Spaces without a quota limit display "undefined" as the storage line

[greve]

Summary

Ran into this when packaging OpenCloud Desktop for Fedora COPR:

For a Space whose quota is unlimited (server reports total == 0), the folder/Space list shows the literal text undefined where the storage usage line should be usage only, or be hidden. The account otherwise connects and syncs normally; only the storage label is wrong.

Steps to reproduce

1. Connect the client to an OpenCloud server whose Spaces have no quota limit (capabilities: "spaces":{"max_quota":0,…}; GET /graph/v1.0/me/drives returns drives whose quota.total is 0/absent).
2. Open the account view that lists the Spaces.

Expected behavior

• no storage line (or an "unlimited" indication) for unlimited Spaces.

Actual behavior

• the storage line reads undefined.

Setup

• OpenCloud Desktop 3.0.3 (commit 72fe8f), virtual files plugin: off
• Fedora 44 w/ Qt 6.11.1, OpenSSL 3.5.7, Wayland, Linux x86_64
• Server: OpenCloud 4.0.7, Spaces enabled, max_quota: 0
• Packages with patch in https://copr.fedorainfracloud.org/coprs/greve/opencloud-desktop/

Root cause

src/gui/folderstatusmodel.cpp, FolderStatusModel::data(), Roles::Quota:

case Roles::Quota: {
    qint64 used{};
    qint64 total{};
    if (auto *space = f->space()) {
        const auto quota = space->drive().getQuota();
        if (quota.isValid()) {
            used = quota.getUsed();
            total = quota.getTotal();
        }
    }
    if (total <= 0) {
        return {};   // <-- invalid QVariant()
    }
    return tr("%1 of %2 used").arg(Utility::octetsToString(used), Utility::octetsToString(total));
}

The role is consumed in src/gui/qml/FolderDelegate.qml as a typed string:

required property string quota
...
text: folderDelegate.quota
visible: folderDelegate.quota && !folderDelegate.overallText

When total <= 0, data() returns an invalid QVariant(). Assigned to a required property string, that becomes the JS value undefined, which stringifies to the literal "undefined". The visible: guard then sees a non-empty (truthy) string and shows the label. An empty QString would instead coerce to "", which the guard treats as false and hides as a minimal fix.

The invalid-variant → string coercion is stricter on newer Qt (seen with Qt 6.11); the underlying defect: returning an invalid variant for a role bound to a typed string property is version-independent.

Suggested fix (one line)

         if (total <= 0) {
-            return {};
+            return QString();
         }

This hides the storage line for unlimited Spaces via the existing visible: guard. (A follow-up could instead show "X used" or an "Unlimited" label, but the minimal correctness fix is to stop rendering undefined.)