Improve TestBuildInfoPluginFuncTest (elastic#128322)

* Use walkFileTree for extractModuleNameFromDirectory

* More tests in TestBuildInfoPluginFuncTest

* Remove stray line from debugging

* [CI] Auto commit changes from spotless

* Eliminate List.reversed() call

---------

Co-authored-by: elasticsearchmachine <[email protected]>

Author: prdoyle

build-tools/src/integTest/groovy/org/elasticsearch/gradle/test/TestBuildInfoPluginFuncTest.groovy

@@ -6,7 +6,7 @@ import org.elasticsearch.gradle.fixtures.AbstractGradleFuncTest
 import org.gradle.testkit.runner.TaskOutcome
 
 class TestBuildInfoPluginFuncTest extends AbstractGradleFuncTest {
-    def "works"() {
+    def "basic functionality"() {
         given:
         file("src/main/java/com/example/Example.java") << """
             package com.example;
@@ -60,4 +60,62 @@ class TestBuildInfoPluginFuncTest extends AbstractGradleFuncTest {
         )
         new ObjectMapper().readValue(output, Map.class) == expectedOutput
     }
+
+    def "dependencies"() {
+        buildFile << """
+        import org.elasticsearch.gradle.plugin.GenerateTestBuildInfoTask;
+
+        plugins {
+            id 'java'
+            id 'elasticsearch.test-build-info'
+        }
+
+        repositories {
+            mavenCentral()
+        }
+
+        dependencies {
+            // We pin to specific versions here because they are known to have the properties we want to test.
+            // We're not actually running this code.
+            implementation "org.ow2.asm:asm:9.7.1" // has module-info.class
+            implementation "junit:junit:4.13" // has Automatic-Module-Name, and brings in hamcrest which does not
+        }
+
+        tasks.withType(GenerateTestBuildInfoTask.class) {
+            componentName = 'example-component'
+            outputFile = new File('build/generated-build-info/plugin-test-build-info.json')
+        }
+        """
+
+        when:
+        def result = gradleRunner('generateTestBuildInfo').build()
+        def task = result.task(":generateTestBuildInfo")
+
+
+        then:
+        task.outcome == TaskOutcome.SUCCESS
+
+        def output = file("build/generated-build-info/plugin-test-build-info.json")
+        output.exists() == true
+
+        def locationFromModuleInfo = Map.of(
+            "module", "org.objectweb.asm",
+            "representative_class", 'org/objectweb/asm/AnnotationVisitor.class'
+        )
+        def locationFromManifest = Map.of(
+            "module", "junit",
+            "representative_class", 'junit/textui/TestRunner.class'
+        )
+        def locationFromJarFileName = Map.of(
+            "module", "hamcrest.core",
+            "representative_class", 'org/hamcrest/BaseDescription.class'
+        )
+        def expectedOutput = Map.of(
+            "component", "example-component",
+            "locations", List.of(locationFromModuleInfo, locationFromManifest, locationFromJarFileName)
+        )
+
+        def value = new ObjectMapper().readValue(output, Map.class)
+        value == expectedOutput
+    }
 }

build-tools/src/main/java/org/elasticsearch/gradle/plugin/GenerateTestBuildInfoTask.java

@@ -41,7 +41,7 @@
 import java.nio.file.attribute.BasicFileAttributes;
 import java.security.CodeSource;
 import java.util.ArrayList;
-import java.util.Arrays;
+import java.util.Comparator;
 import java.util.List;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
@@ -209,17 +209,16 @@ private String extractModuleNameFromJar(File file, JarFile jarFile) throws IOExc
      * @return a {@link StringBuilder} with the {@code META-INF/versions/<version number>} if it exists; otherwise null
      */
     private static StringBuilder versionDirectoryIfExists(JarFile jarFile) {
+        Comparator<Integer> numericOrder = Integer::compareTo;
         List<Integer> versions = jarFile.stream()
             .filter(je -> je.getName().startsWith(META_INF_VERSIONS_PREFIX) && je.getName().endsWith("/module-info.class"))
             .map(
                 je -> Integer.parseInt(
                     je.getName().substring(META_INF_VERSIONS_PREFIX.length(), je.getName().length() - META_INF_VERSIONS_PREFIX.length())
                 )
             )
+            .sorted(numericOrder.reversed())
             .toList();
-        versions = new ArrayList<>(versions);
-        versions.sort(Integer::compareTo);
-        versions = versions.reversed();
         int major = Runtime.version().feature();
         StringBuilder path = new StringBuilder(META_INF_VERSIONS_PREFIX);
         for (int version : versions) {
@@ -300,7 +299,10 @@ private String extractClassNameFromDirectory(File dir) throws IOException {
             public @NotNull FileVisitResult visitFile(@NotNull Path candidate, @NotNull BasicFileAttributes attrs) {
                 String name = candidate.getFileName().toString(); // Just the part after the last dir separator
                 if (name.endsWith(".class") && (name.equals("module-info.class") || name.contains("$")) == false) {
-                    result = candidate.toAbsolutePath().toString().substring(dir.getAbsolutePath().length() + 1);
+                    result = candidate.toAbsolutePath()
+                        .toString()
+                        .substring(dir.getAbsolutePath().length() + 1)
+                        .replace(File.separatorChar, '/');
                     return TERMINATE;
                 } else {
                     return CONTINUE;
@@ -316,20 +318,24 @@ private String extractClassNameFromDirectory(File dir) throws IOException {
      * if it exists or the preset one derived from the jar task
      */
     private String extractModuleNameFromDirectory(File dir) throws IOException {
-        List<File> files = new ArrayList<>(List.of(dir));
-        while (files.isEmpty() == false) {
-            File find = files.removeFirst();
-            if (find.exists()) {
-                if (find.getName().equals("module-info.class")) {
-                    try (InputStream inputStream = new FileInputStream(find)) {
-                        return extractModuleNameFromModuleInfo(inputStream);
+        var visitor = new SimpleFileVisitor<Path>() {
+            private String result = getModuleName().getOrNull();
+
+            @Override
+            public @NotNull FileVisitResult visitFile(@NotNull Path candidate, @NotNull BasicFileAttributes attrs) throws IOException {
+                String name = candidate.getFileName().toString(); // Just the part after the last dir separator
+                if (name.equals("module-info.class")) {
+                    try (InputStream inputStream = new FileInputStream(candidate.toFile())) {
+                        result = extractModuleNameFromModuleInfo(inputStream);
+                        return TERMINATE;
                     }
-                } else if (find.isDirectory()) {
-                    files.addAll(Arrays.asList(find.listFiles()));
+                } else {
+                    return CONTINUE;
                 }
             }
-        }
-        return getModuleName().getOrNull();
+        };
+        Files.walkFileTree(dir.toPath(), visitor);
+        return visitor.result;
     }
 
     /**