logic: don't allow partial re-indexing for python source groups

src/lib_python/project/SourceGroupPythonEmpty.cpp

@@ -13,6 +13,11 @@ SourceGroupPythonEmpty::SourceGroupPythonEmpty(std::shared_ptr<SourceGroupSettin
 {
 }
 
+bool SourceGroupPythonEmpty::allowsPartialClearing() const
+{
+	return false;
+}
+
 std::set<FilePath> SourceGroupPythonEmpty::filterToContainedFilePaths(const std::set<FilePath>& filePaths) const
 {
 	return SourceGroup::filterToContainedFilePaths(

src/lib_python/project/SourceGroupPythonEmpty.h

@@ -13,6 +13,7 @@ class SourceGroupPythonEmpty: public SourceGroup
 public:
 	SourceGroupPythonEmpty(std::shared_ptr<SourceGroupSettingsPythonEmpty> settings);
 
+	bool allowsPartialClearing() const override;
 	std::set<FilePath> filterToContainedFilePaths(const std::set<FilePath>& filePaths) const override;
 	std::set<FilePath> getAllSourceFilePaths() const override;
 	std::vector<std::shared_ptr<IndexerCommand>> getIndexerCommands(const std::set<FilePath>& filesToIndex) const override;