Extend test for OSGi manifest attributes

gson/pom.xml

@@ -69,6 +69,12 @@
       <version>33.3.0-jre</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+      <version>33.2.1-jre</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
   <build>
@@ -173,6 +179,19 @@
           <argLine>--illegal-access=deny</argLine>
         </configuration>
       </plugin>
+      <!-- Failsafe plugin for running integration tests against final JAR, see `*IT.java` test classes -->
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-failsafe-plugin</artifactId>
+        <executions>
+          <execution>
+            <goals>
+              <goal>integration-test</goal>
+              <goal>verify</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
       <plugin>
         <groupId>com.coderplus.maven.plugins</groupId>
         <artifactId>copy-rename-maven-plugin</artifactId>
@@ -271,7 +290,7 @@
         <artifactId>maven-jar-plugin</artifactId>
         <configuration>
           <archive>
-            <!-- Use existing manifest generated by BND plugin -->
+            <!-- Use existing manifest generated by bnd-maven-plugin -->
             <manifestFile>${project.build.outputDirectory}/META-INF/MANIFEST.MF</manifestFile>
           </archive>
         </configuration>

gson/src/test/java/com/google/gson/integration/OSGiManifestIT.java

@@ -0,0 +1,238 @@
+/*
+ * Copyright (C) 2024 Google Inc.
+ *
+ * Licensed 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 com.google.gson.integration;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.Truth.assertWithMessage;
+import static org.junit.Assert.fail;
+
+import com.google.common.base.Splitter;
+import com.google.gson.internal.GsonBuildConfig;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.jar.Attributes;
+import java.util.jar.Manifest;
+import java.util.stream.Collectors;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Performs assertions on the generated OSGi manifest attributes. This is an integration test
+ * ({@code *IT.java}) intended to be run against the final JAR.
+ *
+ * <p>Note: These tests must be run on the command line with {@code mvn clean verify}, running them
+ * in the IDE will not work because it won't use the generated JAR, and additionally the
+ * bnd-maven-plugin seems to behave differently in the IDE (at least Eclipse), adding unexpected
+ * {@code Import-Package} entries for JDK classes (<a
+ * href="https://github.com/bndtools/bnd/issues/6258>bnd-maven-plugin issue</a>).<br>
+ * Running Maven's {@code clean} phase is necessary due to a <a
+ * href="https://github.com/bndtools/bnd/issues/6221">bnd-maven-plugin bug</a>.
+ */
+public class OSGiManifestIT {
+  private static class ManifestData {
+    public final URL url;
+    public final Manifest manifest;
+
+    public ManifestData(URL url, Manifest manifest) {
+      this.url = url;
+      this.manifest = manifest;
+    }
+  }
+
+  private static final String GSON_VERSION = GsonBuildConfig.VERSION;
+  private Attributes manifestAttributes;
+
+  @Before
+  public void getGsonManifestAttributes() throws Exception {
+    ManifestData manifestData = findManifest("com.google.gson");
+    // Make sure manifest was loaded from final Gson JAR (and not intermediate manifest is used)
+    assertWithMessage(
+            "Should load manifest from Gson JAR file; run this test with `mvn clean verify` on"
+                + " command line and not from IDE")
+        .that(manifestData.url.toString())
+        .endsWith(".jar!/META-INF/MANIFEST.MF");
+
+    manifestAttributes = manifestData.manifest.getMainAttributes();
+  }
+
+  private String getAttribute(String name) {
+    return manifestAttributes.getValue(name);
+  }
+
+  @Test
+  public void testBundleInformation() {
+    assertThat(getAttribute("Bundle-SymbolicName")).isEqualTo("com.google.gson");
+    assertThat(getAttribute("Bundle-Name")).isEqualTo("Gson");
+    assertThat(getAttribute("Bundle-License"))
+        .isEqualTo("\"Apache-2.0\";link=\"https://www.apache.org/licenses/LICENSE-2.0.txt\"");
+    assertThat(getAttribute("Bundle-Version"))
+        .isEqualTo(GSON_VERSION.replace("-SNAPSHOT", ".SNAPSHOT"));
+  }
+
+  @Test
+  public void testImports() throws Exception {
+    // Keep only 'major.minor', drop the 'patch' version
+    String errorProneVersion =
+        shortenVersionNumber(
+            findManifest("com.google.errorprone.annotations")
+                .manifest
+                .getMainAttributes()
+                .getValue("Bundle-Version"),
+            1);
+    String nextMajorErrorProneVersion = increaseVersionNumber(errorProneVersion, 0);
+    String errorProneVersionRange =
+        "[" + errorProneVersion + "," + nextMajorErrorProneVersion + ")";
+
+    List<String> imports = splitPackages(getAttribute("Import-Package"));
+    // If imports contains `java.*`, then either user started from IDE, or IDE rebuilt project while
+    // Maven build was running, see https://github.com/bndtools/bnd/issues/6258
+    if (imports.stream().anyMatch(i -> i.startsWith("java."))) {
+      fail(
+          "Test must be run from command line with `mvn clean verify`; additionally make sure your"
+              + " IDE did not rebuild the project in the meantime");
+    }
+
+    assertThat(imports)
+        .containsExactly(
+            // Dependency on JDK's sun.misc.Unsafe should be optional
+            "sun.misc;resolution:=optional",
+            "com.google.errorprone.annotations;version=\"" + errorProneVersionRange + "\"");
+
+    // Should not contain any import for Gson's own packages, see
+    // https://github.com/google/gson/pull/2735#issuecomment-2330047410
+    for (String importedPackage : imports) {
+      assertThat(importedPackage).doesNotContain("com.google.gson");
+    }
+  }
+
+  @Test
+  public void testExports() {
+    String gsonVersion = GSON_VERSION.replace("-SNAPSHOT", "");
+
+    List<String> exports = splitPackages(getAttribute("Export-Package"));
+    // When not running `mvn clean` the exports might differ slightly, see
+    // https://github.com/bndtools/bnd/issues/6221
+    assertWithMessage("Unexpected exports; make sure you are running `mvn clean ...`")
+        .that(exports)
+        // Note: This just represents the currently generated exports; especially the `uses` can be
+        // adjusted if necessary when Gson's implementation changes
+        .containsExactly(
+            "com.google.gson;uses:=\"com.google.gson.reflect,com.google.gson.stream\";version=\""
+                + gsonVersion
+                + "\"",
+            "com.google.gson.annotations;version=\"" + gsonVersion + "\"",
+            "com.google.gson.reflect;version=\"" + gsonVersion + "\"",
+            "com.google.gson.stream;uses:=\"com.google.gson\";version=\"" + gsonVersion + "\"");
+  }
+
+  @Test
+  public void testRequireCapability() {
+    // When building with JDK >= 21, the minimum target version is Java 8
+    String expectedJavaVersion = Runtime.version().feature() < 21 ? "1.7" : "1.8";
+
+    // Defines the minimum required Java version
+    assertThat(getAttribute("Require-Capability"))
+        .isEqualTo("osgi.ee;filter:=\"(&(osgi.ee=JavaSE)(version=" + expectedJavaVersion + "))\"");
+
+    // Should not define deprecated "Bundle-RequiredExecutionEnvironment"
+    assertThat(getAttribute("Bundle-RequiredExecutionEnvironment")).isNull();
+  }
+
+  private ManifestData findManifest(String bundleName) throws IOException {
+    List<URL> manifestResources =
+        Collections.list(getClass().getClassLoader().getResources("META-INF/MANIFEST.MF"));
+
+    for (URL manifestResource : manifestResources) {
+      Manifest manifest;
+      try (InputStream is = manifestResource.openStream()) {
+        manifest = new Manifest(is);
+      }
+      if (bundleName.equals(manifest.getMainAttributes().getValue("Bundle-SymbolicName"))) {
+        return new ManifestData(manifestResource, manifest);
+      }
+    }
+
+    fail(
+        "Cannot find "
+            + bundleName
+            + " OSGi bundle manifest among: "
+            + manifestResources
+            + "\nRun this test with `mvn clean verify` on command line and not from the IDE.");
+    return null;
+  }
+
+  /** Splits a list of packages separated by {@code ','}. */
+  private List<String> splitPackages(String packagesString) {
+    List<String> splitPackages = new ArrayList<>();
+    int nextSplitStart = 0;
+    boolean isInQuotes = false;
+
+    for (int i = 0; i < packagesString.length(); i++) {
+      char c = packagesString.charAt(i);
+      // Ignore ',' inside quotes
+      if (c == '"') {
+        isInQuotes = !isInQuotes;
+      } else if (c == ',' && !isInQuotes) {
+        splitPackages.add(packagesString.substring(nextSplitStart, i));
+        nextSplitStart = i + 1; // skip past the ','
+      }
+    }
+
+    // Add package behind last ','
+    splitPackages.add(packagesString.substring(nextSplitStart));
+    return splitPackages;
+  }
+
+  /**
+   * Shortens a version number by dropping lower parts. For example {@code 1.2.3 -> 1.2} (when
+   * {@code keepPosition = 1}).
+   *
+   * @param versionString e.g. "1.2.3"
+   * @param keepPosition position of the version to keep: 0 = major, 1 = minor, ...
+   * @return shortened version number
+   */
+  private String shortenVersionNumber(String versionString, int keepPosition) {
+    return Splitter.on('.')
+        .splitToStream(versionString)
+        .limit(keepPosition + 1)
+        .collect(Collectors.joining("."));
+  }
+
+  /**
+   * Increases part of a version number (and drops lower parts). For example {@code 1.2.3 -> 1.3}
+   * (when {@code position = 1}).
+   *
+   * @param versionString e.g. "1.2.3"
+   * @param position position of the version to increase: 0 = major, 1 = minor, ...
+   * @return increased version number
+   */
+  private String increaseVersionNumber(String versionString, int position) {
+    List<Integer> splitVersion = new ArrayList<>();
+    for (String versionPiece : Splitter.on('.').split(versionString)) {
+      splitVersion.add(Integer.valueOf(versionPiece));
+    }
+    // Drop lower version parts
+    splitVersion = splitVersion.subList(0, position + 1);
+    // Increase version number
+    splitVersion.set(position, splitVersion.get(position) + 1);
+
+    return splitVersion.stream().map(i -> i.toString()).collect(Collectors.joining("."));
+  }
+}

pom.xml

@@ -339,7 +339,12 @@
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-surefire-plugin</artifactId>
           <version>3.5.0</version>
-          </plugin>
+        </plugin>
+        <plugin>
+          <groupId>org.apache.maven.plugins</groupId>
+          <artifactId>maven-failsafe-plugin</artifactId>
+          <version>3.5.0</version>
+        </plugin>
         <plugin>
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-jar-plugin</artifactId>
@@ -542,9 +547,9 @@
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-compiler-plugin</artifactId>
             <configuration>
-             <compilerArgs combine.self="override">
-               <compilerArg>-Xlint:all,-options</compilerArg>
-             </compilerArgs>
+              <compilerArgs combine.self="override">
+                <compilerArg>-Xlint:all,-options</compilerArg>
+              </compilerArgs>
             </configuration>
           </plugin>
         </plugins>