fix(accounts): keep pending values over reads answered before the change lands

accounts/tests/accountsmanager_test.cpp

@@ -2,6 +2,7 @@
 #include "usersmodel.h"
 
 #include <QtCore/QProcess>
+#include <QtCore/QTimer>
 #include <QtDBus/QDBusAbstractAdaptor>
 #include <QtDBus/QDBusConnectionInterface>
 #include <QtDBus/QDBusInterface>
@@ -26,6 +27,7 @@ class TestUserAdaptor : public QDBusAbstractAdaptor
     Q_PROPERTY(QString UserName READ userName)
     Q_PROPERTY(QString RealName READ realName)
     Q_PROPERTY(qulonglong Uid READ uid)
+    Q_PROPERTY(QString Email READ email)
 
 public:
     TestUserAdaptor(QObject *parent, const QString &name, qulonglong uid)
@@ -38,6 +40,7 @@ public:
     QString userName() const { return m_name; }
     QString realName() const { return m_realName; }
     qulonglong uid() const { return m_uid; }
+    QString email() const { return m_email; }
 
 public Q_SLOTS:
     void SetUserName(const QString &name)
@@ -57,12 +60,26 @@ public Q_SLOTS:
         m_realName = name;
     }
 
+    // Answers late, as behind a polkit prompt, and reports an unrelated
+    // change while the caller waits.
+    void SetEmail(const QString &address, const QDBusMessage &message)
+    {
+        message.setDelayedReply(true);
+        Q_EMIT Changed();
+        QTimer::singleShot(300, this, [this, address, message] {
+            m_email = address;
+            QDBusConnection::sessionBus().send(message.createReply());
+            Q_EMIT Changed();
+        });
+    }
+
 Q_SIGNALS:
     void Changed();
 
 private:
     QString m_name;
     QString m_realName;
+    QString m_email;
     qulonglong m_uid;
 };
 
@@ -379,6 +396,26 @@ private Q_SLOTS:
         QCOMPARE(account->realName(), QStringLiteral("Bob Current"));
     }
 
+    void aPendingChangeOutlastsReadsAnsweredMeanwhile()
+    {
+        AccountsManager manager(QDBusConnection::sessionBus());
+        QSignalSpy cached(&manager, &AccountsManager::userCached);
+        manager.cacheUser(QStringLiteral("carol"));
+        QTRY_COMPARE(cached.size(), 1);
+        UserAccount *account = manager.cachedUser(QStringLiteral("carol"));
+        QVERIFY(account);
+        QTRY_COMPARE(account->userName(), QStringLiteral("carol"));
+
+        account->setEmail(QStringLiteral("carol@example.org"));
+        QCOMPARE(account->email(), QStringLiteral("carol@example.org"));
+        for (int i = 0; i < 6; ++i) {
+            QTest::qWait(40);
+            QCOMPARE(account->email(), QStringLiteral("carol@example.org"));
+        }
+        QTest::qWait(400);
+        QCOMPARE(account->email(), QStringLiteral("carol@example.org"));
+    }
+
     void synchronousQueriesAndCreateDelete()
     {
         AccountsManager manager(QDBusConnection::sessionBus());

accounts/useraccount.cpp

@@ -46,6 +46,7 @@ void UserAccount::setObjectPath(const QString &path)
     delete d_ptr->service;
     d_ptr->objectPath = path;
     d_ptr->values.clear();
+    d_ptr->pendingValues.clear();
     d_ptr->values.insert(QStringLiteral("Uid"), path.mid(userPathPrefix.size()).toLongLong());
     d_ptr->service = new OrgFreedesktopAccountsUserInterface(serviceName, path,
                                                               d_ptr->bus, this);
@@ -107,8 +108,12 @@ void UserAccount::refresh()
             });
 }
 
-void UserAccount::applyValues(const QVariantMap &updated)
+void UserAccount::applyValues(const QVariantMap &reply)
 {
+    QVariantMap updated = reply;
+    for (auto it = d_ptr->pendingValues.cbegin(); it != d_ptr->pendingValues.cend(); ++it)
+        updated.insert(it.key(), it.value());
+
     const QVariantMap previous = d_ptr->values;
     d_ptr->values = updated;
 
@@ -154,11 +159,14 @@ void UserAccount::applyValues(const QVariantMap &updated)
 void UserAccount::watch(const QDBusPendingCall &call, void (UserAccount::*notify)(),
                         bool displayName)
 {
+    ++d_ptr->pendingSets;
     auto *watcher = new QDBusPendingCallWatcher(call, this);
     connect(watcher, &QDBusPendingCallWatcher::finished, this,
             [this, notify, displayName](QDBusPendingCallWatcher *finished) {
                 QDBusPendingReply<> reply = *finished;
                 finished->deleteLater();
+                if (--d_ptr->pendingSets == 0)
+                    d_ptr->pendingValues.clear();
                 if (reply.isError()) {
                     qWarning("AccountsService update failed: %s",
                              reply.error().message().toUtf8().constData());
@@ -179,6 +187,7 @@ void UserAccount::watch(const QDBusPendingCall &call, void (UserAccount::*notify
 void UserAccount::notePendingChange(const char *property, const QVariant &value,
                                     void (UserAccount::*notify)(), bool displayName)
 {
+    d_ptr->pendingValues.insert(QString::fromLatin1(property), value);
     d_ptr->values.insert(QString::fromLatin1(property), value);
     Q_EMIT (this->*notify)();
     if (displayName)

accounts/useraccount.h

@@ -117,7 +117,7 @@ private:
                bool displayName = false);
     void notePendingChange(const char *property, const QVariant &value,
                            void (UserAccount::*notify)(), bool displayName = false);
-    void applyValues(const QVariantMap &updated);
+    void applyValues(const QVariantMap &reply);
     QVariant value(const char *property) const;
 
     UserAccountPrivate *const d_ptr;

accounts/useraccount_p.h

@@ -17,6 +17,9 @@ public:
     QString objectPath;
     // Every getter reads from here; GetAll replies fill it asynchronously.
     QVariantMap values;
+    // Values set but not yet confirmed; a GetAll answered meanwhile still has the old ones.
+    QVariantMap pendingValues;
+    int pendingSets = 0;
     quint64 refreshSerial = 0;
 };