Fix assignability analysis for prematurely read fields

DEVELOPING_OPAL/validate/src/test/java/org/opalj/fpcf/fixtures/immutability/openworld/assignability/advanced_counter_examples/PrematurelyReadFinalField.java

@@ -0,0 +1,35 @@
+/* BSD 2-Clause License - see OPAL/LICENSE for details. */
+package org.opalj.fpcf.fixtures.immutability.openworld.assignability.advanced_counter_examples;
+
+import org.opalj.fpcf.properties.immutability.field_assignability.AssignableField;
+
+/**
+ * The default value of the field x is assigned to another field n during construction and as
+ * a result seen with two different values.
+ */
+public class PrematurelyReadFinalField {
+
+    @AssignableField("Field n is assigned with different values.")
+    static int n = 5;
+
+    public static void main(String[] args) {
+        C c = new C();
+    }
+}
+
+class B {
+    B() {
+        PrematurelyReadFinalField.n = ((C) this).x;
+    }
+}
+
+class C extends B {
+
+    @AssignableField("Is seen with two different values during construction.")
+    public final int x;
+
+    C() {
+        super();
+        x = 3;
+    }
+}

DEVELOPING_OPAL/validate/src/test/java/org/opalj/fpcf/fixtures/immutability/openworld/assignability/advanced_counter_examples/ThisEscapesDuringConstruction.java

@@ -0,0 +1,23 @@
+/* BSD 2-Clause License - see OPAL/LICENSE for details. */
+package org.opalj.fpcf.fixtures.immutability.openworld.assignability.advanced_counter_examples;
+
+import org.opalj.fpcf.properties.immutability.field_assignability.AssignableField;
+
+/**
+ * This test case simulates the fact that the `this` object escapes in the constructor before (final) fields
+ * are assigned.
+ */
+public class ThisEscapesDuringConstruction {
+
+   @AssignableField("The this object escapes in the constructor before the field is assigned.")
+   final int n;
+
+    public ThisEscapesDuringConstruction() {
+        C2.m(this);
+        n = 7;
+    }
+}
+
+class C2 {
+    public static void m(ThisEscapesDuringConstruction c) {}
+}

DEVELOPING_OPAL/validate/src/test/java/org/opalj/fpcf/fixtures/immutability/openworld/assignability/advanced_counter_examples/ValueReadBeforeAssignment.java

@@ -0,0 +1,25 @@
+/* BSD 2-Clause License - see OPAL/LICENSE for details. */
+package org.opalj.fpcf.fixtures.immutability.openworld.assignability.advanced_counter_examples;
+
+import org.opalj.fpcf.properties.immutability.field_assignability.AssignableField;
+
+/**
+ * The value of the field x is read with its default value (0)
+ * in the constructor before assignment and assigned to a public field.
+ * Thus, the value can be accessed from everywhere.
+ */
+public class ValueReadBeforeAssignment {
+    @AssignableField("Field value is read before assignment.")
+    private int x;
+    @AssignableField("Field y is public and not final.")
+    public int y;
+
+    public ValueReadBeforeAssignment() {
+        y = x;
+        x = 42;
+    }
+
+    public ValueReadBeforeAssignment foo() {
+        return new ValueReadBeforeAssignment();
+    }
+}

DEVELOPING_OPAL/validate/src/test/java/org/opalj/fpcf/fixtures/immutability/openworld/assignability/clone_function/SimpleClonePattern.java

@@ -15,7 +15,7 @@
 public final class SimpleClonePattern {
 
     @TransitivelyImmutableField("Field is effectively non assignable and has a primitive type")
-    @EffectivelyNonAssignableField("Field is only assigned ones due to the clone function pattern")
+    @EffectivelyNonAssignableField("Field is only assigned once due to the clone function pattern")
     private int i;
 
     public SimpleClonePattern clone(){
@@ -28,7 +28,7 @@ public SimpleClonePattern clone(){
 class CloneNonAssignableWithNewObject {
 
     @TransitivelyImmutableField("field is effectively non assignable and assigned with a transitively immutable object")
-    @EffectivelyNonAssignableField("field is only assigned ones due to the clone function pattern")
+    @EffectivelyNonAssignableField("field is only assigned once due to the clone function pattern")
     private Integer integer;
 
     public CloneNonAssignableWithNewObject clone(){
@@ -41,7 +41,7 @@ public CloneNonAssignableWithNewObject clone(){
 class EscapesAfterAssignment {
 
     @TransitivelyImmutableField("field is effectively non assignable and assigned with a transitively immutable object")
-    @EffectivelyNonAssignableField("field is only assigned ones due to the clone function pattern")
+    @EffectivelyNonAssignableField("field is only assigned once due to the clone function pattern")
     private Integer integer;
 
     private Integer integerCopy;
@@ -77,7 +77,7 @@ public MultipleFieldsAssignedInCloneFunction clone(){
 class ConstructorWithParameter {
 
     @TransitivelyImmutableField("field is effectively non assignable and has a transitively immutable type")
-    @EffectivelyNonAssignableField("field is only assigned ones due to the clone function pattern")
+    @EffectivelyNonAssignableField("field is only assigned once due to the clone function pattern")
     private Integer integer;
 
     public ConstructorWithParameter(Integer integer){

DEVELOPING_OPAL/validate/src/test/java/org/opalj/fpcf/fixtures/immutability/openworld/lazyinitialization/objects/DifferentLazyInitializedFieldTypes.java

@@ -16,8 +16,8 @@
  */
 public class DifferentLazyInitializedFieldTypes {
 
-     @TransitivelyImmutableField("Lazy initialized field with primitive type.")
-     @LazilyInitializedField("field is thread safely lazy initialized")
+    @TransitivelyImmutableField("Lazy initialized field with primitive type.")
+    @LazilyInitializedField("field is thread safely lazy initialized")
     private int inTheGetterLazyInitializedIntField;
 
     public synchronized int getInTheGetterLazyInitializedIntField(){

OPAL/br/src/main/scala/org/opalj/br/fpcf/properties/immutability/FieldAssignability.scala

@@ -34,6 +34,8 @@ sealed trait FieldAssignability extends OrderedProperty with FieldAssignabilityP
     final def key: PropertyKey[FieldAssignability] = FieldAssignability.key
 
     def isImmutable = false
+
+    def meet(other: FieldAssignability): FieldAssignability
 }
 
 object FieldAssignability extends FieldAssignabilityPropertyMetaInformation {
@@ -73,9 +75,9 @@ case object EffectivelyNonAssignable extends NonAssignableField {
 
     def meet(other: FieldAssignability): FieldAssignability =
         if (other == NonAssignable) {
-            other
-        } else {
             this
+        } else {
+            other
         }
 }