Fix crash in network content fetcher when run from non-main thread

nyalldawson · nyalldawson · commit 1d28bbe0cecb · 2018-07-29T09:33:45.000+10:00
Because a QNetworkAccessManager is the parent for all QNetworkReplys created by it, if a reply is created in a thread then we need to ensure that this reply isn't deleted early by destruction of the thread local QgsNetworkAcessManager instance. Work around this by unsetting the parent for the QNetworkReplys owned by QgsNetworkContentFetcher objects. Fixes #19452 (cherry-picked from 7f84b6c)
diff --git a/src/core/qgsnetworkcontentfetcher.cpp b/src/core/qgsnetworkcontentfetcher.cpp
@@ -55,6 +55,7 @@ void QgsNetworkContentFetcher::fetchContent( const QNetworkRequest &request )
   }
 
   mReply = QgsNetworkAccessManager::instance()->get( request );
+  mReply->setParent( nullptr ); // we don't want thread locale QgsNetworkAccessManagers to delete the reply - we want ownership of it to belong to this object
   connect( mReply, &QNetworkReply::finished, this, [ = ] { contentLoaded(); } );
   connect( mReply, &QNetworkReply::downloadProgress, this, &QgsNetworkContentFetcher::downloadProgress );
 }

Original file line number	Diff line number	Diff line change
`@@ -55,6 +55,7 @@ void QgsNetworkContentFetcher::fetchContent( const QNetworkRequest &request )`
`55`	`55`	`}`
`56`	`56`
`57`	`57`	`mReply = QgsNetworkAccessManager::instance()->get( request );`
	`58`	`+ mReply->setParent( nullptr ); // we don't want thread locale QgsNetworkAccessManagers to delete the reply - we want ownership of it to belong to this object`
`58`	`59`	`connect( mReply, &QNetworkReply::finished, this, [ = ] { contentLoaded(); } );`
`59`	`60`	`connect( mReply, &QNetworkReply::downloadProgress, this, &QgsNetworkContentFetcher::downloadProgress );`
`60`	`61`	`}`