Merge branch 'f-fix-deleted-old-reference' into 'dev'

f-fix-deleted-old-reference -> dev

See merge request caosdb/caosdb-server!61

CHANGELOG.md

@@ -25,6 +25,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+* Semi-fixed a bug which occurs when retrieving old versions of entities which
+  reference entities which have been deleted in the mean time. The current fix
+  adds a warning message to the reference property in question and sets the
+  value to NULL. This might even be desired behavior, however this would have
+  to finally specified during the Delete/Forget phase of the implementation of
+  the versioning.
 - Inheritance job cannot handle inheritance from same container (!54)
 * Bug in the query parser (MR!56) - The parser would throw an error when the
   query contains a conjunction or disjunction filter with a first element which

src/main/java/org/caosdb/server/database/DatabaseUtils.java

@@ -258,7 +258,8 @@ public class DatabaseUtils {
     }
   }
 
-  private static void replace(final Property p, final HashMap<Integer, Property> domainMap) {
+  private static void replace(
+      final Property p, final HashMap<Integer, Property> domainMap, boolean isHead) {
     // ... find the corresponding domain and replace it
     ReferenceValue ref;
     try {
@@ -267,6 +268,17 @@ public class DatabaseUtils {
       throw new RuntimeException("This should never happen.");
     }
     final EntityInterface replacement = domainMap.get((ref.getId()));
+    if (replacement == null) {
+      if (isHead) {
+        throw new NullPointerException("Replacement was null");
+      }
+      // entity has been deleted (we are processing properties of an old entity version)
+      p.setValue(null);
+      p.addWarning(
+          new Message(
+              "The referenced entity has been deleted in the mean time and is not longer available."));
+      return;
+    }
     if (replacement.isDescOverride()) {
       p.setDescOverride(true);
       p.setDescription(replacement.getDescription());
@@ -314,15 +326,18 @@ public class DatabaseUtils {
     }
 
     // loop over all properties
+    boolean isHead =
+        e.getVersion().getSuccessors() == null || e.getVersion().getSuccessors().isEmpty();
     for (final Property p : protoProperties) {
+
       // if this is a replacement
       if (p.getStatementStatus() == StatementStatus.REPLACEMENT) {
-        replace(p, domainMap);
+        replace(p, domainMap, isHead);
       }
 
       for (final Property subP : p.getProperties()) {
         if (subP.getStatementStatus() == StatementStatus.REPLACEMENT) {
-          replace(subP, domainMap);
+          replace(subP, domainMap, isHead);
         }
       }
 

src/main/java/org/caosdb/server/database/backend/transaction/RetrieveFullEntity.java

@@ -102,12 +102,12 @@ public class RetrieveFullEntity extends BackendTransaction {
     execute(new RetrieveSparseEntity(e));
 
     if (e.getEntityStatus() == EntityStatus.VALID) {
+      execute(new RetrieveVersionInfo(e));
       if (e.getRole() == Role.QueryTemplate) {
         execute(new RetrieveQueryTemplateDefinition(e));
       }
       execute(new RetrieveParents(e));
       execute(new RetrieveProperties(e));
-      execute(new RetrieveVersionInfo(e));
 
       // recursion! retrieveSubEntities calls retrieveFull sometimes, but with reduced selectors.
       if (selections != null && !selections.isEmpty()) {

src/main/java/org/caosdb/server/entity/Entity.java

@@ -957,7 +957,8 @@ public class Entity extends AbstractObservable implements EntityInterface {
 
   @Override
   public String toString() {
-    return (hasId() ? "(" + getId().toString() + ")" : "()")
+    return (getRole().toString())
+        + (hasId() ? "(" + getId().toString() + ")" : "()")
         + (hasCuid() ? "[" + getCuid() + "]" : "[]")
         + (hasName() ? "(" + getName() + ")" : "()")
         + (hasDatatype() ? "{" + getDatatype().toString() + "}" : "{}");

src/main/java/org/caosdb/server/entity/wrapper/Property.java

@@ -120,7 +120,7 @@ public class Property extends EntityWrapper {
 
   @Override
   public String toString() {
-    return "IMPLPROPERTY " + this.entity.toString();
+    return "IMPLPROPERTY (" + this.getStatementStatus() + ")" + this.entity.toString();
   }
 
   public void setIsName(final boolean b) {