Bug fix: Crash when an application is stopped

Added a new class ButtonWidget that contains the QPushButton that was
before part of the CocoBuildStep class. The change was necessary
because now the button can be destroyed and recreated by Qt
Creator (via CocoBuildStep::createConfigWidget()) wihout creating
dangling pointers or other memory problems.

Fixes: QTCREATORBUG-32045
Change-Id: I4789160cf3d9ef0d286d0456eeb15304cd297677
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/coco/cocobuildstep.cpp

@@ -8,15 +8,11 @@
 #include "cocotr.h"
 
 #include <cmakeprojectmanager/cmakeprojectconstants.h>
-
 #include <projectexplorer/projectexplorerconstants.h>
 #include <projectexplorer/projectmanager.h>
 #include <projectexplorer/target.h>
-
 #include <qmakeprojectmanager/qmakeprojectmanagerconstants.h>
-
 #include <solutions/tasking/tasktree.h>
-
 #include <utils/layoutbuilder.h>
 
 #include <QPushButton>
@@ -25,6 +21,39 @@ namespace Coco::Internal {
 
 using namespace ProjectExplorer;
 
+class ButtonWidget : public QWidget
+// The configuration button of the CocoBuildstep must be part of a separated object
+// because it may be several times recreated by createConfigWidget().
+{
+public:
+    explicit ButtonWidget(CocoBuildStep *step);
+
+private slots:
+    void setButtonState(bool enabled, const QString &text);
+
+private:
+    QPushButton *m_button;
+};
+
+ButtonWidget::ButtonWidget(CocoBuildStep *step)
+    : m_button{new QPushButton}
+{
+    connect(m_button, &QPushButton::clicked, step, &CocoBuildStep::onButtonClicked);
+    connect(step, &CocoBuildStep::setButtonState, this, &ButtonWidget::setButtonState);
+
+    Layouting::Form builder;
+    builder.addRow({m_button, new QLabel});
+    builder.setNoMargins();
+    builder.attachTo(this);
+}
+
+void ButtonWidget::setButtonState(bool enabled, const QString &text)
+{
+    m_button->setEnabled(enabled);
+    if (!text.isEmpty())
+        m_button->setText(text);
+}
+
 CocoBuildStep *CocoBuildStep::create(BuildConfiguration *buildConfig)
 {
     // The "new" command creates a small memory leak which we can tolerate.
@@ -34,7 +63,6 @@ CocoBuildStep *CocoBuildStep::create(BuildConfiguration *buildConfig)
 
 CocoBuildStep::CocoBuildStep(ProjectExplorer::BuildStepList *bsl, Utils::Id id)
     : BuildStep(bsl, id)
-    , m_reconfigureButton{new QPushButton}
 {}
 
 bool CocoBuildStep::init()
@@ -47,12 +75,13 @@ void CocoBuildStep::buildSystemUpdated()
     updateDisplay();
 }
 
-void CocoBuildStep::onReconfigureButtonClicked()
+void CocoBuildStep::onButtonClicked()
 {
     m_valid = !m_valid;
 
     setSummaryText(Tr::tr("Coco Code Coverage: Reconfiguring..."));
-    m_reconfigureButton->setEnabled(false);
+    emit setButtonState(false);
+
     m_buildSettings->setCoverage(m_valid);
     m_buildSettings->provideFile();
     m_buildSettings->reconfigure();
@@ -60,17 +89,10 @@ void CocoBuildStep::onReconfigureButtonClicked()
 
 QWidget *CocoBuildStep::createConfigWidget()
 {
-    connect(
-        m_reconfigureButton,
-        &QPushButton::clicked,
-        this,
-        &CocoBuildStep::onReconfigureButtonClicked);
+    auto widget = new ButtonWidget{this};
+    updateDisplay();
 
-    Layouting::Form builder;
-    builder.addRow({m_reconfigureButton, new QLabel});
-    builder.setNoMargins();
-
-    return builder.emerge();
+    return widget;
 }
 
 void CocoBuildStep::updateDisplay()
@@ -78,7 +100,7 @@ void CocoBuildStep::updateDisplay()
     CocoInstallation coco;
     if (!coco.isValid()) {
         setSummaryText("<i>" + Tr::tr("Coco Code Coverage: No working Coco installation") + "</i>");
-        m_reconfigureButton->setEnabled(false);
+        emit setButtonState(false);
         return;
     }
 
@@ -86,13 +108,12 @@ void CocoBuildStep::updateDisplay()
 
     if (m_valid) {
         setSummaryText("<b>" + Tr::tr("Coco Code Coverage: Enabled") + "</b>");
-        m_reconfigureButton->setText(Tr::tr("Disable Coverage"));
+        emit setButtonState(true, Tr::tr("Disable Coverage"));
     } else {
         setSummaryText(Tr::tr("Coco Code Coverage: Disabled"));
-        m_reconfigureButton->setText(Tr::tr("Enable Coverage"));
+        // m_reconfigureButton->setText(Tr::tr("Enable Coverage"));
+        emit setButtonState(true, Tr::tr("Enable Coverage"));
     }
-
-    m_reconfigureButton->setEnabled(true);
 }
 
 void CocoBuildStep::display(BuildConfiguration *buildConfig)
@@ -157,7 +178,7 @@ void setupCocoBuildSteps()
     static QMakeStepFactory theQmakeStepFactory;
     static CMakeStepFactory theCmakeStepFactory;
 
-    QObject::connect(ProjectManager::instance(), &ProjectManager::projectAdded, [&](Project *project) {
+    QObject::connect(ProjectManager::instance(), &ProjectManager::projectAdded, [](Project *project) {
         if (Target *target = project->activeTarget())
             addBuildStep(target);
 

src/plugins/coco/cocobuildstep.h

@@ -18,6 +18,7 @@ namespace Coco::Internal {
 class CocoBuildStep : public ProjectExplorer::BuildStep
 {
     Q_OBJECT
+
 public:
     static CocoBuildStep *create(ProjectExplorer::BuildConfiguration *buildConfig);
 
@@ -26,11 +27,12 @@ public:
     bool init() override;
     void display(ProjectExplorer::BuildConfiguration *buildConfig);
 
+signals:
+    void setButtonState(bool enabled, const QString &text = {});
+
 public slots:
     void buildSystemUpdated();
-
-private slots:
-    void onReconfigureButtonClicked();
+    void onButtonClicked();
 
 protected:
     QWidget *createConfigWidget() override;
@@ -41,7 +43,6 @@ private:
 
     QPointer<BuildSettings> m_buildSettings;
     bool m_valid;
-    QPushButton *m_reconfigureButton;
 };
 
 void setupCocoBuildSteps();