Anchor VersionMapper to the trailing version segment (#374)

src/main/java/org/apache/maven/ant/tasks/support/VersionMapper.java

@@ -40,16 +40,20 @@ public class VersionMapper implements FileNameMapper, Comparator<String> {
     public String[] mapFileName(String sourceFileName) {
         String originalFileName = new File(sourceFileName).getName();
         for (String version : versions) {
-            int index = originalFileName.indexOf(version);
-            if (index >= 0) {
-                // remove version in artifactId-version(-classifier).type
-                String baseFilename = originalFileName.substring(0, index - 1);
-                String extension = originalFileName.substring(index + version.length());
-                String path = sourceFileName.substring(0, sourceFileName.length() - originalFileName.length());
-                if ("flatten".equals(to)) {
-                    path = "";
+            int index = originalFileName.lastIndexOf('-' + version);
+            while (index >= 0) {
+                // only strip a trailing -<version> segment, followed by the file extension, by a
+                // -<classifier> segment, or by nothing
+                String suffix = originalFileName.substring(index + version.length() + 1);
+                if (suffix.isEmpty() || suffix.startsWith(".") || suffix.startsWith("-")) {
+                    String baseFilename = originalFileName.substring(0, index);
+                    String path = sourceFileName.substring(0, sourceFileName.length() - originalFileName.length());
+                    if ("flatten".equals(to)) {
+                        path = "";
+                    }
+                    return new String[] {path + baseFilename + suffix};
                 }
-                return new String[] {path + baseFilename + extension};
+                index = originalFileName.lastIndexOf('-' + version, index - 1);
             }
         }
         return new String[] {sourceFileName};

src/test/java/org/apache/maven/ant/tasks/support/VersionMapperTest.java

@@ -0,0 +1,105 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.maven.ant.tasks.support;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertArrayEquals;
+
+/**
+ * Test class for {@link VersionMapper}.
+ */
+class VersionMapperTest {
+
+    private VersionMapper mapper;
+
+    @BeforeEach
+    void setUp() {
+        mapper = new VersionMapper();
+        mapper.setTo("flatten");
+    }
+
+    /**
+     * The trailing version segment of the filename is stripped.
+     */
+    @Test
+    void stripsTrailingVersion() {
+        mapper.setFrom("1.0");
+        assertArrayEquals(new String[] {"artifactId.jar"}, mapper.mapFileName("artifactId-1.0.jar"));
+    }
+
+    /**
+     * The version segment before the classifier is stripped, keeping the classifier.
+     */
+    @Test
+    void stripsVersionBeforeClassifier() {
+        mapper.setFrom("1.0");
+        assertArrayEquals(new String[] {"artifactId-jre.jar"}, mapper.mapFileName("artifactId-1.0-jre.jar"));
+    }
+
+    /**
+     * A filename starting with the version must not throw a {@link StringIndexOutOfBoundsException}.
+     */
+    @Test
+    void versionAtStartOfFilenameDoesNotThrow() {
+        mapper.setFrom("1.0");
+        assertArrayEquals(new String[] {"1.0.jar"}, mapper.mapFileName("1.0.jar"));
+    }
+
+    /**
+     * When the version occurs both inside the artifact id and as the trailing version segment, only the trailing
+     * segment is stripped.
+     */
+    @Test
+    void stripsOnlyTrailingOccurrenceOfVersion() {
+        mapper.setFrom("1.0");
+        assertArrayEquals(new String[] {"a-1.0-b.jar"}, mapper.mapFileName("a-1.0-b-1.0.jar"));
+    }
+
+    /**
+     * A version-like substring that is not a trailing segment is left untouched.
+     */
+    @Test
+    void doesNotStripVersionInsideArtifactId() {
+        mapper.setFrom("1.0");
+        assertArrayEquals(new String[] {"a-1.0b.jar"}, mapper.mapFileName("a-1.0b.jar"));
+    }
+
+    /**
+     * The directory part of the filename is preserved unless the mapper is configured to flatten.
+     */
+    @Test
+    void preservesDirectoryPart() {
+        mapper.setFrom("1.0");
+        mapper.setTo(null);
+        assertArrayEquals(
+                new String[] {"directory" + java.io.File.separator + "artifactId.jar"},
+                mapper.mapFileName("directory" + java.io.File.separator + "artifactId-1.0.jar"));
+    }
+
+    /**
+     * A filename without any configured version is returned unchanged.
+     */
+    @Test
+    void returnsUnchangedWhenNoVersionMatches() {
+        mapper.setFrom("9.9");
+        assertArrayEquals(new String[] {"artifactId-1.0.jar"}, mapper.mapFileName("artifactId-1.0.jar"));
+    }
+}