Merge master into fix/joined-wire-uuid

The conflict was tests/qttest/CMakeLists.txt, where #1520 added
tst_savedstamps at the place this branch adds tst_joinedwireuuid. Both
are kept.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

sources/dataBase/projectdatabase.cpp

@@ -847,13 +847,15 @@ bool projectDataBase::populateFromDocument(const QDomDocument &document, QString
 		}
 	}
 
-	query.prepare(QStringLiteral("INSERT INTO link (element_uuid, linked_uuid, group_index) "
-								 "VALUES (:element_uuid, :linked_uuid, :group_index)"));
+	query.prepare(QStringLiteral("INSERT INTO link (element_uuid, linked_uuid, group_index, ord) "
+								 "VALUES (:element_uuid, :linked_uuid, :group_index, :ord)"));
 	for (const DocumentElement &element : std::as_const(elements)) {
+		int ord = 0;
 		for (const auto &link : element.links) {
 			query.bindValue(QStringLiteral(":element_uuid"), element.uuid);
 			query.bindValue(QStringLiteral(":linked_uuid"), link.first);
 			query.bindValue(QStringLiteral(":group_index"), link.second >= 0 ? QVariant(link.second) : QVariant());
+			query.bindValue(QStringLiteral(":ord"), ord++);
 			if (!query.exec()) {
 				qDebug() << "projectDataBase::populateFromDocument link insert error : " << query.lastError();
 			}
@@ -1092,7 +1094,7 @@ QList<QUuid> projectDataBase::linkedSymbols(const QUuid &element) const
 {
 	QList<QUuid> linked;
 	QSqlQuery query(m_data_base);
-	query.prepare(QStringLiteral("SELECT linked_uuid FROM link WHERE element_uuid = :uuid ORDER BY rowid"));
+	query.prepare(QStringLiteral("SELECT linked_uuid FROM link WHERE element_uuid = :uuid ORDER BY ord, rowid"));
 	query.bindValue(QStringLiteral(":uuid"), element.toString());
 	if (query.exec()) {
 		while (query.next())
@@ -2602,12 +2604,14 @@ bool projectDataBase::createDataBase()
 
 		//Create the link table: one row per element and element it is
 		//linked to -- a coil and its contacts, a pair of folio reports --
-		//from each side, with the contact group the element saved for it.
+		//from each side, with the contact group the element saved for it,
+		//and its place (ord) in the order the element saves its links.
 	const QString link_table(QStringLiteral(
 			"CREATE TABLE link ("
 			"element_uuid VARCHAR(50) NOT NULL, "
 			"linked_uuid VARCHAR(50) NOT NULL, "
 			"group_index INTEGER, "
+			"ord INTEGER NOT NULL DEFAULT 0, "
 			"PRIMARY KEY (element_uuid, linked_uuid), "
 			"FOREIGN KEY (element_uuid) REFERENCES element (uuid))"));
 	if (!query_.exec(link_table)) {
@@ -3868,10 +3872,11 @@ QString projectDataBase::prefillReport() const
 void projectDataBase::populateLinkTable()
 {
 	m_dirty_link_elements.clear();
+	const QSet<QUuid> waiting = waitingSymbols();
 	QSqlQuery query(m_data_base);
 	query.exec(QStringLiteral("DELETE FROM link"));
-	query.prepare(QStringLiteral("INSERT INTO link (element_uuid, linked_uuid, group_index) "
-								 "VALUES (:element_uuid, :linked_uuid, :group_index)"));
+	query.prepare(QStringLiteral("INSERT INTO link (element_uuid, linked_uuid, group_index, ord) "
+								 "VALUES (:element_uuid, :linked_uuid, :group_index, :ord)"));
 
 	for (const auto &diagram : m_project->folios())
 	{
@@ -3885,23 +3890,7 @@ void projectDataBase::populateLinkTable()
 		}
 		const ElementProvider ep(diagram);
 		for (const auto &elmt : ep.find(allElementTypes()))
-		{
-			QList<std::pair<QString, int>> rows;
-			for (Element *linked : elmt->linkedElements())
-				rows.append({linked->uuid().toString(), elmt->groupIndexForElement(linked)});
-				//Partners on a folio not built, which it will be linked to
-			for (const auto &waiting : elmt->waitingLinks())
-				rows.append({waiting.first.toString(), waiting.second});
-			for (const auto &row : std::as_const(rows))
-			{
-				query.bindValue(QStringLiteral(":element_uuid"), elmt->uuid().toString());
-				query.bindValue(QStringLiteral(":linked_uuid"), row.first);
-				query.bindValue(QStringLiteral(":group_index"), row.second >= 0 ? QVariant(row.second) : QVariant());
-				if (!query.exec()) {
-					qDebug() << "projectDataBase::populateLinkTable insert error : " << query.lastError();
-				}
-			}
-		}
+			insertLinkRows(query, elmt, waiting);
 	}
 }
 
@@ -3927,6 +3916,83 @@ void projectDataBase::queueLinks(Element *element)
 	}
 }
 
+/**
+	@brief projectDataBase::linkRowMismatches
+	A test and debugging aid (QET_CHECK_LINK_ROWS): the placed
+	symbols whose link rows are not the links they save, in order
+	(Element::linksToSave(), insertLinkRows())
+	@return one entry per such symbol: its uuid
+*/
+QStringList projectDataBase::linkRowMismatches()
+{
+	flushLinks();
+	const QSet<QUuid> waiting = waitingSymbols();
+	QStringList mismatches;
+	QSqlQuery query(m_data_base);
+	query.prepare(QStringLiteral("SELECT linked_uuid, group_index FROM link "
+								 "WHERE element_uuid = :uuid ORDER BY ord, rowid"));
+	for (auto it = m_placed_elements.cbegin() ; it != m_placed_elements.cend() ; ++it)
+	{
+		Element *element = it.value();
+		if (!element) {
+			continue;
+		}
+		QList<std::pair<QString, int>> expected;
+		for (const Element::SavedLink &link : element->linksToSave(waiting))
+			if (!link.built || m_placed_elements.contains(link.uuid, link.built))
+				expected.append({link.uuid.toString(), link.group_index});
+		QList<std::pair<QString, int>> rows;
+		query.bindValue(QStringLiteral(":uuid"), element->uuid().toString());
+		if (query.exec())
+			while (query.next())
+				rows.append({query.value(0).toString(),
+							 query.value(1).isNull() ? -1 : query.value(1).toInt()});
+		if (rows != expected) {
+			mismatches << element->uuid().toString();
+		}
+	}
+	return mismatches;
+}
+
+/**
+	@brief projectDataBase::waitingSymbols
+	@return the symbols on folios not built yet (lazy folios): partners a
+	symbol keeps its saved links to until they are built
+*/
+QSet<QUuid> projectDataBase::waitingSymbols() const
+{
+	return m_project && m_project->unloadedFolioCount() ? m_project->symbolsOnUnbuiltFolios()
+														: QSet<QUuid>();
+}
+
+/**
+	@brief projectDataBase::insertLinkRows
+	Write @p element's link rows with @p insert (prepared with :element_uuid,
+	:linked_uuid, :group_index and :ord): its partners as it saves them
+	(Element::linksToSave()), in that order, so the rows and the file say
+	the same: @p waiting is the symbols on folios not built, as a save
+	takes them (waitingSymbols()). A built partner the project no longer has (on a removed
+	folio, linked still for the undo) gets no row.
+*/
+void projectDataBase::insertLinkRows(QSqlQuery &insert, Element *element,
+									 const QSet<QUuid> &waiting)
+{
+	int ord = 0;
+	for (const Element::SavedLink &link : element->linksToSave(waiting))
+	{
+		if (link.built && !m_placed_elements.contains(link.uuid, link.built)) {
+			continue;
+		}
+		insert.bindValue(QStringLiteral(":element_uuid"), element->uuid().toString());
+		insert.bindValue(QStringLiteral(":linked_uuid"), link.uuid.toString());
+		insert.bindValue(QStringLiteral(":group_index"), link.group_index >= 0 ? QVariant(link.group_index) : QVariant());
+		insert.bindValue(QStringLiteral(":ord"), ord++);
+		if (!insert.exec()) {
+			qDebug() << "projectDataBase::insertLinkRows insert error : " << insert.lastError();
+		}
+	}
+}
+
 /**
 	@brief projectDataBase::flushLinks
 	Write the link rows of every element queued by linksChanged()
@@ -3939,12 +4005,13 @@ void projectDataBase::flushLinks()
 
 	const auto dirty = m_dirty_link_elements;
 	m_dirty_link_elements.clear();
+	const QSet<QUuid> waiting = waitingSymbols();
 	const bool own_transaction = m_data_base.transaction();
 	QSqlQuery remove(m_data_base);
 	remove.prepare(QStringLiteral("DELETE FROM link WHERE element_uuid = :uuid"));
 	QSqlQuery insert(m_data_base);
-	insert.prepare(QStringLiteral("INSERT INTO link (element_uuid, linked_uuid, group_index) "
-								  "VALUES (:element_uuid, :linked_uuid, :group_index)"));
+	insert.prepare(QStringLiteral("INSERT INTO link (element_uuid, linked_uuid, group_index, ord) "
+								  "VALUES (:element_uuid, :linked_uuid, :group_index, :ord)"));
 	for (const QPointer<Element> &element : dirty)
 	{
 		if (!element) {
@@ -3960,32 +4027,7 @@ void projectDataBase::flushLinks()
 		if (!m_placed_elements.contains(element->uuid(), element)) {
 			continue;
 		}
-		for (Element *linked : element->linkedElements())
-		{
-				//A symbol on a removed folio stays linked, for the undo,
-				//but the project no longer has it
-			if (!m_placed_elements.contains(linked->uuid(), linked)) {
-				continue;
-			}
-			const int group = element->groupIndexForElement(linked);
-			insert.bindValue(QStringLiteral(":element_uuid"), element->uuid().toString());
-			insert.bindValue(QStringLiteral(":linked_uuid"), linked->uuid().toString());
-			insert.bindValue(QStringLiteral(":group_index"), group >= 0 ? QVariant(group) : QVariant());
-			if (!insert.exec()) {
-				qDebug() << "projectDataBase::flushLinks insert error : " << insert.lastError();
-			}
-		}
-			//Partners on a folio not built (lazy folios), which it will
-			//be linked to once that folio is
-		for (const auto &waiting : element->waitingLinks())
-		{
-			insert.bindValue(QStringLiteral(":element_uuid"), element->uuid().toString());
-			insert.bindValue(QStringLiteral(":linked_uuid"), waiting.first.toString());
-			insert.bindValue(QStringLiteral(":group_index"), waiting.second >= 0 ? QVariant(waiting.second) : QVariant());
-			if (!insert.exec()) {
-				qDebug() << "projectDataBase::flushLinks insert error : " << insert.lastError();
-			}
-		}
+		insertLinkRows(insert, element, waiting);
 	}
 	if (own_transaction) {
 		m_data_base.commit();

sources/dataBase/projectdatabase.h

@@ -154,6 +154,7 @@ class projectDataBase : public QObject
 		void conductorPropertiesStored(Conductor *conductor, const ConductorProperties &properties);
 		void conductorUuidChanged(Conductor *conductor, const QUuid &old_uuid);
 		QStringList conductorPropertiesMismatches() const;
+		QStringList linkRowMismatches();
 
 			//Fill the three stores from a project's document before its
 			//folios are built, then, once
@@ -253,6 +254,8 @@ class projectDataBase : public QObject
 		void populateConductorTable();
 		void populateLinkTable();
 		void flushLinks();
+		void insertLinkRows(QSqlQuery &insert, Element *element, const QSet<QUuid> &waiting);
+		QSet<QUuid> waitingSymbols() const;
 		void populateDrawingItemTables();
 		bool populateFromDocument(const QDomDocument &document, QString *why = nullptr);
 		bool writeDrawingItem(QObject *object);

sources/diagram.cpp

@@ -2342,6 +2342,23 @@ bool Diagram::fromXml(QDomElement &document,
 						  << "wire end(s) on a terminal that moved since the project was saved,"
 						  << "matched to it by place";
 	}
+		//A copy of a symbol sharing its uuid with another (older versions'
+		//copies, F100) gets its own, now that its wires are connected to
+		//it: wires and links then name one symbol each
+		//(QETProject::renewedSharedUuid(), only while the project opens)
+	if (consider_informations && m_project) {
+		const int folio_index = m_project->folioIndex(this);
+		QHash<QUuid, int> ordinal;
+		for (Element *element : std::as_const(added_elements)) {
+			const QUuid shared = element->uuid();
+			const QUuid renewed = m_project->renewedSharedUuid(folio_index, ordinal[shared]++,
+															   shared, uuid());
+			if (!renewed.isNull()) {
+				element->setUuid(renewed);
+			}
+		}
+	}
+
 	if (consider_informations && !m_wires_not_reconnected.isEmpty()) {
 		qWarning().noquote() << "Diagram::fromXml():"
 							 << m_wires_not_reconnected.size()

sources/qetgraphicsitem/element.cpp

@@ -1437,32 +1437,11 @@ QDomElement Element::toXml(
 	element.appendChild(inputs);
 
 	//if this element is linked to other elements,
-	//save the uuid of each other elements
-		//A partner on a folio not built yet (lazy folios), which this
-		//symbol will be linked to, is saved too, in the order the symbol was
-		//saved with: saving needs no partner built (stage D5a)
+	//save the uuid of each other elements (linksToSave())
 	QList<std::pair<QUuid, int>> links;
-	if (keepsSavedLinks() && diagram() && diagram()->project()) {
-		const QSet<QUuid> waiting = diagram()->project()->waitingLinkTargets();
-		QSet<Element *> written;
-		for (const auto &link_info : std::as_const(tmp_uuids_link)) {
-			Element *linked = nullptr;
-			for (Element *elmt : std::as_const(connected_elements))
-				if (elmt->uuid() == link_info.uuid && !written.contains(elmt)) { linked = elmt; break; }
-			if (linked) {
-				written.insert(linked);
-				links.append({linked->uuid(), m_group_index_map.value(linked, -1)});
-			} else if (waiting.contains(link_info.uuid)) {
-				links.append({link_info.uuid, link_info.group_index});
-			}
-		}
-		for (Element *elmt : std::as_const(connected_elements))
-			if (!written.contains(elmt))
-				links.append({elmt->uuid(), m_group_index_map.value(elmt, -1)});
-	} else {
-		for (Element *elmt : std::as_const(connected_elements))
-			links.append({elmt->uuid(), m_group_index_map.value(elmt, -1)});
-	}
+	for (const SavedLink &link : linksToSave(diagram() && diagram()->project()
+											 ? diagram()->project()->waitingLinkTargets() : QSet<QUuid>()))
+		links.append({link.uuid, link.group_index});
 	if (!links.isEmpty()) {
 		QDomElement links_uuids = document.createElement(QStringLiteral("links_uuids"));
 		for (const auto &link : std::as_const(links)) {
@@ -1869,6 +1848,45 @@ void Element::initLink(QETProject *prj)
 	}
 }
 
+/**
+	@brief Element::linksToSave
+	The partners this symbol saves, in the order it saves them: the order
+	it was saved with (tmp_uuids_link), then partners linked since. A
+	partner on a folio not built yet (lazy folios), which this symbol will
+	be linked to, is in the list too: saving needs no partner built (stage
+	D5a). toXml() writes this list, and the project database's link rows
+	are written from it, so the two are the same (QETZ-DB-FIRST stage 2a).
+	@param waiting the symbols on folios not built: a saved partner among
+	them is kept (QETProject::symbolsOnUnbuiltFolios())
+	@return each partner's uuid, its contact group (-1 if none), and the
+	partner itself when it is built (nullptr for one waiting)
+*/
+QList<Element::SavedLink> Element::linksToSave(const QSet<QUuid> &waiting) const
+{
+	QList<SavedLink> links;
+	if (keepsSavedLinks() && diagram() && diagram()->project()) {
+		QSet<Element *> written;
+		for (const auto &link_info : std::as_const(tmp_uuids_link)) {
+			Element *linked = nullptr;
+			for (Element *elmt : std::as_const(connected_elements))
+				if (elmt->uuid() == link_info.uuid && !written.contains(elmt)) { linked = elmt; break; }
+			if (linked) {
+				written.insert(linked);
+				links.append({linked->uuid(), m_group_index_map.value(linked, -1), linked});
+			} else if (waiting.contains(link_info.uuid)) {
+				links.append({link_info.uuid, link_info.group_index, nullptr});
+			}
+		}
+		for (Element *elmt : std::as_const(connected_elements))
+			if (!written.contains(elmt))
+				links.append({elmt->uuid(), m_group_index_map.value(elmt, -1), elmt});
+	} else {
+		for (Element *elmt : std::as_const(connected_elements))
+			links.append({elmt->uuid(), m_group_index_map.value(elmt, -1), elmt});
+	}
+	return links;
+}
+
 /**
 	@brief Element::pendingLinks
 	@return the uuids of the partners this symbol was saved linked to and

sources/qetgraphicsitem/element.h

@@ -227,6 +227,13 @@ class Element : public QetGraphicsItem
 		virtual void unlinkElement(Element *) {}
 		virtual void initLink(QETProject *);
 		QSet<QUuid> pendingLinks() const;
+			/// A partner as the symbol saves it (linksToSave())
+		struct SavedLink {
+			QUuid uuid;
+			int group_index = -1;
+			Element *built = nullptr;   ///< nullptr: on a folio not built yet
+		};
+		QList<SavedLink> linksToSave(const QSet<QUuid> &waiting) const;
 		bool keepsSavedLinks() const {return !tmp_uuids_link.isEmpty();}
 		QList<std::pair<QUuid, int>> waitingLinks() const;
 			/**

sources/qetproject.cpp

@@ -299,6 +299,27 @@ QByteArray QETProject::containerPicture(const QString &file) const
 	return m_container_pictures.value(file);
 }
 
+/**
+	@brief QETProject::renewedSharedUuid
+	While the project opens: the uuid of the @p ordinal -th symbol carrying
+	@p uuid on the folio at @p folio_index (in the file's order), when
+	other symbols of the project carry the same uuid and this copy is not
+	the one keeping it (readDiagramsXml()). Derived from the uuid and the
+	folio's uuid, so the same file gives the same uuid on every open.
+	@return a null uuid when this symbol keeps its uuid
+*/
+QUuid QETProject::renewedSharedUuid(int folio_index, int ordinal, const QUuid &uuid,
+									const QUuid &folio_uuid)
+{
+	const auto keeper = m_shared_uuid_keepers.constFind(uuid);
+	if (keeper == m_shared_uuid_keepers.constEnd()
+			|| (keeper->first == folio_index && keeper->second == ordinal)) {
+		return QUuid();
+	}
+	return derivedItemUuid(QStringLiteral("element-copy"),
+						   uuid.toString() + QLatin1Char('\n') + folio_uuid.toString());
+}
+
 /**
 	@brief QETProject::derivedItemUuid
 	A uuid for an item of this project that was saved without one, the same
@@ -474,6 +495,8 @@ QETProject::ProjectState QETProject::openFile(QFile *file)
 	}
 	QFileInfo fi(*file);
 	setFilePath(fi.absoluteFilePath());
+		//Saved again unchanged, the file keeps its saved date and path
+	m_stamped_path = m_file_path;
 
 		//Extract the content of the xml. The raw bytes are kept : a project
 		//file without a persisted uuid derives its uuid from them.
@@ -1161,16 +1184,8 @@ void QETProject::setFilePath(const QString &filepath)
 		setReadOnly(false);
 	}
 
-		//title block variables should be updated after file save as dialog is confirmed, before file is saved.
-	m_project_properties.addValue("saveddate",     QLocale::system().toString(QDate::currentDate(), QLocale::ShortFormat));
-	m_project_properties.addValue("saveddate-eu",  QDate::currentDate().toString("dd-MM-yyyy"));
-	m_project_properties.addValue("saveddate-us",  QDate::currentDate().toString("yyyy-MM-dd"));
-	m_project_properties.addValue("savedtime",     QDateTime::currentDateTime().toString("HH:mm"));
-	m_project_properties.addValue("savedfilename", QFileInfo(filePath()).completeBaseName());
-	m_project_properties.addValue("savedfilepath", filePath());
-
-
-
+		//The saved date, time and path of the title block are set by
+		//write(), when the project is saved (stampSaved())
 	emit projectFilePathChanged(this, m_file_path);
 	emit projectInformationsChanged(this);
 	updateDiagramsFolioData();
@@ -2636,6 +2651,16 @@ QDomDocument QETProject::toXml(QHash<int, QByteArray> *kept_folios, QStringList
 	// Write the elements collection.
 	project_root.appendChild(m_elements_collection->root().cloneNode(true));
 
+		//QET_CHECK_LINK_ROWS=1: say whether the project database's link rows
+		//are the links each placed symbol saves, in its order, once the
+		//folios are written. Builds nothing (lazy folios stay as they are):
+		//a test and debugging aid; it changes nothing.
+	if (qEnvironmentVariableIntValue("QET_CHECK_LINK_ROWS") == 1) {
+		const QStringList links = m_data_base.linkRowMismatches();
+		qWarning().noquote() << "link rows:" << links.size() << "differ"
+							 << links.mid(0, 5).join(QStringLiteral(", "));
+	}
+
 	m_waiting_link_targets.clear();
 	return(xml_doc);
 }
@@ -2801,6 +2826,33 @@ bool QETProject::changedOnDisk(QDateTime *when) const
 	return true;
 }
 
+/**
+	@brief QETProject::stampSaved
+	Set the title block variables of the save (saveddate, saveddate-eu,
+	saveddate-us, savedtime, savedfilename, savedfilepath) to now and to
+	the file being written, when there is something new to save: the
+	project changed since it was opened or last saved, or it is written to
+	another file. Otherwise they keep what the file holds, so saving an
+	unchanged project gives an identical file (F124).
+	@return true if they were set
+*/
+bool QETProject::stampSaved()
+{
+	const bool changed = m_modified || m_undo_stack->index() != m_stamped_undo_index;
+	if (!changed && m_file_path == m_stamped_path) {
+		return false;
+	}
+	m_project_properties.addValue("saveddate",     QLocale::system().toString(QDate::currentDate(), QLocale::ShortFormat));
+	m_project_properties.addValue("saveddate-eu",  QDate::currentDate().toString("dd-MM-yyyy"));
+	m_project_properties.addValue("saveddate-us",  QDate::currentDate().toString("yyyy-MM-dd"));
+	m_project_properties.addValue("savedtime",     QDateTime::currentDateTime().toString("HH:mm"));
+	m_project_properties.addValue("savedfilename", QFileInfo(filePath()).completeBaseName());
+	m_project_properties.addValue("savedfilepath", filePath());
+	emit projectInformationsChanged(this);
+	updateDiagramsFolioData();
+	return true;
+}
+
 /**
 	@brief QETProject::write
 	Save the project in a file.
@@ -2868,13 +2920,28 @@ QETResult QETProject::write(bool overwrite_changed)
 	if (!PreviousVersions::keep(m_file_path, PreviousVersions::count(), &backup_error))
 		qWarning().noquote() << "Previous version of" << m_file_path << "not kept:" << backup_error;
 
+		//The saved date, time and path go into the file being written, and
+		//only when there is something new to save: an unchanged project
+		//saves to an identical file (F124, a project kept in git). A
+		//failed write puts the previous values back.
+	const DiagramContext stamped_before = m_project_properties;
+	const bool stamped = stampSaved();
+	const auto failed_stamped = [&](const QString &error) {
+		if (stamped) {
+			m_project_properties = stamped_before;
+			emit projectInformationsChanged(this);
+			updateDiagramsFolioData();
+		}
+		return failed(error);
+	};
+
 	QString error_message;
 	if (isContainerPath(m_file_path))
 	{
 			//A container is written from the whole document: every folio
 			//built (stage D4 writes it from the database)
 		if (!writeContainerFile(m_file_path, &error_message))
-			return(failed(error_message));
+			return(failed_stamped(error_message));
 	}
 	else
 	{
@@ -2884,7 +2951,7 @@ QETResult QETProject::write(bool overwrite_changed)
 		QDomDocument xml_project(toXml(&kept_folios));
 		if (!QET::writeXmlText(spliceKeptFolios(xml_project.toString(4), kept_folios),
 						   m_file_path, &error_message))
-			return(failed(error_message));
+			return(failed_stamped(error_message));
 	}
 
 	rememberDiskState();
@@ -2905,17 +2972,8 @@ QETResult QETProject::write(bool overwrite_changed)
 		}
 	}
 
-		//title block variables should be updated after file save dialog is confirmed, before file is saved.
-	m_project_properties.addValue("saveddate",     QLocale::system().toString(QDate::currentDate(), QLocale::ShortFormat));
-	m_project_properties.addValue("saveddate-us",  QDate::currentDate().toString("yyyy-MM-dd"));
-	m_project_properties.addValue("saveddate-eu",  QDate::currentDate().toString("dd-MM-yyyy"));
-	m_project_properties.addValue("savedtime",     QDateTime::currentDateTime().toString("HH:mm"));
-	m_project_properties.addValue("savedfilename", QFileInfo(filePath()).completeBaseName());
-	m_project_properties.addValue("savedfilepath", filePath());
-
-	emit projectInformationsChanged(this);
-	updateDiagramsFolioData();
-
+	m_stamped_path = m_file_path;
+	m_stamped_undo_index = m_undo_stack->index();
 	setModified(false);
 	return(QETResult());
 }
@@ -3637,6 +3695,41 @@ void QETProject::readDiagramsXml(QDomDocument &xml_project)
 		}
 	}
 
+		//Symbols sharing a uuid (copies made by older versions, F100): the
+		//project database, links and wires name a symbol by its uuid, so
+		//each copy but one gets its own (renewedSharedUuid()). The copy
+		//that keeps it is the first one linked to another symbol (a
+		//partner's link names the uuid), else the first. The folios with
+		//a copy to renew are built now, also with lazy folios, so the
+		//whole project has one uuid per symbol from the start.
+	m_shared_uuid_keepers.clear();
+	QSet<int> build_now;
+	{
+		QHash<QUuid, QList<std::tuple<int, int, bool>>> copies;
+		for (int i = 0 ; i < diagram_nodes.length() ; ++i) {
+			const QDomElement elements = diagram_nodes.at(i).toElement()
+					.firstChildElement(QStringLiteral("elements"));
+			QHash<QUuid, int> ordinal;
+			for (QDomElement e = elements.firstChildElement(QStringLiteral("element"));
+				 !e.isNull() ; e = e.nextSiblingElement(QStringLiteral("element"))) {
+				const QUuid uuid(e.attribute(QStringLiteral("uuid")));
+				if (uuid.isNull()) continue;
+				const bool linked = !e.firstChildElement(QStringLiteral("links_uuids"))
+						.firstChildElement(QStringLiteral("link_uuid")).isNull();
+				copies[uuid].append({i, ordinal[uuid]++, linked});
+			}
+		}
+		for (auto it = copies.cbegin() ; it != copies.cend() ; ++it) {
+			if (it.value().size() < 2) continue;
+			auto keeper = it.value().first();
+			for (const auto &copy : it.value())
+				if (std::get<2>(copy)) { keeper = copy; break; }
+			m_shared_uuid_keepers.insert(it.key(), {std::get<0>(keeper), std::get<1>(keeper)});
+			for (const auto &copy : it.value())
+				if (copy != keeper) build_now.insert(std::get<0>(copy));
+		}
+	}
+
 	if(dlgWaiting)
 		dlgWaiting->setProgressBarRange(0, diagram_nodes.length()*3);
 
@@ -3690,7 +3783,7 @@ void QETProject::readDiagramsXml(QDomDocument &xml_project)
 			connect(diagram, &Diagram::usedTitleBlockTemplateChanged,
 					this, &QETProject::usedTitleBlockTemplateChanged);
 
-			m_deferring_folios = m_lazy_open;
+			m_deferring_folios = m_lazy_open && !build_now.contains(i);
 			diagram->initFromXml(diagram_xml_element);
 			m_deferring_folios = false;
 			if (!diagram->isLoaded() && !line_starts.isEmpty())
@@ -3703,6 +3796,7 @@ void QETProject::readDiagramsXml(QDomDocument &xml_project)
 		}
 	}
 
+	m_shared_uuid_keepers.clear();
 	updateDiagramsFolioData();
 
 		//Initialise links between elements in this project

sources/qetproject.h

@@ -123,6 +123,8 @@ class QETProject : public QObject
 		projectDataBase *dataBase();
 		QUuid uuid() const;
 		QUuid derivedItemUuid(const QString &kind, const QString &key);
+		QUuid renewedSharedUuid(int folio_index, int ordinal, const QUuid &uuid,
+								const QUuid &folio_uuid);
 		QByteArray containerPicture(const QString &file) const;
 		ProjectState state() const;
 		QString openError() const;
@@ -441,6 +443,7 @@ class QETProject : public QObject
 		}
 
 	private:
+		bool stampSaved();
 		void readProjectXml(QDomDocument &xml_project);
 		void readDiagramsXml(QDomDocument &xml_project);
 		void readElementsCollectionXml(QDomDocument &xml_project);
@@ -570,6 +573,10 @@ class QETProject : public QObject
 		bool m_kept_folios_trusted = false;
 			/// Read from a .qet whose path nobody chose since: saved beside it
 		bool m_opened_from_qet = false;
+			/// The file the saved date and path were set for, and the undo
+			/// index then: an unchanged project keeps them (stampSaved())
+		QString m_stamped_path;
+		int m_stamped_undo_index = 0;
 			/// The project file as this QET last read or wrote it, to see
 			/// whether something else changed it since (changedOnDisk())
 		QString m_disk_path;
@@ -610,7 +617,11 @@ class QETProject : public QObject
 		int m_next_backup_slot = 0;
 		QUuid m_uuid = QUuid::createUuid();
 		QHash<QString, int> m_derived_uuid_keys;
-		QSet<QUuid> m_saved_item_uuids;	//symbol and wire uuids the file carries, see derivedItemUuid()
+		QSet<QUuid> m_saved_item_uuids;
+			/// While opening: per uuid carried by several symbols, the copy
+			/// keeping it (folio index, ordinal on that folio), see
+			/// renewedSharedUuid()
+		QHash<QUuid, std::pair<int, int>> m_shared_uuid_keepers;	//symbol and wire uuids the file carries, see derivedItemUuid()
 		projectDataBase m_data_base;
 		QVector<TerminalStrip *> m_terminal_strip_vector;
 		QVector<Cable *> m_cables;

tests/qttest/CMakeLists.txt

@@ -889,6 +889,18 @@ if(QET_HAS_SCRIPTING)
   target_compile_definitions(tst_scriptconductoruuid PRIVATE
     "QET_TEST_BINARY_PATH=\"$<TARGET_FILE:qelectrotech>\"")
 
+  # The saved date, time and path of the title block change only when the
+  # project changed, and go into the file that save writes (F124): an
+  # unchanged project saved twice gives an identical file.
+  add_executable(
+    tst_savedstamps
+    tst_savedstamps.cpp)
+  add_test(NAME tst_savedstamps COMMAND tst_savedstamps)
+  add_dependencies(tst_savedstamps qelectrotech)
+  target_link_libraries(tst_savedstamps PRIVATE Qt::Test Qt::Xml)
+  target_compile_definitions(tst_savedstamps PRIVATE
+    "QET_TEST_BINARY_PATH=\"$<TARGET_FILE:qelectrotech>\"")
+
   # Deleting a symbol whose terminal held several wires joins them with a
   # new wire; its uuid comes from its two ends, so the same deletion saves
   # the same file every time (F115): examples/affuteuse_250h.qet.

tests/qttest/tst_projectlock.cpp

@@ -214,7 +214,9 @@ class tst_projectlock : public QObject
 
 		void readOnlyFolderDoesNotBlock()
 		{
-#ifndef Q_OS_WIN
+#ifdef Q_OS_WIN
+			QSKIP("a read-only folder still takes new files on Windows");
+#else
 			if (geteuid() == 0)
 				QSKIP("root can write anywhere");
 #endif

tests/qttest/tst_reporttextafterinfo.cpp

@@ -69,10 +69,12 @@ private slots:
 		f.close();
 
 			// Columns numbered from 1, as QElectroTech's settings page
-			// shows by default
+			// shows by default. Written to an INI file QET_SETTINGS_DIR
+			// points at: on Windows the settings are in the registry
+			// otherwise, and the columns would count from 0
 		const QString home = m_dir.filePath(tag + QStringLiteral("-home"));
-		QVERIFY(QDir().mkpath(home + QStringLiteral("/config/QElectroTech")));
-		QFile conf(home + QStringLiteral("/config/QElectroTech/QElectroTech.conf"));
+		QVERIFY(QDir().mkpath(home + QStringLiteral("/settings/QElectroTech")));
+		QFile conf(home + QStringLiteral("/settings/QElectroTech/QElectroTech.ini"));
 		QVERIFY(conf.open(QIODevice::WriteOnly));
 		conf.write("[General]\nborder-columns_0=false\n");
 		conf.close();
@@ -80,6 +82,7 @@ private slots:
 		QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
 		env.insert(QStringLiteral("QT_QPA_PLATFORM"), QStringLiteral("offscreen"));
 		env.insert(QStringLiteral("QET_ENABLE_SCRIPTING"), QStringLiteral("1"));
+		env.insert(QStringLiteral("QET_SETTINGS_DIR"), home + QStringLiteral("/settings"));
 		env.insert(QStringLiteral("HOME"), home);
 		env.insert(QStringLiteral("XDG_CONFIG_HOME"), home + QStringLiteral("/config"));
 		env.insert(QStringLiteral("XDG_DATA_HOME"), home + QStringLiteral("/data"));

tests/qttest/tst_resaveunchanged.cpp

@@ -411,14 +411,15 @@ private slots:
 
 	// QElectroTech run in a sandbox of its own with @p args, the store
 	// check on (QET_CHECK_ELEMENT_INFO_STORE); its output
-	QString runChecked(const QStringList &args, bool eager = false)
+	QString runChecked(const QStringList &args, bool eager = false,
+					   const char *check = "QET_CHECK_ELEMENT_INFO_STORE")
 	{
 		const QString home = m_dir.filePath(QStringLiteral("home%1").arg(m_run++));
 		QDir().mkpath(home);
 		QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
 		env.insert(QStringLiteral("QT_QPA_PLATFORM"), QStringLiteral("offscreen"));
 		env.insert(QStringLiteral("QET_ENABLE_SCRIPTING"), QStringLiteral("1"));
-		env.insert(QStringLiteral("QET_CHECK_ELEMENT_INFO_STORE"), QStringLiteral("1"));
+		env.insert(QString::fromLatin1(check), QStringLiteral("1"));
 		if (eager) {
 			env.insert(QStringLiteral("QET_EAGER_FOLIOS"), QStringLiteral("1")); //every folio built on opening
 		}
@@ -452,6 +453,31 @@ private slots:
 		QVERIFY2(out.contains(QStringLiteral("wire properties store: 0 differ")), qPrintable(out.right(600)));
 	}
 
+	// The link rows say what each symbol saves, in its order, also after
+	// an edit builds a partner's folio (lazy folios): m_000 as a .qetz
+	// saved with every folio built, a symbol of its middle folio moved. The rows used to follow the order
+	// the partners were built in (QETZ-DB-FIRST stage 2a).
+	void linkRowsAfterLazyEdit()
+	{
+		const QString qetz = m_dir.filePath(QStringLiteral("links%1.qetz").arg(m_run));
+		QVERIFY(!runChecked({QStringLiteral("--resave"),
+							 QStringLiteral(QET_EXAMPLES_DIR "/m_000.qet"), qetz}, true).isEmpty());
+		const QString saved = m_dir.filePath(QStringLiteral("links-moved%1.qetz").arg(m_run));
+		const QString js = m_dir.filePath(QStringLiteral("links%1.js").arg(m_run));
+		QFile script(js);
+		QVERIFY(script.open(QIODevice::WriteOnly));
+		script.write(QStringLiteral(
+			"var f = Math.floor(qet.folioCount() / 2);\n"
+			"var u = qet.elementUuids(f).slice().sort()[0];\n"
+			"qet.log('MOVED ' + qet.moveElement(f, u, 0, 100));\n"
+			"qet.save('%1');\n").arg(saved).toUtf8());
+		script.close();
+		const QString out = runChecked({QStringLiteral("--run"), js, qetz}, false,
+									   "QET_CHECK_LINK_ROWS");
+		QVERIFY2(out.contains(QStringLiteral("MOVED true")), qPrintable(out.right(600)));
+		QVERIFY2(out.contains(QStringLiteral("link rows: 0 differ")), qPrintable(out.right(600)));
+	}
+
 	// The stores filled from the document before the folios are built
 	// hold what building them gives, for a
 	// project saved by this version (every symbol, folio and wire carries

tests/qttest/tst_savedstamps.cpp

@@ -0,0 +1,143 @@
+/*
+	Copyright 2006-2026 The QElectroTech Team
+	This file is part of QElectroTech.
+
+	QElectroTech is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 2 of the License, or
+	(at your option) any later version.
+
+	QElectroTech is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include <QtTest>
+#include <QDate>
+#include <QDomDocument>
+#include <QProcess>
+#include <QTemporaryDir>
+
+/**
+	The title block variables of a save (saveddate, savedtime,
+	savedfilename, savedfilepath...) are set when the project is saved
+	with something new in it, and go into the file that save writes. They
+	used to be set after writing, so each save wrote the time of the one
+	before: a project saved twice without a change gave two different
+	files, and a changed project was saved with the previous date.
+
+	Runs the real binary on fixtures/unlinked_contact_label.qet, whose
+	stamps say 2026-10-02 18:39 in a temporary folder:
+	- saved twice in its own file without a change: byte-identical;
+	- one symbol moved, then saved: today's date and the file's own path.
+*/
+class tst_savedstamps : public QObject
+{
+	Q_OBJECT
+
+	QTemporaryDir m_dir;
+	QString m_base;
+
+	QString run(const QStringList &arguments)
+	{
+		QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
+		env.insert(QStringLiteral("QT_QPA_PLATFORM"), QStringLiteral("offscreen"));
+			//Its own settings and single-instance socket: another test's
+			//QElectroTech running at the same time would otherwise be
+			//handed this run (SingleApplication)
+		const QString home = m_dir.filePath(QStringLiteral("home"));
+		QDir().mkpath(home);
+		env.insert(QStringLiteral("HOME"), home);
+		env.insert(QStringLiteral("XDG_CONFIG_HOME"), home + QStringLiteral("/config"));
+		env.insert(QStringLiteral("XDG_DATA_HOME"), home + QStringLiteral("/data"));
+		env.insert(QStringLiteral("TMPDIR"), m_dir.path());
+		env.insert(QStringLiteral("QET_ENABLE_SCRIPTING"), QStringLiteral("1"));
+		QProcess proc;
+		proc.setProcessEnvironment(env);
+		proc.setProcessChannelMode(QProcess::MergedChannels);
+		proc.start(QStringLiteral(QET_TEST_BINARY_PATH), arguments);
+		if (!proc.waitForFinished(120000) || proc.exitStatus() != QProcess::NormalExit
+				|| proc.exitCode() != 0)
+			return QString();
+		return QString::fromUtf8(proc.readAll()) + QStringLiteral("\nEXIT 0");
+	}
+
+	QString script(const QString &name, const QString &body)
+	{
+		const QString path = m_dir.filePath(name);
+		QFile file(path);
+		if (!file.open(QIODevice::WriteOnly)) return QString();
+		file.write(body.toUtf8());
+		return path;
+	}
+
+		/// The saved-* properties of @p qetz, read back through --resave
+	QMap<QString, QString> stamps(const QString &qetz)
+	{
+		const QString xml = qetz + QStringLiteral(".qet");
+		if (run({QStringLiteral("--resave"), qetz, xml}).isEmpty()) return {};
+		QFile file(xml);
+		QDomDocument doc;
+		if (!file.open(QIODevice::ReadOnly) || !doc.setContent(&file)) return {};
+		QMap<QString, QString> out;
+		const QDomNodeList props = doc.documentElement().firstChildElement(
+					QStringLiteral("properties")).elementsByTagName(QStringLiteral("property"));
+		for (int i = 0; i < props.size(); ++i) {
+			const QDomElement p = props.at(i).toElement();
+			if (p.attribute(QStringLiteral("name")).startsWith(QLatin1String("saved")))
+				out.insert(p.attribute(QStringLiteral("name")), p.text());
+		}
+		return out;
+	}
+
+	static QByteArray bytes(const QString &path)
+	{
+		QFile file(path);
+		return file.open(QIODevice::ReadOnly) ? file.readAll() : QByteArray();
+	}
+
+private slots:
+	void initTestCase()
+	{
+		QVERIFY2(QFile::exists(QStringLiteral(QET_TEST_BINARY_PATH)), "qelectrotech binary not found");
+		QVERIFY(m_dir.isValid());
+		const QString fixture = QFINDTESTDATA("fixtures/unlinked_contact_label.qet");
+		QVERIFY2(!fixture.isEmpty(), "fixture project not found");
+			//The fixture as a .qetz, its stamps as they were: a copy
+			//written by --resave is not a save of the project
+		m_base = m_dir.filePath(QStringLiteral("base.qetz"));
+		QVERIFY(!run({QStringLiteral("--resave"), fixture, m_base}).isEmpty());
+		QCOMPARE(stamps(m_base).value(QStringLiteral("saveddate-us")), QStringLiteral("2026-10-02"));
+	}
+
+	void unchangedSavesAreIdentical()
+	{
+		const QString project = m_dir.filePath(QStringLiteral("unchanged.qetz"));
+		QVERIFY(QFile::copy(m_base, project));
+		const QString js = script(QStringLiteral("unchanged.js"),
+			QStringLiteral("qet.save('');\nqet.save('');\nqet.log('SAVED twice');\n"));
+		QVERIFY(run({QStringLiteral("--run"), js, project}).contains(QLatin1String("SAVED twice")));
+		QCOMPARE(bytes(project), bytes(m_base));
+	}
+
+	void changedSaveIsStampedNow()
+	{
+		const QString project = m_dir.filePath(QStringLiteral("changed.qetz"));
+		QVERIFY(QFile::copy(m_base, project));
+		const QString js = script(QStringLiteral("changed.js"), QStringLiteral(
+			"var u = qet.elementUuids(0)[0];\n"
+			"qet.log('MOVED ' + qet.moveElement(0, u, 10, 0));\n"
+			"qet.save('');\n"));
+		QVERIFY(run({QStringLiteral("--run"), js, project}).contains(QLatin1String("MOVED true")));
+		const QMap<QString, QString> s = stamps(project);
+		QCOMPARE(s.value(QStringLiteral("saveddate-us")), QDate::currentDate().toString(QStringLiteral("yyyy-MM-dd")));
+		QCOMPARE(s.value(QStringLiteral("savedfilepath")), QFileInfo(project).absoluteFilePath());
+		QCOMPARE(s.value(QStringLiteral("savedfilename")), QStringLiteral("changed"));
+	}
+};
+
+QTEST_GUILESS_MAIN(tst_savedstamps)
+#include "tst_savedstamps.moc"

tests/qttest/tst_sharedsymboluuid.cpp

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 #include <QtTest>
+#include <QSet>
 
 #include <QDomDocument>
 #include <QFile>
@@ -150,13 +151,66 @@ private slots:
 		QVERIFY(!twice.isEmpty());
 		QCOMPARE(nets(twice), expected);
 
-			//No wire names a lamp by the uuid they share
-		for (const QDomElement &c : childElements(firstDiagram(load(twice)),
-											 QStringLiteral("conductors"),
-											 QStringLiteral("conductor"))) {
-			QVERIFY(c.attribute(QStringLiteral("element1")) != shared);
-			QVERIFY(c.attribute(QStringLiteral("element2")) != shared);
+			//Each lamp has a uuid of its own after a save: one keeps the
+			//shared uuid, the others get one derived from it
+		QSet<QString> uuids;
+		for (const QDomElement &e : lamps(load(twice)))
+			uuids.insert(e.attribute(QStringLiteral("uuid")));
+		QCOMPARE(uuids.size(), 3);
+		QVERIFY(uuids.contains(shared));
+	}
+
+	// A linked contact and an unlinked symbol carrying the same uuid (a copy
+	// made by an older version): the linked one keeps the uuid, the other
+	// gets its own, and every link and wire stays where it was.
+	void linkedCopyKeepsUuid()
+	{
+		const QString source = QStringLiteral(QET_EXAMPLES_DIR "/affuteuse_250h.qet");
+		QDomDocument doc = load(source);
+		QList<QDomElement> all;
+		const QDomNodeList folios = doc.documentElement().elementsByTagName(QStringLiteral("diagram"));
+		for (int i = 0; i < folios.size(); ++i)
+			all << childElements(folios.at(i).toElement(), QStringLiteral("elements"),
+								 QStringLiteral("element"));
+		auto linked = [](const QDomElement &e) {
+			return !e.firstChildElement(QStringLiteral("links_uuids"))
+					.firstChildElement(QStringLiteral("link_uuid")).isNull();
+		};
+		QDomElement keeper, copy;
+		for (const QDomElement &e : std::as_const(all)) {
+			if (keeper.isNull() && linked(e)) keeper = e;
+			else if (copy.isNull() && !linked(e)) copy = e;
 		}
+		QVERIFY(!keeper.isNull() && !copy.isNull());
+		const QString shared = keeper.attribute(QStringLiteral("uuid"));
+		copy.setAttribute(QStringLiteral("uuid"), shared);
+		const int wires = doc.elementsByTagName(QStringLiteral("conductor")).size();
+
+		const QString saved = resave(write(doc));
+		QVERIFY(!saved.isEmpty());
+		const QDomDocument out = load(saved);
+		QHash<QString, QDomElement> by_uuid;
+		QList<std::pair<QString, QString>> links;
+		const QDomNodeList saved_folios = out.documentElement().elementsByTagName(QStringLiteral("diagram"));
+		for (int i = 0; i < saved_folios.size(); ++i)
+			for (const QDomElement &e : childElements(saved_folios.at(i).toElement(),
+													  QStringLiteral("elements"),
+													  QStringLiteral("element"))) {
+				const QString u = e.attribute(QStringLiteral("uuid"));
+				QVERIFY2(!by_uuid.contains(u), qPrintable(QStringLiteral("uuid still shared: ") + u));
+				by_uuid.insert(u, e);
+				for (QDomElement l = e.firstChildElement(QStringLiteral("links_uuids"))
+						 .firstChildElement(QStringLiteral("link_uuid"));
+					 !l.isNull(); l = l.nextSiblingElement(QStringLiteral("link_uuid")))
+					links.append({u, l.attribute(QStringLiteral("uuid"))});
+			}
+		QVERIFY(by_uuid.contains(shared));
+		QVERIFY(linked(by_uuid.value(shared)));
+		for (const auto &link : std::as_const(links)) {
+			QVERIFY2(by_uuid.contains(link.second), "a link names a symbol not in the project");
+			QVERIFY2(links.contains(std::make_pair(link.second, link.first)), "a link only one side has");
+		}
+		QCOMPARE(out.elementsByTagName(QStringLiteral("conductor")).size(), wires);
 	}
 
 	void savedByUuidReopensRight()