Extend linter to check for unqualified ids

The linter has gained a new option (-U/--check-unqualified).
If run with this option, it warns about occurrences of unqualified identifiers.
Furthermore, it attempts to detect the reason for why the identifier can be
used unqalified:

- If the id originates from the root element, it suggests to qualify the
  access either with the root element's id, or with "parent" if applicable.

- If the id is the parameter of a signal, it suggests to use functions in the
  handler, instead of relying on the signal parameters to be "magically"
  injected into scope.

The linter does not attempt to handle with statements, but warns the
user instead that they are a bad idea.

Change-Id: I9aaf28c37595d84886a1071d49b86799b222a617
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 129 insertions, 0 deletions

diff --git a/tools/qmllint/findunqualified.h b/tools/qmllint/findunqualified.h
new file mode 100644
index 0000000000..937194d142
--- /dev/null
+++ b/tools/qmllint/findunqualified.h
@@ -0,0 +1,129 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the tools applications of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef FINDUNQUALIFIED_H
+#define FINDUNQUALIFIED_H
+
+#include "qmljstypedescriptionreader.h"
+#include "qcoloroutput_p.h"
+
+#include <private/qqmljsastvisitor_p.h>
+#include <private/qqmljsast_p.h>
+
+#include <QScopedPointer>
+
+class ScopeTree;
+enum class ScopeType;
+
+class FindUnqualifiedIDVisitor : public QQmlJS::AST::Visitor {
+
+public:
+    explicit FindUnqualifiedIDVisitor(QStringList const &qmltypeDirs, const QString& code, const QString& fileName);
+    ~FindUnqualifiedIDVisitor() override;
+    bool check();
+
+private:
+    QScopedPointer<ScopeTree> m_rootScope;
+    ScopeTree *m_currentScope;
+    QHash<QString, LanguageUtils::FakeMetaObject::ConstPtr> m_exportedName2MetaObject;
+    QStringList m_qmltypeDirs;
+    const QString& m_code;
+    QHash<QString, LanguageUtils::FakeMetaObject::ConstPtr> m_qmlid2meta;
+    QString m_rootId;
+    QString m_filePath;
+    QSet<QPair<QString, QString>> m_alreadySeenImports;
+    ColorOutput m_colorOut;
+
+    struct OutstandingConnection {QString targetName; ScopeTree *scope; QQmlJS::AST::UiObjectDefinition *uiod;};
+
+    QVarLengthArray<OutstandingConnection, 3> m_outstandingConnections; // Connections whose target we have not encountered
+
+    void enterEnvironment(ScopeType type, QString name);
+    void leaveEnvironment();
+    void importHelper(QString id, QString prefix, int major, int minor);
+    LanguageUtils::FakeMetaObject* localQmlFile2FakeMetaObject(QString filePath);
+
+
+    void importExportedNames(QStringRef prefix, QString name);
+
+    void throwRecursionDepthError() override;
+
+    // start block/scope handling
+    bool visit(QQmlJS::AST::UiProgram *ast) override;
+    void endVisit(QQmlJS::AST::UiProgram *ast) override;
+
+    bool visit(QQmlJS::AST::ClassExpression *ast) override;
+    void endVisit(QQmlJS::AST::ClassExpression *ast) override;
+
+    bool visit(QQmlJS::AST::ClassDeclaration *ast) override;
+    void endVisit(QQmlJS::AST::ClassDeclaration *ast) override;
+
+    bool visit(QQmlJS::AST::ForStatement *ast) override;
+    void endVisit(QQmlJS::AST::ForStatement *ast) override;
+
+    bool visit(QQmlJS::AST::ForEachStatement *ast) override;
+    void endVisit(QQmlJS::AST::ForEachStatement *ast) override;
+
+    bool visit(QQmlJS::AST::Block *ast) override;
+    void endVisit(QQmlJS::AST::Block *ast) override;
+
+    bool visit(QQmlJS::AST::CaseBlock *ast) override;
+    void endVisit(QQmlJS::AST::CaseBlock *ast) override;
+
+    bool visit(QQmlJS::AST::Catch *ast) override;
+    void endVisit(QQmlJS::AST::Catch *ast) override;
+
+    bool visit(QQmlJS::AST::WithStatement *withStatement) override;
+    void endVisit(QQmlJS::AST::WithStatement *ast) override;
+
+    void visitFunctionExpressionHelper(QQmlJS::AST::FunctionExpression *fexpr);
+    bool visit(QQmlJS::AST::FunctionExpression *fexpr) override;
+    void endVisit(QQmlJS::AST::FunctionExpression *fexpr) override;
+
+    bool visit(QQmlJS::AST::FunctionDeclaration *fdecl) override;
+    void endVisit(QQmlJS::AST::FunctionDeclaration *fdecl) override;
+    /* --- end block handling --- */
+
+    bool visit(QQmlJS::AST::VariableDeclarationList *vdl) override;
+    bool visit(QQmlJS::AST::FormalParameterList *fpl) override;
+
+    bool visit(QQmlJS::AST::UiImport *import) override;
+    bool visit(QQmlJS::AST::UiEnumDeclaration *uied) override;
+    bool visit(QQmlJS::AST::UiObjectBinding *uiob) override;
+    void endVisit(QQmlJS::AST::UiObjectBinding *uiob) override;
+    bool visit(QQmlJS::AST::UiObjectDefinition *uiod) override;
+    void endVisit(QQmlJS::AST::UiObjectDefinition *) override;
+    bool visit(QQmlJS::AST::UiScriptBinding *uisb) override;
+    bool visit(QQmlJS::AST::UiPublicMember *uipm) override;
+
+    // expression handling
+    bool visit(QQmlJS::AST::IdentifierExpression *idexp) override;
+};
+
+
+#endif // FINDUNQUALIFIED_H