Database merge confirmation dialog (#10173)

* Add Entry::calculateDifference()

This new function contains the logic that was previously in
EntryHistoryModel::calculateHistoryModifications().
It allows the re-use to display the differences in case of a merge.

* Introduce Database Merge Confirmation Dialog

Adds a dialog allowing a user to review the changes of a merge operation.
This dialog displays the changes and allows the user to abort the merge
without modifying the database.

Fixes #1152

* Added dry run option to Merger
* Changed behavior when actual merge differs from dry run to just output a warning to console
* Fixed KeeShare conflicting with merge operations in the middle of a merge

---------

Co-authored-by: Jonathan White <support@dmapps.us>

src/gui/DatabaseWidget.cpp

@@ -44,6 +44,7 @@
 #include "gui/FileDialog.h"
 #include "gui/GuiTools.h"
 #include "gui/MainWindow.h"
+#include "gui/MergeDialog.h"
 #include "gui/MessageBox.h"
 #include "gui/TotpDialog.h"
 #include "gui/TotpExportSettingsDialog.h"
@@ -1387,18 +1388,30 @@ void DatabaseWidget::mergeDatabase(bool accepted)
             return;
         }
 
-        Merger merger(srcDb.data(), m_db.data());
-        QStringList changeList = merger.merge();
+#ifdef WITH_XC_KEESHARE
+        // Disable KeeShare while merging to avoid conflicts with incoming changes
+        KeeShare::instance()->setSharingEnabled(m_db, false);
+#endif
 
-        if (!changeList.isEmpty()) {
-            showMessage(tr("Successfully merged the database files."), MessageWidget::Information);
-        } else {
-            showMessage(tr("Database was not modified by merge operation."), MessageWidget::Information);
-        }
+        auto* mergeDialog = new MergeDialog(srcDb, m_db, this);
+        connect(mergeDialog, &MergeDialog::databaseMerged, [this](bool changed) {
+            if (changed) {
+                showMessage(tr("Successfully merged the selected database."), MessageWidget::Positive);
+                emit databaseMerged(m_db);
+            } else {
+                showMessage(tr("No changes were made by the merge operation."), MessageWidget::Information);
+            }
+        });
+        connect(mergeDialog, &MergeDialog::finished, [this](int result) {
+            if (result == QDialog::Rejected) {
+                showMessage(tr("Merge canceled, no changes were made."), MessageWidget::Information);
+            }
+#ifdef WITH_XC_KEESHARE
+            KeeShare::instance()->setSharingEnabled(m_db, true);
+#endif
+        });
+        mergeDialog->open();
     }
-
-    switchToMainView();
-    emit databaseMerged(m_db);
 }
 
 void DatabaseWidget::syncUnlockedDatabase(bool accepted)
@@ -1438,7 +1451,7 @@ bool DatabaseWidget::syncWithDatabase(const QSharedPointer<Database>& otherDb, Q
     emit updateSyncProgress(50, tr("Syncing..."));
     Merger firstMerge(m_db.data(), otherDb.data());
     Merger secondMerge(otherDb.data(), m_db.data());
-    QStringList changeList = firstMerge.merge() + secondMerge.merge();
+    auto changeList = firstMerge.merge() + secondMerge.merge();
 
     if (!changeList.isEmpty()) {
         // Save synced databases

src/gui/MergeDialog.cpp

@@ -0,0 +1,199 @@
+/*
+ *  Copyright (C) 2025 KeePassXC Team <team@keepassxc.org>
+ *
+ *  This program 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 or (at your option)
+ *  version 3 of the License.
+ *
+ *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "MergeDialog.h"
+#include "ui_MergeDialog.h"
+
+#include "core/Database.h"
+
+#include <QPushButton>
+#include <QShortcut>
+
+MergeDialog::MergeDialog(QSharedPointer<Database> source, QSharedPointer<Database> target, QWidget* parent)
+    : QDialog(parent)
+    , m_ui(new Ui::MergeDialog())
+    , m_headerContextMenu(new QMenu())
+    , m_sourceDatabase(std::move(source))
+    , m_targetDatabase(std::move(target))
+{
+    setAttribute(Qt::WA_DeleteOnClose);
+    // block input to other windows since other interactions can lead to unexpected merge results
+    setWindowModality(Qt::WindowModality::ApplicationModal);
+
+    m_ui->setupUi(this);
+
+    m_ui->buttonBox->button(QDialogButtonBox::Ok)->setText(tr("Merge"));
+    m_ui->buttonBox->button(QDialogButtonBox::Ok)->setFocus();
+
+    connect(m_ui->buttonBox, &QDialogButtonBox::rejected, this, &MergeDialog::cancelMerge);
+    connect(m_ui->buttonBox, &QDialogButtonBox::accepted, this, &MergeDialog::performMerge);
+
+    setupChangeTable();
+    updateChangeTable();
+}
+
+MergeDialog::MergeDialog(const Merger::ChangeList& changes, QWidget* parent)
+    : QDialog(parent)
+    , m_ui(new Ui::MergeDialog())
+    , m_headerContextMenu(new QMenu())
+    , m_changes(changes)
+{
+    setAttribute(Qt::WA_DeleteOnClose);
+
+    m_ui->setupUi(this);
+
+    m_ui->buttonBox->button(QDialogButtonBox::Ok)->setFocus();
+    m_ui->buttonBox->button(QDialogButtonBox::Abort)->hide();
+
+    connect(m_ui->buttonBox, &QDialogButtonBox::accepted, this, &MergeDialog::close);
+
+    setupChangeTable();
+}
+
+MergeDialog::~MergeDialog() = default;
+
+QVector<MergeDialog::MergeDialogColumns> MergeDialog::columns()
+{
+    return {MergeDialogColumns::Group,
+            MergeDialogColumns::Title,
+            MergeDialogColumns::Uuid,
+            MergeDialogColumns::Type,
+            MergeDialogColumns::Details};
+}
+
+int MergeDialog::columnIndex(MergeDialogColumns column)
+{
+    return columns().indexOf(column);
+}
+
+QString MergeDialog::columnName(MergeDialogColumns column)
+{
+    switch (column) {
+    case MergeDialogColumns::Group:
+        return tr("Group");
+    case MergeDialogColumns::Title:
+        return tr("Title");
+    case MergeDialogColumns::Uuid:
+        return tr("UUID");
+    case MergeDialogColumns::Type:
+        return tr("Change");
+    case MergeDialogColumns::Details:
+        return tr("Details");
+    }
+    return {};
+}
+
+QString MergeDialog::cellValue(const Merger::Change& change, MergeDialogColumns column)
+{
+    switch (column) {
+    case MergeDialogColumns::Group:
+        return change.group();
+    case MergeDialogColumns::Title:
+        return change.title();
+    case MergeDialogColumns::Uuid:
+        if (!change.uuid().isNull()) {
+            return change.uuid().toString();
+        }
+        break;
+    case MergeDialogColumns::Type:
+        return change.typeString();
+    case MergeDialogColumns::Details:
+        return change.details();
+    }
+    return {};
+}
+
+bool MergeDialog::isColumnHiddenByDefault(MergeDialogColumns column)
+{
+    return column == MergeDialogColumns::Uuid;
+}
+
+void MergeDialog::setupChangeTable()
+{
+    Q_ASSERT(m_ui);
+    Q_ASSERT(m_ui->changeTable);
+
+    m_ui->changeTable->verticalHeader()->setVisible(false);
+    m_ui->changeTable->horizontalHeader()->setSectionResizeMode(QHeaderView::ResizeMode::Interactive);
+    m_ui->changeTable->horizontalHeader()->setContextMenuPolicy(Qt::ActionsContextMenu);
+
+    m_ui->changeTable->setShowGrid(false);
+    m_ui->changeTable->setEditTriggers(QAbstractItemView::NoEditTriggers);
+    m_ui->changeTable->setSelectionBehavior(QAbstractItemView::SelectRows);
+    m_ui->changeTable->setSelectionMode(QAbstractItemView::SingleSelection);
+
+    // Create the header context menu
+    for (auto column : columns()) {
+        auto* action = new QAction(columnName(column), this);
+        action->setCheckable(true);
+        action->setChecked(!isColumnHiddenByDefault(column));
+        connect(action, &QAction::toggled, [this, column](bool checked) {
+            m_ui->changeTable->setColumnHidden(columnIndex(column), !checked);
+            m_ui->changeTable->horizontalHeader()->resizeSections(QHeaderView::ResizeMode::ResizeToContents);
+        });
+        m_ui->changeTable->horizontalHeader()->addAction(action);
+    }
+}
+
+void MergeDialog::updateChangeTable()
+{
+    Q_ASSERT(m_ui);
+    Q_ASSERT(m_ui->changeTable);
+    Q_ASSERT(m_sourceDatabase.get());
+    Q_ASSERT(m_targetDatabase.get());
+
+    m_changes = Merger(m_sourceDatabase.data(), m_targetDatabase.get()).merge(true);
+
+    m_ui->changeTable->clear();
+
+    auto allColumns = columns();
+    m_ui->changeTable->setColumnCount(allColumns.size());
+    m_ui->changeTable->setRowCount(m_changes.size());
+    for (auto column : allColumns) {
+        auto name = columnName(column);
+        auto index = columnIndex(column);
+
+        m_ui->changeTable->setHorizontalHeaderItem(index, new QTableWidgetItem(name));
+        m_ui->changeTable->setColumnHidden(index, isColumnHiddenByDefault(column));
+    }
+    for (int row = 0; row < m_changes.size(); ++row) {
+        const auto& change = m_changes[row];
+        for (auto column : allColumns) {
+            m_ui->changeTable->setItem(row, columnIndex(column), new QTableWidgetItem(cellValue(change, column)));
+        }
+    }
+
+    m_ui->changeTable->horizontalHeader()->resizeSections(QHeaderView::ResizeMode::ResizeToContents);
+}
+
+void MergeDialog::performMerge()
+{
+    auto changes = Merger(m_sourceDatabase.data(), m_targetDatabase.data()).merge();
+    if (changes != m_changes) {
+        qWarning("Merge results differed from the expected changes. Expected: %d, Actual: %d",
+                 m_changes.size(),
+                 changes.size());
+    }
+
+    emit databaseMerged(!changes.isEmpty());
+    done(QDialog::Accepted);
+}
+
+void MergeDialog::cancelMerge()
+{
+    done(QDialog::Rejected);
+}

src/gui/MergeDialog.h

@@ -0,0 +1,83 @@
+/*
+ *  Copyright (C) 2025 KeePassXC Team <team@keepassxc.org>
+ *
+ *  This program 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 or (at your option)
+ *  version 3 of the License.
+ *
+ *  This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef KEEPASSX_MERGEDIALOG_H
+#define KEEPASSX_MERGEDIALOG_H
+
+#include "core/Merger.h"
+
+#include <QDialog>
+#include <QMenu>
+
+namespace Ui
+{
+    class MergeDialog;
+}
+
+class Database;
+
+class MergeDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    /**
+     * Merge source into copy of target and display changes.
+     * On user confirmation, merge source into target.
+     */
+    explicit MergeDialog(QSharedPointer<Database> source, QSharedPointer<Database> target, QWidget* parent = nullptr);
+    /**
+     * Display given changes.
+     */
+    explicit MergeDialog(const Merger::ChangeList& changes, QWidget* parent = nullptr);
+    ~MergeDialog() override;
+
+signals:
+    // Signal will be emitted when a normal merge operation has been performed.
+    void databaseMerged(bool databaseChanged);
+
+private slots:
+    void performMerge();
+    void cancelMerge();
+
+private:
+    enum class MergeDialogColumns
+    {
+        Group,
+        Title,
+        Uuid,
+        Type,
+        Details
+    };
+    static QVector<MergeDialogColumns> columns();
+    static int columnIndex(MergeDialogColumns column);
+    static QString columnName(MergeDialogColumns column);
+    static QString cellValue(const Merger::Change& change, MergeDialogColumns column);
+    static bool isColumnHiddenByDefault(MergeDialogColumns column);
+
+    void setupChangeTable();
+    void updateChangeTable();
+
+    QScopedPointer<Ui::MergeDialog> m_ui;
+    QScopedPointer<QMenu> m_headerContextMenu;
+
+    Merger::ChangeList m_changes;
+    QSharedPointer<Database> m_sourceDatabase;
+    QSharedPointer<Database> m_targetDatabase;
+};
+
+#endif // KEEPASSX_MERGEDIALOG_H

src/gui/MergeDialog.ui

@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>MergeDialog</class>
+ <widget class="QWidget" name="MergeDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>800</width>
+    <height>450</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Database Merge Confirmation</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <widget class="QTableWidget" name="changeTable"/>
+   </item>
+   <item>
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Abort|QDialogButtonBox::Ok</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>

src/gui/entry/EntryHistoryModel.cpp

@@ -193,64 +193,7 @@ void EntryHistoryModel::calculateHistoryModifications()
             continue;
         }
 
-        QStringList modifiedFields;
-
-        if (*curr->attributes() != *compare->attributes()) {
-            bool foundAttribute = false;
-
-            if (curr->title() != compare->title()) {
-                modifiedFields << tr("Title");
-                foundAttribute = true;
-            }
-            if (curr->username() != compare->username()) {
-                modifiedFields << tr("Username");
-                foundAttribute = true;
-            }
-            if (curr->password() != compare->password()) {
-                modifiedFields << tr("Password");
-                foundAttribute = true;
-            }
-            if (curr->url() != compare->url()) {
-                modifiedFields << tr("URL");
-                foundAttribute = true;
-            }
-            if (curr->notes() != compare->notes()) {
-                modifiedFields << tr("Notes");
-                foundAttribute = true;
-            }
-
-            if (!foundAttribute) {
-                modifiedFields << tr("Custom Attributes");
-            }
-        }
-        if (curr->iconNumber() != compare->iconNumber() || curr->iconUuid() != compare->iconUuid()) {
-            modifiedFields << tr("Icon");
-        }
-        if (curr->foregroundColor() != compare->foregroundColor()
-            || curr->backgroundColor() != compare->backgroundColor()) {
-            modifiedFields << tr("Color");
-        }
-        if (curr->timeInfo().expires() != compare->timeInfo().expires()
-            || curr->timeInfo().expiryTime() != compare->timeInfo().expiryTime()) {
-            modifiedFields << tr("Expiration");
-        }
-        if (curr->totp() != compare->totp()) {
-            modifiedFields << tr("TOTP");
-        }
-        if (*curr->customData() != *compare->customData()) {
-            modifiedFields << tr("Custom Data");
-        }
-        if (*curr->attachments() != *compare->attachments()) {
-            modifiedFields << tr("Attachments");
-        }
-        if (*curr->autoTypeAssociations() != *compare->autoTypeAssociations()
-            || curr->autoTypeEnabled() != compare->autoTypeEnabled()
-            || curr->defaultAutoTypeSequence() != compare->defaultAutoTypeSequence()) {
-            modifiedFields << tr("Auto-Type");
-        }
-        if (curr->tags() != compare->tags()) {
-            modifiedFields << tr("Tags");
-        }
+        auto modifiedFields = curr->calculateDifference(compare);
 
         m_historyModifications << modifiedFields.join(", ");