fix(matching): Early return on matching if nodes have different kinds

bin/tests/scenarios/jdime_matching_issue/base.java

@@ -0,0 +1,21 @@
+package de.fosd.jdime.artifact;
+
+import java.security.MessageDigest;
+
+public abstract class Artifact<T extends Artifact<T>> implements Comparable<T>, StatisticsInterface {
+    public boolean hasChanges(Revision revision) {
+        if (this.revision.equals(revision)) {
+            return false;
+        }
+
+        if (!hasMatching(revision)) {
+            return true;
+        }
+
+        T match = getMatching(revision).getMatchingArtifact(this);
+
+        return getTreeSize() != match.getTreeSize() || Artifacts.bfsStream(self()).anyMatch(a -> {
+            return !a.hasMatching(revision) || !a.getMatching(revision).getMatchingArtifact(a).hashId().equals(a.hashId());
+        });
+    }
+}

bin/tests/scenarios/jdime_matching_issue/left.java

@@ -0,0 +1,22 @@
+package de.fosd.jdime.artifact;
+
+import java.security.MessageDigest;
+
+public abstract class Artifact<T extends Artifact<T>> implements Comparable<T>, StatisticsInterface {
+    public boolean hasChanges(Revision revision) {
+
+        if (this.revision.equals(revision)) {
+            return false;
+        }
+
+        if (!hasMatching(revision)) {
+            return true;
+        }
+
+        T match = getMatching(revision).getMatchingArtifact(this);
+
+        return getTreeSize() != match.getTreeSize() || Artifacts.bfsStream(self()).anyMatch(a -> {
+            return !a.hasMatching(revision) || !a.getMatching(revision).getMatchingArtifact(a).hashId().equals(a.hashId());
+        });
+    }
+}

bin/tests/scenarios/jdime_matching_issue/merge.java

@@ -0,0 +1 @@
+  package    de . fosd . jdime . artifact ;  import   java . security . MessageDigest ;   public abstract class Artifact  <  T  extends  Artifact  < T > >  implements   Comparable  < T > , StatisticsInterface  {   public boolean hasChanges  (  Revision revision )  {  if  (   this . revision . equals  ( revision ) )  {  return false ; }  if  (  !  hasMatching  ( revision ) )  {  return true ; }  T  match =   getMatching  ( revision ) . getMatchingArtifact  ( this ) ;  return    getTreeSize  ( ) !=  match . getTreeSize  ( ) ||  !   getTreeHash  ( ) . equals  (  match . getTreeHash  ( ) ) ; } }

bin/tests/scenarios/jdime_matching_issue/right.java

@@ -0,0 +1,20 @@
+package de.fosd.jdime.artifact;
+
+import java.security.MessageDigest;
+
+public abstract class Artifact<T extends Artifact<T>> implements Comparable<T>, StatisticsInterface {
+    public boolean hasChanges(Revision revision) {
+
+        if (this.revision.equals(revision)) {
+            return false;
+        }
+
+        if (!hasMatching(revision)) {
+            return true;
+        }
+
+        T match = getMatching(revision).getMatchingArtifact(this);
+
+        return getTreeSize() != match.getTreeSize() || !getTreeHash().equals(match.getTreeHash());
+    }
+}

matching/src/ordered_tree_matching.rs

@@ -38,6 +38,14 @@
         ) => {
             let root_matching: usize = (kind_left == kind_right).into();
 
+            // Node kinds do not match, so we return a matching with a score of 0
+            if root_matching == 0 {
+                return Matchings::from_single(
+                    UnorderedPair(left, right),
+                    MatchingEntry::new(0, false),
+                );
+            }
+
             let m = children_left.len();
             let n = children_right.len();
 
@@ -105,9 +113,9 @@
 
 #[cfg(test)]
 mod tests {
     use crate::{matching_entry::MatchingEntry, *};
     use model::{
         cst_node::{NonTerminal, Terminal},
         language, CSTNode, Point,
     };