Turn relative path into absolute path for reading embedded projects.

src/core/qgsproject.cpp

@@ -972,7 +972,7 @@ bool QgsProject::_getMapLayers( const QDomDocument &doc, QList<QDomNode> &broken
 
     if ( element.attribute( QStringLiteral( "embedded" ) ) == QLatin1String( "1" ) )
     {
-      createEmbeddedLayer( element.attribute( QStringLiteral( "id" ) ), readPath( element.attribute( QStringLiteral( "project" ) ) ), brokenNodes, flags );
+      createEmbeddedLayer( element.attribute( QStringLiteral( "id" ) ), readPath( element.attribute( QStringLiteral( "project" ) ) ), brokenNodes, true, flags );
     }
     else
     {
@@ -1543,9 +1543,9 @@ bool QgsProject::readProjectFile( const QString &filename, QgsProject::ReadFlags
 }
 
 
-void QgsProject::loadEmbeddedNodes( QgsLayerTreeGroup *group, QgsProject::ReadFlags flags )
+bool QgsProject::loadEmbeddedNodes( QgsLayerTreeGroup *group, QgsProject::ReadFlags flags )
 {
-
+  bool valid = true;
   const auto constChildren = group->children();
   for ( QgsLayerTreeNode *child : constChildren )
   {
@@ -1579,11 +1579,16 @@ void QgsProject::loadEmbeddedNodes( QgsLayerTreeGroup *group, QgsProject::ReadFl
       if ( child->customProperty( QStringLiteral( "embedded" ) ).toInt() )
       {
         QList<QDomNode> brokenNodes;
-        createEmbeddedLayer( QgsLayerTree::toLayer( child )->layerId(), child->customProperty( QStringLiteral( "embedded_project" ) ).toString(), brokenNodes, flags );
+        if ( ! createEmbeddedLayer( QgsLayerTree::toLayer( child )->layerId(), readPath( child->customProperty( QStringLiteral( "embedded_project" ) ).toString() ), brokenNodes, true, flags ) )
+        {
+          valid = valid && false;
+        }
       }
     }
 
   }
+
+  return valid;
 }
 
 QVariantMap QgsProject::customVariables() const

src/core/qgsproject.h

@@ -1703,7 +1703,7 @@ class CORE_EXPORT QgsProject : public QObject, public QgsExpressionContextGenera
      * The optional \a flags argument can be used to control layer reading behavior.
      * \note not available in Python bindings
      */
-    void loadEmbeddedNodes( QgsLayerTreeGroup *group, QgsProject::ReadFlags flags = nullptr ) SIP_SKIP;
+    bool loadEmbeddedNodes( QgsLayerTreeGroup *group, QgsProject::ReadFlags flags = nullptr ) SIP_SKIP;
 
     //! Read .qgs file
     bool readProjectFile( const QString &filename, QgsProject::ReadFlags flags = nullptr );
@@ -1798,6 +1798,8 @@ class CORE_EXPORT QgsProject : public QObject, public QgsExpressionContextGenera
 
     // Required by QGIS Server for switching the current project instance
     friend class QgsConfigCache;
+
+    friend class TestQgsProject;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS( QgsProject::ReadFlags )

tests/src/core/testqgsproject.cpp

@@ -20,6 +20,7 @@
 #include "qgsmarkersymbollayer.h"
 #include "qgspathresolver.h"
 #include "qgsproject.h"
+#include "qgslayertree.h"
 #include "qgssinglesymbolrenderer.h"
 #include "qgssettings.h"
 #include "qgsunittypes.h"
@@ -483,6 +484,18 @@ void TestQgsProject::testEmbeddedLayerGroupFromQgz()
 
   QCOMPARE( p1.layerIsEmbedded( points->id() ), path );
   QCOMPARE( p1.layerIsEmbedded( polys->id() ), path );
+
+  // test embedded layers when origin project is something like ../XXX
+  path = QString( TEST_DATA_DIR ) + QStringLiteral( "/embedded_layers/project.qgz" );
+  QgsProject p2;
+  p2.read( path );
+
+  QgsMapLayer *points2 = p0.mapLayersByName( "points" )[0];
+  bool saveFlag = p2.mEmbeddedLayers[points2->id()].second;
+  QCOMPARE( saveFlag, true );
+
+  bool valid = p2.loadEmbeddedNodes( p2.layerTreeRoot() );
+  QCOMPARE( valid, true );
 }
 
 void TestQgsProject::testSetGetCrs()