From f8dba0395f6024d5d6a7b3112b9970693cb55dfd Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Fri, 24 Mar 2023 08:44:53 +0100
Subject: [PATCH] QPromise: add support for addResult(braced-initializer)
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The usual problem, the usual fix: default the addResult() template
argument to the class template argument, cf. e.g. wg21.link/p2218.

[ChangeLog][QtCore][QPromise] Added support for calls to addResult()
with braced initializers.

Fixes: QTBUG-111826
Change-Id: I9ad7294dbcefbc5d2609ca3d9e7304dbeb8b3f41
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
---
 src/corelib/thread/qpromise.h                     |  2 +-
 .../auto/corelib/thread/qpromise/tst_qpromise.cpp | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/corelib/thread/qpromise.h b/src/corelib/thread/qpromise.h
index 9be9526ef6..9db58ad595 100644
--- a/src/corelib/thread/qpromise.h
+++ b/src/corelib/thread/qpromise.h
@@ -46,7 +46,7 @@ public:
 
     // Core QPromise APIs
     QFuture<T> future() const { return d.future(); }
-    template<typename U, typename = QtPrivate::EnableIfSameOrConvertible<U, T>>
+    template<typename U = T, typename = QtPrivate::EnableIfSameOrConvertible<U, T>>
     bool addResult(U &&result, int index = -1)
     {
         return d.reportResult(std::forward<U>(result), index);
diff --git a/tests/auto/corelib/thread/qpromise/tst_qpromise.cpp b/tests/auto/corelib/thread/qpromise/tst_qpromise.cpp
index 6c23884b36..09332f92ef 100644
--- a/tests/auto/corelib/thread/qpromise/tst_qpromise.cpp
+++ b/tests/auto/corelib/thread/qpromise/tst_qpromise.cpp
@@ -24,6 +24,7 @@ private slots:
     void promise();
     void futureFromPromise();
     void addResult();
+    void addResultWithBracedInitializer();
     void addResultOutOfOrder();
 #ifndef QT_NO_EXCEPTIONS
     void setException();
@@ -196,6 +197,20 @@ void tst_QPromise::addResult()
     }
 }
 
+void tst_QPromise::addResultWithBracedInitializer() // QTBUG-111826
+{
+    struct MyClass
+    {
+        QString strValue;
+        int intValue = 0;
+    };
+
+    {
+        QPromise<MyClass> myPromise;
+        myPromise.addResult({"bar", 1});
+    }
+}
+
 void tst_QPromise::addResultOutOfOrder()
 {
     // Compare results available in QFuture to expected results