From 22d4ef8fbf6bea3b4df176af096d3412f3bf67ec Mon Sep 17 00:00:00 2001
From: Mathieu Pellerin <nirvn.asia@gmail.com>
Date: Sun, 24 Mar 2024 15:01:43 +0700
Subject: [PATCH 1/2] Now that we allow children creation prior to parent
 creation, we need to update default values to take possible children into
 consideration

---
 src/core/featuremodel.cpp | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/src/core/featuremodel.cpp b/src/core/featuremodel.cpp
index b500ebdfd5..1170e36472 100644
--- a/src/core/featuremodel.cpp
+++ b/src/core/featuremodel.cpp
@@ -740,11 +740,13 @@ bool FeatureModel::create()
     return false;
   }
 
+  bool hasRelations = false;
   QList<QPair<QgsRelation, QgsFeatureRequest>> revisitRelations;
   if ( mProject )
   {
     // Gather any relationship children which would have relied on an auto-generated field value
     const QList<QgsRelation> relations = mProject->relationManager()->referencedRelations( mLayer );
+    hasRelations = !relations.isEmpty();
     QgsFeature temporaryFeature = mFeature;
     for ( const QgsRelation &relation : relations )
     {
@@ -781,25 +783,32 @@ bool FeatureModel::create()
       QgsFeature feat;
       if ( mLayer->getFeatures( QgsFeatureRequest().setFilterFid( createdFeatureId ) ).nextFeature( feat ) )
       {
-        // Revisit relations in need of attribute updates
-        for ( const QPair<QgsRelation, QgsFeatureRequest> &revisitRelation : std::as_const( revisitRelations ) )
+        setFeature( feat );
+
+        if ( hasRelations )
         {
-          const QList<QgsRelation::FieldPair> fieldPairs = revisitRelation.first.fieldPairs();
-          revisitRelation.first.referencingLayer()->startEditing();
-          QgsFeatureIterator it = revisitRelation.first.referencingLayer()->getFeatures( revisitRelation.second );
-          QgsFeature childFeature;
-          while ( it.nextFeature( childFeature ) )
+          // Revisit relations in need of attribute updates
+          for ( const QPair<QgsRelation, QgsFeatureRequest> &revisitRelation : std::as_const( revisitRelations ) )
           {
-            for ( const QgsRelation::FieldPair fieldPair : fieldPairs )
+            const QList<QgsRelation::FieldPair> fieldPairs = revisitRelation.first.fieldPairs();
+            revisitRelation.first.referencingLayer()->startEditing();
+            QgsFeatureIterator it = revisitRelation.first.referencingLayer()->getFeatures( revisitRelation.second );
+            QgsFeature childFeature;
+            while ( it.nextFeature( childFeature ) )
             {
-              childFeature.setAttribute( fieldPair.referencingField(), feat.attribute( fieldPair.referencedField() ) );
+              for ( const QgsRelation::FieldPair fieldPair : fieldPairs )
+              {
+                childFeature.setAttribute( fieldPair.referencingField(), feat.attribute( fieldPair.referencedField() ) );
+              }
+              revisitRelation.first.referencingLayer()->updateFeature( childFeature );
             }
-            revisitRelation.first.referencingLayer()->updateFeature( childFeature );
+            revisitRelation.first.referencingLayer()->commitChanges();
           }
-          revisitRelation.first.referencingLayer()->commitChanges();
-        }
 
-        setFeature( feat );
+          // We need to update default values after creation to insure expression relying on relation children computer properly
+          updateDefaultValues();
+          save();
+        }
       }
       else
       {

From 4d4f46e7e4c2514ad5164fab62908fe64d1c2cd0 Mon Sep 17 00:00:00 2001
From: Mathieu Pellerin <nirvn.asia@gmail.com>
Date: Sun, 24 Mar 2024 16:54:37 +0700
Subject: [PATCH 2/2] fix typo

Co-authored-by: Matthias Kuhn <matthias@opengis.ch>
---
 src/core/featuremodel.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/core/featuremodel.cpp b/src/core/featuremodel.cpp
index 1170e36472..04e1377a3e 100644
--- a/src/core/featuremodel.cpp
+++ b/src/core/featuremodel.cpp
@@ -805,7 +805,7 @@ bool FeatureModel::create()
             revisitRelation.first.referencingLayer()->commitChanges();
           }
 
-          // We need to update default values after creation to insure expression relying on relation children computer properly
+          // We need to update default values after creation to insure expression relying on relation children compute properly
           updateDefaultValues();
           save();
         }