/parser/qqmljsastvisitor_p.h
@@ -369,9 +369,6 @@ public:
     virtual bool visit(ModuleItem *) { return true; }
     virtual void endVisit(ModuleItem *) {}
 
-    virtual bool visit(ModuleItemList *) { return true; }
-    virtual void endVisit(ModuleItemList *) {}
-
     virtual bool visit(ESModule *) { return true; }
     virtual void endVisit(ESModule *) {}