Ensure packages and classes are traversed in order.

This ensures the generated JSON is stable over regeneration to minimize
diffs.

1 files changed, 11 insertions, 2 deletions

diff --git a/abi-check-plugin/src/main/java/com/yahoo/abicheck/mojo/AbiCheck.java b/abi-check-plugin/src/main/java/com/yahoo/abicheck/mojo/AbiCheck.java
index e03f4798b2a..2ee7bd495b3 100644
--- a/abi-check-plugin/src/main/java/com/yahoo/abicheck/mojo/AbiCheck.java
+++ b/abi-check-plugin/src/main/java/com/yahoo/abicheck/mojo/AbiCheck.java
@@ -1,5 +1,6 @@
 package com.yahoo.abicheck.mojo;
 
+import com.google.common.collect.Ordering;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
 import com.google.gson.reflect.TypeToken;
@@ -15,11 +16,14 @@ import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.Comparator;
 import java.util.HashSet;
 import java.util.LinkedHashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.jar.JarFile;
+import java.util.stream.Collectors;
 import org.apache.maven.artifact.Artifact;
 import org.apache.maven.plugin.AbstractMojo;
 import org.apache.maven.plugin.MojoExecutionException;
@@ -132,14 +136,19 @@ public class AbiCheck extends AbstractMojo {
     Map<String, JavaClassSignature> signatures = new LinkedHashMap<>();
     if (isPublicAbiPackage(pkg, publicApiAnnotation)) {
       PublicSignatureCollector collector = new PublicSignatureCollector();
-      for (ClassFile klazz : pkg.getClassFiles()) {
+      List<ClassFileTree.ClassFile> sortedClassFiles = pkg.getClassFiles().stream()
+          .sorted(Comparator.comparing(ClassFile::getName)).collect(Collectors.toList());
+      for (ClassFile klazz : sortedClassFiles) {
         try (InputStream is = klazz.getInputStream()) {
           new ClassReader(is).accept(collector, 0);
         }
       }
       signatures.putAll(collector.getClassSignatures());
     }
-    for (ClassFileTree.Package subPkg : pkg.getSubPackages()) {
+    List<ClassFileTree.Package> sortedSubPackages = pkg.getSubPackages().stream()
+        .sorted(Comparator.comparing(Package::getFullyQualifiedName))
+        .collect(Collectors.toList());
+    for (ClassFileTree.Package subPkg : sortedSubPackages) {
       signatures.putAll(collectPublicAbiSignatures(subPkg, publicApiAnnotation));
     }
     return signatures;