Search: Dont enable multiline search when regex mode is disabled

BUG: 457146

addons/search/SearchDiskFiles.cpp

@@ -24,7 +24,7 @@ SearchDiskFiles::SearchDiskFiles(SearchDiskFilesWorkList &worklist, const QRegul
 void SearchDiskFiles::run()
 {
     // do we need to search multiple lines?
-    const bool multiLineSearch = m_regExp.pattern().contains(QLatin1String("\\n"));
+    const bool multiLineSearch = m_regExp.patternOptions().testFlag(QRegularExpression::MultilineOption) && m_regExp.pattern().contains(QLatin1String("\\n"));
 
     // timer to emit matchesFound once in a time even for files without matches
     // this triggers process in the UI

addons/search/SearchOpenFiles.cpp

@@ -86,7 +86,7 @@ int SearchOpenFiles::searchOpenFile(KTextEditor::Document *doc, const QRegularEx
         Q_EMIT searching(doc->url().toString());
     }
 
-    if (regExp.pattern().contains(QLatin1String("\\n"))) {
+    if (regExp.patternOptions().testFlag(QRegularExpression::MultilineOption) && regExp.pattern().contains(QLatin1String("\\n"))) {
         return searchMultiLineRegExp(doc, regExp, startLine);
     }
 

addons/search/SearchPlugin.cpp

@@ -987,7 +987,7 @@ void KatePluginSearchView::startSearch()
         patternOptions |= QRegularExpression::CaseInsensitiveOption;
     }
 
-    if (pattern.contains(QLatin1String("\\n"))) {
+    if (m_ui.useRegExp->isChecked() && pattern.contains(QLatin1String("\\n"))) {
         patternOptions |= QRegularExpression::MultilineOption;
     }
     QRegularExpression reg(pattern, patternOptions);
@@ -1166,7 +1166,7 @@ void KatePluginSearchView::startSearchWhileTyping()
     if (!m_ui.matchCase->isChecked()) {
         patternOptions |= QRegularExpression::CaseInsensitiveOption;
     }
-    if (pattern.contains(QLatin1String("\\n"))) {
+    if (m_curResults->useRegExp && pattern.contains(QLatin1String("\\n"))) {
         patternOptions |= QRegularExpression::MultilineOption;
     }
     QRegularExpression reg(pattern, patternOptions);