MPS-28875 Cannot use a node from checkpoint model in reference macro

do not resolve nodes in a model scheduled for removal

Author: artem-tikhomirov

core/generator/source/jetbrains/mps/generator/TransientModelsModule.java

@@ -43,10 +43,8 @@
 import org.jetbrains.mps.openapi.module.SModule;
 import org.jetbrains.mps.openapi.module.SModuleReference;
 import org.jetbrains.mps.openapi.module.SRepository;
-import org.jetbrains.mps.openapi.persistence.ModelSaveException;
 import org.jetbrains.mps.openapi.persistence.NullDataSource;
 
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -200,7 +198,7 @@ public String toString() {
 
   // Purpose of this implementation is to resolve references to yet not public transient models
   private SModel findInVault(SModelId reference) {
-    for (SModel m : myModelVault.allModels()) {
+    for (SModel m : myModelVault.allModelsExceptScheduled2Drop()) {
       if (reference.equals(m.getModelId())) {
         return m;
       }
@@ -211,7 +209,8 @@ private SModel findInVault(SModelId reference) {
   @Override
   public SModel getModel(SModelId id) {
     SModel rv = super.getModel(id);
-    if (rv != null) {
+    // we may find CP model published during previous generator run but already re-generated (and scheduled to drop) during actual run.
+    if (rv != null && !myModelVault.isScheduled2Drop(rv)) {
       return rv;
     }
     return findInVault(id);
@@ -404,7 +403,7 @@ public boolean isChanged() {
     }
 
     @Override
-    protected boolean saveModel() throws IOException, ModelSaveException {
+    protected boolean saveModel() {
       throw new UnsupportedOperationException();
     }
 

core/generator/source/jetbrains/mps/generator/impl/ModelVault.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2003-2016 JetBrains s.r.o.
+ * Copyright 2003-2018 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -95,6 +95,24 @@ public Iterable<T> allModels() {
     return new ArrayList<>(myModels);
   }
 
+  // XXX not sure there's need for distinct method or it shall be part of allModels() impl,
+  //     nor am I sure we shall not resolve references into models to drop (I'd rather do).
+  //     However, imagine there's already model m1@cp in a checkpoint module, and we generate m1 and m2 (latter needs to use m1@cp)
+  //     When we see m1's new checkpoint, CME.createBlankCheckpointModel recognizes there's already m1@cp and commands to forget it (vault.forgetModel())
+  //     Then, m2 restores a reference to m1@cp with a node from new CP model (m1'@cp), but the reference is kept as 'mature', and the moment we resolve it,
+  //     the code in TransientModelsModule.findInVault() just took the first model from allModels() with matching id, which could be the m1@cp one, not m1'@cp
+  //     (they share same module reference, after all).
+  public Iterable<T> allModelsExceptScheduled2Drop() {
+    final ArrayList<T> rv = new ArrayList<>(myModels);
+    rv.removeAll(myExactModelsToDrop.keySet());
+    return rv;
+  }
+
+  public boolean isScheduled2Drop(SModel model) {
+    return myExactModelsToDrop.containsKey(model);
+  }
+
+
   public boolean known(@NotNull SModelReference mr) {
     for (SModel m : myModels) {
       if (mr.equals(m.getReference())) {