clangd: make --limit-results configurable in Preferences

The default value is the clangd default value: 100.

Fixes: QTCREATORBUG-27152
Change-Id: Icb6c67645b33325da591cb360c17b3dd55fc60ad
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/clangcodemodel/clangdclient.cpp

@@ -262,8 +262,16 @@ static BaseClientInterface *clientInterface(Project *project, const Utils::FileP
         indexingOption += "=0";
     const QString headerInsertionOption = QString("--header-insertion=")
             + (settings.autoIncludeHeaders() ? "iwyu" : "never");
+
+#ifdef WITH_TESTS
+    // For the #include < test, which needs to get a local header file, but the list
+    // is being flooded with system include headers. 4280 on Windows!
+    const QString limitResults = QString("--limit-results=0");
+#else
+    const QString limitResults = QString("--limit-results=%1").arg(settings.completionResults());
+#endif
     Utils::CommandLine cmd{settings.clangdFilePath(), {indexingOption, headerInsertionOption,
-            "--limit-results=0", "--limit-references=0", "--clang-tidy=0"}};
+            limitResults, "--limit-references=0", "--clang-tidy=0"}};
     if (settings.workerThreadLimit() != 0)
         cmd.addArg("-j=" + QString::number(settings.workerThreadLimit()));
     if (!jsonDbDir.isEmpty())

src/plugins/cppeditor/cppcodemodelsettings.cpp

@@ -83,6 +83,7 @@ static QString clangdUseGlobalSettingsKey() { return QLatin1String("useGlobalSet
 static QString sessionsWithOneClangdKey() { return QLatin1String("SessionsWithOneClangd"); }
 static QString diagnosticConfigIdKey() { return QLatin1String("diagnosticConfigId"); }
 static QString checkedHardwareKey() { return QLatin1String("checkedHardware"); }
+static QString completionResultsKey() { return QLatin1String("completionResults"); }
 
 static FilePath g_defaultClangdFilePath;
 static FilePath fallbackClangdFilePath()
@@ -489,6 +490,7 @@ QVariantMap ClangdSettings::Data::toMap() const
     map.insert(sessionsWithOneClangdKey(), sessionsWithOneClangd);
     map.insert(diagnosticConfigIdKey(), diagnosticConfigId.toSetting());
     map.insert(checkedHardwareKey(), true);
+    map.insert(completionResultsKey(), completionResults);
     return map;
 }
 
@@ -506,6 +508,7 @@ void ClangdSettings::Data::fromMap(const QVariantMap &map)
     diagnosticConfigId = Id::fromSetting(map.value(diagnosticConfigIdKey(),
                                                    initialClangDiagnosticConfigId().toSetting()));
     haveCheckedHardwareReqirements = map.value(checkedHardwareKey(), false).toBool();
+    completionResults = map.value(completionResultsKey(), kDefaultCompletionResults).toInt();
 }
 
 } // namespace CppEditor

src/plugins/cppeditor/cppcodemodelsettings.h

@@ -93,6 +93,9 @@ class CPPEDITOR_EXPORT ClangdSettings : public QObject
 {
     Q_OBJECT
 public:
+    // Default clangd --limit-results value is 100
+    static const int kDefaultCompletionResults = 100;
+
     class CPPEDITOR_EXPORT Data
     {
     public:
@@ -112,7 +115,8 @@ public:
                     && s1.documentUpdateThreshold == s2.documentUpdateThreshold
                     && s1.sizeThresholdEnabled == s2.sizeThresholdEnabled
                     && s1.sizeThresholdInKb == s2.sizeThresholdInKb
-                    && s1.haveCheckedHardwareReqirements == s2.haveCheckedHardwareReqirements;
+                    && s1.haveCheckedHardwareReqirements == s2.haveCheckedHardwareReqirements
+                    && s1.completionResults == s2.completionResults;
         }
         friend bool operator!=(const Data &s1, const Data &s2) { return !(s1 == s2); }
 
@@ -128,6 +132,7 @@ public:
         bool autoIncludeHeaders = false;
         bool sizeThresholdEnabled = false;
         bool haveCheckedHardwareReqirements = false;
+        int completionResults = kDefaultCompletionResults;
     };
 
     ClangdSettings(const Data &data) : m_data(data) {}
@@ -148,6 +153,7 @@ public:
     int documentUpdateThreshold() const { return m_data.documentUpdateThreshold; }
     qint64 sizeThresholdInKb() const { return m_data.sizeThresholdInKb; }
     bool sizeThresholdEnabled() const { return m_data.sizeThresholdEnabled; }
+    int completionResults() const { return m_data.completionResults; }
     bool sizeIsOkay(const Utils::FilePath &fp) const;
     ClangDiagnosticConfigs customDiagnosticConfigs() const;
     Utils::Id diagnosticConfigId() const;

src/plugins/cppeditor/cppcodemodelsettingspage.cpp

@@ -178,6 +178,7 @@ public:
     QSpinBox threadLimitSpinBox;
     QSpinBox documentUpdateThreshold;
     QSpinBox sizeThresholdSpinBox;
+    QSpinBox completionResults;
     Utils::PathChooser clangdChooser;
     Utils::InfoLabel versionWarningLabel;
     ClangDiagnosticConfigsSelectionWidget *configSelectionWidget = nullptr;
@@ -224,6 +225,13 @@ ClangdSettingsWidget::ClangdSettingsWidget(const ClangdSettings::Data &settingsD
             "Files greater than this will not be opened as documents in clangd.\n"
             "The built-in code model will handle highlighting, completion and so on."));
 
+    const auto completionResultsLabel = new QLabel(tr("Completion results:"));
+    d->completionResults.setMinimum(0);
+    d->completionResults.setMaximum(std::numeric_limits<int>::max());
+    d->completionResults.setValue(settings.completionResults());
+    d->completionResults.setToolTip(tr("The maximum number of completion results returned by clangd"));
+    d->completionResults.setSpecialValueText(tr("No limit"));
+
     const auto layout = new QVBoxLayout(this);
     layout->setContentsMargins(0, 0, 0, 0);
     layout->addWidget(&d->useClangdCheckBox);
@@ -245,6 +253,12 @@ ClangdSettingsWidget::ClangdSettingsWidget(const ClangdSettings::Data &settingsD
     documentUpdateThresholdLayout->addStretch(1);
     const auto documentUpdateThresholdLabel = new QLabel(tr("Document update threshold:"));
     formLayout->addRow(documentUpdateThresholdLabel, documentUpdateThresholdLayout);
+
+    const auto limitResultsLayout = new QHBoxLayout;
+    limitResultsLayout->addWidget(&d->completionResults);
+    limitResultsLayout->addStretch(1);
+    formLayout->addRow(completionResultsLabel, limitResultsLayout);
+
     const auto sizeThresholdLayout = new QHBoxLayout;
     sizeThresholdLayout->addWidget(&d->sizeThresholdSpinBox);
     sizeThresholdLayout->addStretch(1);