feat: VariationDiff::computeAllFeatureNames()

Author: pmbittner

src/main/java/org/variantsync/diffdetective/variation/diff/VariationDiff.java

@@ -24,6 +24,7 @@
 import org.variantsync.diffdetective.variation.diff.traverse.VariationDiffTraversal;
 import org.variantsync.diffdetective.variation.diff.traverse.VariationDiffVisitor;
 import org.variantsync.diffdetective.variation.tree.VariationTree;
+import org.variantsync.diffdetective.util.fide.FixTrueFalse;
 import org.variantsync.functjonal.Cast;
 import org.variantsync.functjonal.Result;
 
@@ -374,6 +375,25 @@ public int count(final Predicate<DiffNode<L>> nodesToCount) {
         return count.get();
     }
 
+
+    /**
+     * Returns all variable names occurring in annotations (i.e., formulas of mapping nodes) in this variation diff.
+     * This method is deterministic: It will return the feature names always in the same order, assuming the variation diff is not changed inbetween.
+     * @return A list of every occuring feature name.
+     */
+    public List<String> computeAllFeatureNames() {
+        List<String> features = new ArrayList<>();
+        forAll(node -> {
+                if (node.isConditionalAnnotation()) {
+                    features.addAll(node.getFormula().getUniqueContainedFeatures());
+                }
+            });
+        // Since FeatureIDE falsely reports constants "True" and "False" as feature names, we have to remove them from the resulting set.
+        features.removeIf(FixTrueFalse::isTrueLiteral);
+        features.removeIf(FixTrueFalse::isFalseLiteral);
+        return features;
+    }
+
     /**
      * Sets the source of this VariationDiff.
      * @see VariationDiffSource