[processing] prevent circular dependencies in models

fixes #99090

Author: volaya

python/plugins/processing/modeler/ModelerDialog.py

@@ -164,10 +164,6 @@ def _mimeDataAlgorithm(items):
         self.btnEditHelp.setIcon(QIcon(os.path.join(pluginPath, 'images', 'edithelp.png')))
         self.btnRun.setIcon(QIcon(os.path.join(pluginPath, 'images', 'runalgorithm.png')))
 
-        # Fill trees with inputs and algorithms
-        self.fillInputsTree()
-        self.fillAlgorithmTree()
-
         if hasattr(self.searchBox, 'setPlaceholderText'):
             self.searchBox.setPlaceholderText(self.tr('Search...'))
         if hasattr(self.textName, 'setPlaceholderText'):
@@ -198,6 +194,9 @@ def _mimeDataAlgorithm(items):
             self.alg = ModelerAlgorithm()
             self.alg.modelerdialog = self
 
+        self.fillInputsTree()
+        self.fillAlgorithmTree()
+
         self.view.centerOn(0, 0)
         self.alg.setModelerView(self)
         self.help = None
@@ -484,6 +483,8 @@ def fillAlgorithmTreeUsingProviders(self):
             for alg in algs:
                 if not alg.showInModeler or alg.allowOnlyOpenedLayers:
                     continue
+                if alg.commandLineName() == self.alg.commandLineName():
+                    continue
                 if text == '' or text.lower() in alg.name.lower():
                     if alg.group in groups:
                         groupItem = groups[alg.group]