From ba26496647bca4b37fc2319b553b95966823b941 Mon Sep 17 00:00:00 2001
From: Lars Knoll <lars.knoll@qt.io>
Date: Tue, 8 Oct 2019 13:16:00 +0200
Subject: [PATCH] Don't crash when calling jumpToFrame() on an empty QMovie

Properly return an invalid frame when calling jumpToFrame()
with a non existent frame number.

Fixes: QTBUG-79029
Change-Id: Ic40f4a6de3106fab42c0bb6c961194be47b04e31
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>
---
 src/gui/image/qmovie.cpp                   | 2 +-
 tests/auto/gui/image/qmovie/tst_qmovie.cpp | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/gui/image/qmovie.cpp b/src/gui/image/qmovie.cpp
index 79203c7b98..f03c8836df 100644
--- a/src/gui/image/qmovie.cpp
+++ b/src/gui/image/qmovie.cpp
@@ -416,7 +416,7 @@ QFrameInfo QMoviePrivate::infoForFrame(int frameNumber)
             } else {
                 // We've read all frames now. Return an end marker
                 haveReadAll = true;
-                return QFrameInfo::endMarker();
+                return frameNumber == greatestFrameNumber + 1 ? QFrameInfo::endMarker() : QFrameInfo();
             }
         }
     }
diff --git a/tests/auto/gui/image/qmovie/tst_qmovie.cpp b/tests/auto/gui/image/qmovie/tst_qmovie.cpp
index 4e9e9b8115..c8217b2cec 100644
--- a/tests/auto/gui/image/qmovie/tst_qmovie.cpp
+++ b/tests/auto/gui/image/qmovie/tst_qmovie.cpp
@@ -62,6 +62,7 @@ private slots:
 #ifndef QT_NO_WIDGETS
     void infiniteLoop();
 #endif
+    void emptyMovie();
 };
 
 // Testing get/set functions
@@ -220,5 +221,13 @@ void tst_QMovie::infiniteLoop()
 }
 #endif
 
+void tst_QMovie::emptyMovie()
+{
+    QMovie movie;
+    movie.setCacheMode(QMovie::CacheAll);
+    movie.jumpToFrame(100);
+    QCOMPARE(movie.currentFrameNumber(), -1);
+}
+
 QTEST_MAIN(tst_QMovie)
 #include "tst_qmovie.moc"