From 33f59dd3ecc7d6de195d5de7d50c1cde0c951abe Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 1 May 2017 11:29:02 +0300
Subject: [PATCH] Fix an infinite recursion in Emoji panel/section.

HistoryWidget::resizeEvent() can start taking TabbedSelector from
TabbedPanel which will call QWidget::render() which can call again
HistoryWidget::resizeEvent() from sendPendingMoveAndResizeEvents().

Use a separate flag for _tabbedSection to prevent recursion there.
---
 Telegram/SourceFiles/historywidget.cpp | 12 ++++++++----
 Telegram/SourceFiles/historywidget.h   |  1 +
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/Telegram/SourceFiles/historywidget.cpp b/Telegram/SourceFiles/historywidget.cpp
index 1b9ff4afbd..820bd6f209 100644
--- a/Telegram/SourceFiles/historywidget.cpp
+++ b/Telegram/SourceFiles/historywidget.cpp
@@ -3699,13 +3699,17 @@ void HistoryWidget::topBarClick() {
 
 void HistoryWidget::updateTabbedSelectorSectionShown() {
 	auto tabbedSelectorSectionEnabled = AuthSession::Current().data().tabbedSelectorSectionEnabled();
-	auto shown = tabbedSelectorSectionEnabled && (width() >= minimalWidthForTabbedSelectorSection());
-	auto shownNow = (_tabbedSection != nullptr);
-	if (shown == shownNow) {
+	auto useTabbedSection = tabbedSelectorSectionEnabled && (width() >= minimalWidthForTabbedSelectorSection());
+	if (_tabbedSectionUsed == useTabbedSection) {
 		return;
 	}
+	_tabbedSectionUsed = useTabbedSection;
 
-	if (shown) {
+	// Use a separate bool flag instead of just (_tabbedSection != nullptr), because
+	// _tabbedPanel->takeSelector() calls QWidget::render(), which calls
+	// sendPendingMoveAndResizeEvents() for all widgets in the window, which can lead
+	// to a new HistoryWidget::resizeEvent() call and an infinite recursion here.
+	if (_tabbedSectionUsed) {
 		_tabbedSection.create(this, _controller, _tabbedPanel->takeSelector());
 		_tabbedSection->setCancelledCallback([this] { setInnerFocus(); });
 		_rightShadow.create(this, st::shadowFg);
diff --git a/Telegram/SourceFiles/historywidget.h b/Telegram/SourceFiles/historywidget.h
index 9f1dbbb37b..e8141307bd 100644
--- a/Telegram/SourceFiles/historywidget.h
+++ b/Telegram/SourceFiles/historywidget.h
@@ -790,6 +790,7 @@ private:
 	object_ptr<ChatHelpers::TabbedPanel> _tabbedPanel;
 	object_ptr<ChatHelpers::TabbedSection> _tabbedSection = { nullptr };
 	QPointer<ChatHelpers::TabbedSelector> _tabbedSelector;
+	bool _tabbedSectionUsed = false;
 	DragState _attachDrag = DragStateNone;
 	object_ptr<DragArea> _attachDragDocument, _attachDragPhoto;