cmake-gui: Add 'Reload Presets' button, replacing reload timer

Previously the presets handler in the GUI was on a timer.  Because of
this, error messages got suppressed after the first one (even if the
error message is different from the one originally suppressed).

Add a "reload presets" button which forces the preset to reload, and
always provides an error message if the reload failed.

Fixes: #26707

Source/QtDialog/CMakeSetupDialog.cxx

@@ -275,6 +275,8 @@ void CMakeSetupDialog::initialize()
   QObject::connect(this->BrowseSourceDirectoryButton,
                    &QAbstractButton::clicked, this,
                    &CMakeSetupDialog::doSourceBrowse);
+  QObject::connect(this->ReloadPresetsButton, &QAbstractButton::clicked,
+                   this->CMakeThread->cmakeInstance(), &QCMake::loadPresets);
   QObject::connect(this->BrowseBinaryDirectoryButton,
                    &QAbstractButton::clicked, this,
                    &CMakeSetupDialog::doBinaryBrowse);

Source/QtDialog/CMakeSetupDialog.ui

@@ -74,6 +74,13 @@
        </property>
       </widget>
      </item>
+     <item row="1" column="2">
+      <widget class="QPushButton" name="ReloadPresetsButton">
+       <property name="text">
+        <string>Reload &amp;presets</string>
+       </property>
+      </widget>
+     </item>
      <item row="2" column="0">
       <widget class="QLabel" name="BinaryLabel">
        <property name="text">

Source/QtDialog/QCMake.cxx

@@ -64,17 +64,6 @@ QCMake::QCMake(QObject* p)
   for (cmake::GeneratorInfo const& gen : generators) {
     this->AvailableGenerators.push_back(gen);
   }
-
-  connect(&this->LoadPresetsTimer, &QTimer::timeout, this, [this]() {
-    this->loadPresets();
-    if (!this->PresetName.isEmpty() &&
-        this->CMakePresetsGraph.ConfigurePresets.find(
-          std::string(this->PresetName.toStdString())) ==
-          this->CMakePresetsGraph.ConfigurePresets.end()) {
-      this->setPreset(QString{});
-    }
-  });
-  this->LoadPresetsTimer.start(1000);
 }
 
 QCMake::~QCMake() = default;
@@ -572,13 +561,12 @@ void QCMake::loadPresets()
 {
   auto result = this->CMakePresetsGraph.ReadProjectPresets(
     this->SourceDirectory.toStdString(), true);
-  if (result != this->LastLoadPresetsResult && !result) {
+  if (!result) {
     emit this->presetLoadError(
       this->SourceDirectory,
       QString::fromStdString(
         this->CMakePresetsGraph.parseState.GetErrorMessage(false)));
   }
-  this->LastLoadPresetsResult = result;
 
   QVector<QCMakePreset> presets;
   for (auto const& name : this->CMakePresetsGraph.ConfigurePresetOrder) {

Source/QtDialog/QCMake.h

@@ -124,6 +124,8 @@ public slots:
   void setWarnUninitializedMode(bool value);
   /// check if project IDE open is possible and emit openPossible signal
   void checkOpenPossible();
+  /// Reload the preset files and tree
+  void loadPresets();
 
 public:
   /// get the list of cache properties
@@ -193,8 +195,6 @@ protected:
   void stderrCallback(std::string const& msg);
   void setUpEnvironment() const;
 
-  void loadPresets();
-
   bool WarnUninitializedMode;
   QString SourceDirectory;
   QString BinaryDirectory;
@@ -204,11 +204,9 @@ protected:
   QString Toolset;
   std::vector<cmake::GeneratorInfo> AvailableGenerators;
   cmCMakePresetsGraph CMakePresetsGraph;
-  bool LastLoadPresetsResult = true;
   QString PresetName;
   QString CMakeExecutable;
   QAtomicInt InterruptFlag;
   QProcessEnvironment StartEnvironment;
   QProcessEnvironment Environment;
-  QTimer LoadPresetsTimer;
 };

Tests/CMakeGUI/CMakeGUITest.cxx

@@ -359,13 +359,15 @@ void CMakeGUITest::changingPresets()
   QCOMPARE(this->m_window->Preset->isEnabled(), false);
 
   writePresets("build1", { "preset" });
-  loopSleep(1500);
+  this->m_window->ReloadPresetsButton->click();
+  loopSleep();
   QCOMPARE(this->m_window->Preset->presetName(), QString{});
   QCOMPARE(this->m_window->Preset->presets().size(), 1);
   QCOMPARE(this->m_window->BinaryDirectory->currentText(), "");
   QCOMPARE(this->m_window->Preset->isEnabled(), true);
 
   this->m_window->Preset->setPresetName("preset");
+  this->m_window->ReloadPresetsButton->click();
   loopSleep();
   QCOMPARE(this->m_window->Preset->presetName(), "preset");
   QCOMPARE(this->m_window->Preset->presets().size(), 1);
@@ -374,7 +376,8 @@ void CMakeGUITest::changingPresets()
   QCOMPARE(this->m_window->Preset->isEnabled(), true);
 
   writePresets("build2", { "preset2", "preset" });
-  loopSleep(1500);
+  this->m_window->ReloadPresetsButton->click();
+  loopSleep();
   QCOMPARE(this->m_window->Preset->presetName(), "preset");
   QCOMPARE(this->m_window->Preset->presets().size(), 2);
   QCOMPARE(this->m_window->BinaryDirectory->currentText(),
@@ -382,7 +385,8 @@ void CMakeGUITest::changingPresets()
   QCOMPARE(this->m_window->Preset->isEnabled(), true);
 
   writePresets("build3", { "preset2" });
-  loopSleep(1500);
+  this->m_window->ReloadPresetsButton->click();
+  loopSleep();
   QCOMPARE(this->m_window->Preset->presetName(), QString{});
   QCOMPARE(this->m_window->Preset->presets().size(), 1);
   QCOMPARE(this->m_window->BinaryDirectory->currentText(),
@@ -420,7 +424,8 @@ void CMakeGUITest::changingPresets()
 
   QFile(CMakeGUITest_BINARY_DIR "/changingPresets/src2/CMakePresets.json")
     .remove();
-  loopSleep(1500);
+  this->m_window->ReloadPresetsButton->click();
+  loopSleep();
   QCOMPARE(this->m_window->Preset->presetName(), QString{});
   QCOMPARE(this->m_window->Preset->presets().size(), 0);
   QCOMPARE(this->m_window->BinaryDirectory->currentText(),