From e22399af826b582e330a2772460d3bc0d98eb558 Mon Sep 17 00:00:00 2001
From: Laszlo Agocs <laszlo.agocs@qt.io>
Date: Thu, 3 Oct 2019 17:33:23 +0200
Subject: [PATCH] Make QRhi::create() return false when there is no MTLDevice

The interesting part here is that sending messages to a null
object is valid in Objective-C, so without an explicit check it
is not necessarily straightforward to discover that we do not
have working rendering. (because the application won't just
simply crash)

Do the right thing now and return false like other backends do.

Task-number: QTBUG-78994
Change-Id: I0d3c4a49a3fc78f9149f8af4fe67d581e74daae7
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>
---
 src/gui/rhi/qrhimetal.mm | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/gui/rhi/qrhimetal.mm b/src/gui/rhi/qrhimetal.mm
index e55513277b..9c579ebfe1 100644
--- a/src/gui/rhi/qrhimetal.mm
+++ b/src/gui/rhi/qrhimetal.mm
@@ -367,6 +367,11 @@ bool QRhiMetal::create(QRhi::Flags flags)
     else
         d->dev = MTLCreateSystemDefaultDevice();
 
+    if (!d->dev) {
+        qWarning("No MTLDevice");
+        return false;
+    }
+
     qCDebug(QRHI_LOG_INFO, "Metal device: %s", qPrintable(QString::fromNSString([d->dev name])));
 
     if (importedCmdQueue)