debug: add lint for zero sized items

src/debug/lint.cpp

@@ -0,0 +1,81 @@
+#include "lint.hpp"
+#include <algorithm>
+
+#include <qlogging.h>
+#include <qloggingcategory.h>
+#include <qobject.h>
+#include <qqmlcontext.h>
+#include <qqmlengine.h>
+#include <qqmlinfo.h>
+#include <qquickframebufferobject.h>
+#include <qquickitem.h>
+#include <qquickpainteditem.h>
+#include <qquickrhiitem.h>
+#include <qquickwindow.h>
+#include <qstringliteral.h>
+
+namespace qs::debug {
+
+Q_LOGGING_CATEGORY(logLint, "quickshell.linter", QtWarningMsg);
+
+void lintZeroSized(QQuickItem* item);
+bool isRenderable(QQuickItem* item);
+
+void lintObjectTree(QObject* object) {
+	if (!logLint().isWarningEnabled()) return;
+
+	qCDebug(logLint) << "Walking children of object" << object;
+
+	for (auto* child: object->children()) {
+		if (child->isQuickItemType()) {
+			auto* item = static_cast<QQuickItem*>(child); // NOLINT;
+			lintItemTree(item);
+		} else {
+			lintObjectTree(child);
+		}
+	}
+}
+
+void lintItemTree(QQuickItem* item) {
+	if (!logLint().isWarningEnabled()) return;
+
+	qCDebug(logLint) << "Running lints for item" << item;
+	lintZeroSized(item);
+
+	qCDebug(logLint) << "Walking visual children of item" << item;
+	for (auto* child: item->childItems()) {
+		lintItemTree(child);
+	}
+}
+
+void lintZeroSized(QQuickItem* item) {
+	if (!item->isEnabled() || !item->isVisible()) return;
+	if (item->childItems().isEmpty()) return;
+
+	auto zeroWidth = item->width() == 0;
+	auto zeroHeight = item->height() == 0;
+
+	if (!zeroWidth && !zeroHeight) return;
+
+	if (!isRenderable(item)) return;
+
+	auto* ctx = QQmlEngine::contextForObject(item);
+	if (!ctx || ctx->baseUrl().scheme() != QStringLiteral("qsintercept")) return;
+
+	qmlWarning(item) << "Item is visible and has visible children, but has zero "
+	                 << (zeroWidth && zeroHeight ? "width and height"
+	                     : zeroWidth             ? "width"
+	                                             : "height");
+}
+
+bool isRenderable(QQuickItem* item) {
+	if (!item->isEnabled() || !item->isVisible()) return false;
+
+	if (item->flags().testFlags(QQuickItem::ItemHasContents)) {
+		return true;
+	}
+
+	return std::ranges::any_of(item->childItems(), [](auto* item) { return isRenderable(item); });
+}
+
+} // namespace qs::debug