[pal] Always iterate through labeled layers in original layer order

Ensures that labeling solutions are deterministic
qgis · Jan 31, 2025 · 27a2846 · 27a2846
1 parent c42f86f
commit 27a2846
Show file tree

Hide file tree

Showing 2 changed files with 8 additions and 3 deletions.
diff --git a/src/core/pal/pal.cpp b/src/core/pal/pal.cpp
@@ -88,11 +88,16 @@ Layer *Pal::addLayer( QgsAbstractLabelProvider *provider, const QString &layerNa
 {
   mMutex.lock();
 
-  Q_ASSERT( mLayers.find( provider ) == mLayers.end() );
+#ifdef QGISDEBUG
+  for ( const auto &it : mLayers )
+  {
+    Q_ASSERT( it.first != provider );
+  }
+#endif
 
   std::unique_ptr< Layer > layer = std::make_unique< Layer >( provider, layerName, arrangement, defaultPriority, active, toLabel, this );
   Layer *res = layer.get();
-  mLayers.insert( std::pair<QgsAbstractLabelProvider *, std::unique_ptr< Layer >>( provider, std::move( layer ) ) );
+  mLayers.emplace_back( std::make_pair( provider, std::move( layer ) ) );
   mMutex.unlock();
 
   // cppcheck-suppress returnDanglingLifetime

diff --git a/src/core/pal/pal.h b/src/core/pal/pal.h
@@ -279,7 +279,7 @@ namespace pal
 
     private:
 
-      std::unordered_map< QgsAbstractLabelProvider *, std::unique_ptr< Layer > > mLayers;
+      std::vector< std::pair< QgsAbstractLabelProvider *, std::unique_ptr< Layer > > > mLayers;
 
       QList< QgsAbstractLabelingEngineRule * > mRules;