Restore augmentation sorting semantics

Augmentation sort we are performing to order augmentations has another,
undocumented, impact. It provides stability of generated code towards
reformats of the YANG source, so that changing the order of augment
statements (by itself) does not change the naming of generated fields.

The simple comparator failed to take this effect, leading to an
incompatible change of assignments which is extremely hard to untangle.
Fix this by restoring previous sorting behaviour.

Change-Id: I7164e6e06d47fcded3261752a8a0f587afc70274
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>

diff --git a/binding/mdsal-binding-generator-impl/src/main/java/org/opendaylight/mdsal/binding/generator/impl/reactor/AbstractAugmentGenerator.java b/binding/mdsal-binding-generator-impl/src/main/java/org/opendaylight/mdsal/binding/generator/impl/reactor/AbstractAugmentGenerator.java
index 88824b73305a4a466abbaf0a83ec316286ac14fa..114dbfc72a9c5a1be8501fd2727f87cde9dfca61 100644 (file)
--- a/binding/mdsal-binding-generator-impl/src/main/java/org/opendaylight/mdsal/binding/generator/impl/reactor/AbstractAugmentGenerator.java
+++ b/binding/mdsal-binding-generator-impl/src/main/java/org/opendaylight/mdsal/binding/generator/impl/reactor/AbstractAugmentGenerator.java
@@ -11,6 +11,7 @@ import static com.google.common.base.Verify.verify;
 import static com.google.common.base.Verify.verifyNotNull;
 
 import java.util.Comparator;
+import java.util.Iterator;
 import org.eclipse.jdt.annotation.NonNull;
 import org.opendaylight.mdsal.binding.generator.impl.reactor.CollisionDomain.Member;
 import org.opendaylight.mdsal.binding.model.api.GeneratedType;
@@ -19,6 +20,7 @@ import org.opendaylight.mdsal.binding.model.api.type.builder.GeneratedTypeBuilde
 import org.opendaylight.mdsal.binding.model.util.BindingTypes;
 import org.opendaylight.yangtools.odlext.model.api.AugmentIdentifierEffectiveStatement;
 import org.opendaylight.yangtools.yang.common.AbstractQName;
+import org.opendaylight.yangtools.yang.common.QName;
 import org.opendaylight.yangtools.yang.model.api.stmt.AugmentEffectiveStatement;
 import org.opendaylight.yangtools.yang.model.util.SchemaInferenceStack;
 
@@ -50,9 +52,30 @@ abstract class AbstractAugmentGenerator extends AbstractCompositeGenerator<Augme
      * <p>
      * Evaluating these in the order of increasing argument component count solves this without having to perform a full
      * analysis.
+     *
+     * <p>
+     * Another problem we are solving here is augmentation target stability, as the declared order in YANG text may
+     * change, which does not really change the semantics. If we only relied on length of argument, such a move would
+     * result in changing the results of {@link #createMember(CollisionDomain)} and make upgrades rather unpredictable.
+     * We solve this by using {@link QName#compareTo(QName)} to determine order.
      */
-    static final Comparator<? super AbstractAugmentGenerator> COMPARATOR =
-        Comparator.comparingInt(augment -> augment.statement().argument().getNodeIdentifiers().size());
+    static final Comparator<? super AbstractAugmentGenerator> COMPARATOR = (o1, o2) -> {
+        final Iterator<QName> thisIt = o1.statement().argument().getNodeIdentifiers().iterator();
+        final Iterator<QName> otherIt = o2.statement().argument().getNodeIdentifiers().iterator();
+
+        while (thisIt.hasNext()) {
+            if (!otherIt.hasNext()) {
+                return 1;
+            }
+
+            final int comp = thisIt.next().compareTo(otherIt.next());
+            if (comp != 0) {
+                return comp;
+            }
+        }
+
+        return otherIt.hasNext() ? -1 : 0;
+    };
 
     private AbstractCompositeGenerator<?> targetGen;
 
@@ -138,5 +161,4 @@ abstract class AbstractAugmentGenerator extends AbstractCompositeGenerator<Augme
     }
 
     abstract void loadTargetGenerator();
-
 }