[processing] Fix use of models as child algorithms in other models

nyalldawson · nyalldawson · commit cdd72e51e5c1 · 2018-09-19T05:04:09.000+10:00
Fixes #19857
diff --git a/src/core/processing/models/qgsprocessingmodelalgorithm.cpp b/src/core/processing/models/qgsprocessingmodelalgorithm.cpp
@@ -930,6 +930,16 @@ bool QgsProcessingModelAlgorithm::vectorOutputIsCompatibleType( const QList<int>
                 outputType == QgsProcessing::TypeVectorPolygon ) ) );
 }
 
+void QgsProcessingModelAlgorithm::reattachAlgorithms() const
+{
+  QMap< QString, QgsProcessingModelChildAlgorithm >::const_iterator childIt = mChildAlgorithms.constBegin();
+  for ( ; childIt != mChildAlgorithms.constEnd(); ++childIt )
+  {
+    if ( !childIt->algorithm() )
+      childIt->reattach();
+  }
+}
+
 bool QgsProcessingModelAlgorithm::toFile( const QString &path ) const
 {
   QDomDocument doc = QDomDocument( QStringLiteral( "model" ) );
@@ -1182,6 +1192,7 @@ QSet< QString > QgsProcessingModelAlgorithm::dependsOnChildAlgorithms( const QSt
 
 bool QgsProcessingModelAlgorithm::canExecute( QString *errorMessage ) const
 {
+  reattachAlgorithms();
   QMap< QString, QgsProcessingModelChildAlgorithm >::const_iterator childIt = mChildAlgorithms.constBegin();
   for ( ; childIt != mChildAlgorithms.constEnd(); ++childIt )
   {
diff --git a/src/core/processing/models/qgsprocessingmodelalgorithm.h b/src/core/processing/models/qgsprocessingmodelalgorithm.h
@@ -416,6 +416,11 @@ class CORE_EXPORT QgsProcessingModelAlgorithm : public QgsProcessingAlgorithm
      */
     static bool vectorOutputIsCompatibleType( const QList<int> &acceptableDataTypes, QgsProcessing::SourceType outputType );
 
+    /**
+     * Tries to reattach all child algorithms to their linked algorithms.
+     */
+    void reattachAlgorithms() const;
+
     friend class TestQgsProcessing;
 };
 
diff --git a/tests/src/analysis/testqgsprocessing.cpp b/tests/src/analysis/testqgsprocessing.cpp
@@ -5750,7 +5750,14 @@ void TestQgsProcessing::modelerAlgorithm()
   alg2.addChildAlgorithm( c6 );
   QVERIFY( !alg2.canExecute() );
 
-
+  // test that children are re-attached before testing for canExecute
+  QgsProcessingModelAlgorithm alg2a( "test", "testGroup" );
+  QgsProcessingModelChildAlgorithm c5a;
+  c5a.setAlgorithmId( "native:centroids" );
+  alg2a.addChildAlgorithm( c5a );
+  // simulate initially missing provider or algorithm (e.g. another model as a child algorithm)
+  alg2a.mChildAlgorithms.begin().value().mAlgorithm.reset();
+  QVERIFY( alg2a.canExecute() );
 
   // dependencies
   QgsProcessingModelAlgorithm alg3( "test", "testGroup" );

Original file line number	Diff line number	Diff line change
`@@ -930,6 +930,16 @@ bool QgsProcessingModelAlgorithm::vectorOutputIsCompatibleType( const QList<int>`
`930`	`930`	`outputType == QgsProcessing::TypeVectorPolygon ) ) );`
`931`	`931`	`}`
`932`	`932`
	`933`	`+void QgsProcessingModelAlgorithm::reattachAlgorithms() const`
	`934`	`+{`
	`935`	`+ QMap< QString, QgsProcessingModelChildAlgorithm >::const_iterator childIt = mChildAlgorithms.constBegin();`
	`936`	`+ for ( ; childIt != mChildAlgorithms.constEnd(); ++childIt )`
	`937`	`+ {`
	`938`	`+ if ( !childIt->algorithm() )`
	`939`	`+ childIt->reattach();`
	`940`	`+ }`
	`941`	`+}`
	`942`	`+`
`933`	`943`	`bool QgsProcessingModelAlgorithm::toFile( const QString &path ) const`
`934`	`944`	`{`
`935`	`945`	`QDomDocument doc = QDomDocument( QStringLiteral( "model" ) );`
`@@ -1182,6 +1192,7 @@ QSet< QString > QgsProcessingModelAlgorithm::dependsOnChildAlgorithms( const QSt`
`1182`	`1192`
`1183`	`1193`	`bool QgsProcessingModelAlgorithm::canExecute( QString *errorMessage ) const`
`1184`	`1194`	`{`
	`1195`	`+ reattachAlgorithms();`
`1185`	`1196`	`QMap< QString, QgsProcessingModelChildAlgorithm >::const_iterator childIt = mChildAlgorithms.constBegin();`
`1186`	`1197`	`for ( ; childIt != mChildAlgorithms.constEnd(); ++childIt )`
`1187`	`1198`	`{`