Race Condition when loading Qml Types. results in false errors

investigating the bug https://bugreports.qt.io/browse/QTCREATORBUG-29155 where opening the MCU automotive demo and opening automotive.qml results in false "Unknown Component" errors (there is unknown properties as well but that was fixed using qmltypes from the MCU side)
 
The unknown components however are available in the project root directory in the same folder as the importing file
adding some logs shows that the folder is imported and searched
 
imports printed in qmljscontext.cpp::contextLookupType importObj->all (joined with paths) :

thread 5f80 File:automotive.qml, Type:PerformanceMetrics QML|C:/Qt/QtMCUs/2.5.0/demos/automotive|QtQuick|QtQuickUltralite/Extras|Automotive

 
Adding two logging point , MCUIMPORT in (qmljslink::importFileOrDirectory) and MCUSNAPSHOT in (qmljsdocument.cpp::Snapshot::insert) shows that the syntax check is being performed while the snapshot is still being feed new components (logs with different thread number)

5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/Navi.qml5820 MCUSNAPSHOT> Loading C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalMode.qml
5820 MCUSNAPSHOT> Inserted C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalMode.qml
5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalMode.qml
5820 MCUSNAPSHOT> Loading C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalMode.qml
5820 MCUSNAPSHOT> Inserted C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalMode.qml
5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalMode.qml
5820 MCUSNAPSHOT> Loading C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalModeContentItem.qml
5820 MCUSNAPSHOT> Inserted C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalModeContentItem.qml
5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalModeContentItem.qml
5820 MCUSNAPSHOT> Loading C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalModeContentItem.qml
5820 MCUSNAPSHOT> Inserted C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalModeContentItem.qml
5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/NormalModeContentItem.qml
5820 MCUSNAPSHOT> Loading C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetricItem.qml
5820 MCUSNAPSHOT> Inserted C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetricItem.qml
5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetricItem.qml
5820 MCUSNAPSHOT> Loading C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetricItem.qml
5820 MCUSNAPSHOT> Inserted C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetricItem.qml
5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetricItem.qml
5f80 MCUIMPORT> C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> type is a directory importing lib
5f80 MCUIMPORT> Size of documents in dir16
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added BaseGauge
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added CarStatus
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added DriveModeSelector
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added Gauge
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added GuideArrow
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added GuideArrowItem
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added LaneAssist
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added LaneAssistWhiteLine
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added LinearGauge
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added MediaPlayer
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added Menu
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added MiddleGauge
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added Navi
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added NormalMode
5f80 MCUIMPORT> type is a directory importing doc C:/Qt/QtMCUs/2.5.0/demos/automotive
5f80 MCUIMPORT> Member added NormalModeContentItem
5820 MCUSNAPSHOT> Loading C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetrics.qml
5820 MCUSNAPSHOT> Inserted C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetrics.qml
5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetrics.qml
5820 MCUSNAPSHOT> Loading C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetrics.qml
5820 MCUSNAPSHOT> Inserted C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetrics.qml
5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/PerformanceMetrics.qml
5820 MCUSNAPSHOT> Loading C:/Qt/QtMCUs/2.5.0/demos/automotive/Phone.qml
5820 MCUSNAPSHOT> Inserted C:/Qt/QtMCUs/2.5.0/demos/automotive/Phone.qml
5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/Phone.qml
5820 MCUSNAPSHOT> Loading C:/Qt/QtMCUs/2.5.0/demos/automotive/Phone.qml
5820 MCUSNAPSHOT> Inserted C:/Qt/QtMCUs/2.5.0/demos/automotive/Phone.qml
5820 MCUSNAPSHOT> Done C:/Qt/QtMCUs/2.5.0/demos/automotive/Phone.qm

 
 
One attempt to solve this was to use test_joinAllThreads() to wait for the modelManager futures to finish in qmljssemanticinfoupdater.cpp::makeNewSemanticInfo

Linklink(semanticInfo.snapshot, modelManager->defaultVContext(doc->language(), doc), modelManager->builtins(doc));
modelManager->test_joinAllThreads();
semanticInfo.context=link(doc, &semanticInfo.semanticMessages);
 

 
The order is then correct (snapshot is filled with all items before the checker() is called). but the error persist as it seems the checker still use an outdated snapshot copy (passed to the constructor)