fix: protobuf version not always getting set in headers

gax-java/gax/src/main/java/com/google/api/gax/core/GaxProperties.java

@@ -30,6 +30,7 @@
 package com.google.api.gax.core;
 
 import com.google.api.core.InternalApi;
+import com.google.api.gax.util.ClassWrapper;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Strings;
 import com.google.protobuf.Any;
@@ -48,8 +49,7 @@ public class GaxProperties {
   private static final String DEFAULT_VERSION = "";
   private static final String GAX_VERSION = getLibraryVersion(GaxProperties.class, "version.gax");
   private static final String JAVA_VERSION = getRuntimeVersion();
-  private static final String PROTOBUF_VERSION =
-      getBundleVersion(Any.class).orElse(DEFAULT_VERSION);
+  private static final String PROTOBUF_VERSION = getProtobufVersion(new ClassWrapper(), Any.class);
 
   private GaxProperties() {}
 
@@ -148,4 +148,30 @@ static Optional<String> getBundleVersion(Class<?> clazz) {
       return Optional.empty();
     }
   }
+
+  /**
+   * Returns the Protobuf runtime version as reported by com.google.protobuf.RuntimeVersion, if
+   * class is available, otherwise by reading from MANIFEST file. If niether option is available
+   * defaults to protobuf version 3 as RuntimeVersion class is available in protobuf version 4+
+   */
+  @VisibleForTesting
+  static String getProtobufVersion(ClassWrapper classWrapper, Class clazz) {
+    try {
+      Class<?> protobufRuntimeVersionClass =
+          classWrapper.forName("com.google.protobuf.RuntimeVersion");
+      return classWrapper.getFieldValue(protobufRuntimeVersionClass, "MAJOR")
+          + "."
+          + classWrapper.getFieldValue(protobufRuntimeVersionClass, "MINOR")
+          + "."
+          + classWrapper.getFieldValue(protobufRuntimeVersionClass, "PATCH");
+    } catch (ClassNotFoundException
+        | NoSuchFieldException
+        | IllegalAccessException
+        | SecurityException e) {
+      // If manifest file is not available default to protobuf generic version 3 as we know
+      // RuntimeVersion class is
+      // available in protobuf jar 4+.
+      return getBundleVersion(clazz).orElse("3");
+    }
+  }
 }

gax-java/gax/src/main/java/com/google/api/gax/rpc/ApiClientHeaderProvider.java

@@ -88,7 +88,7 @@ private static String checkAndAppendProtobufVersionIfNecessary(
     // TODO(b/366417603): appending protobuf version to existing client library token until resolved
     Pattern pattern = Pattern.compile("(gccl|gapic)\\S*");
     Matcher matcher = pattern.matcher(apiClientHeaderValue);
-    if (matcher.find()) {
+    if (matcher.find() && GaxProperties.getProtobufVersion() != null) {
       return apiClientHeaderValue.substring(0, matcher.end())
           + "--"
           + PROTOBUF_HEADER_VERSION_KEY

gax-java/gax/src/main/java/com/google/api/gax/util/ClassWrapper.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google LLC nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package com.google.api.gax.util;
+
+/* Wrapper class for reflection {@link java.lang.Class} methods to enable unit testing. */
+public class ClassWrapper {
+
+  /* Wraps {@link java.lang.Class#forName} method  */
+  public Class<?> forName(String name) throws ClassNotFoundException {
+    return Class.forName(name);
+  }
+
+  /* Consolidates retrieving a {@link java.lang.Field} on a {@link java.lang.Class} object via reflection and retrieving the value of that Field */
+  public Object getFieldValue(Class<?> clazz, String fieldName)
+      throws NoSuchFieldException, IllegalAccessException {
+    return clazz.getField(fieldName).get(null);
+  }
+}

gax-java/gax/src/main/resources/META-INF/native-image/com.google.api/gax/reflect-config.json

@@ -0,0 +1,10 @@
+[
+  {
+    "name": "com.google.protobuf.RuntimeVersion",
+    "fields" : [
+      { "name" : "MAJOR" },
+      { "name" : "MINOR" },
+      { "name" : "PATCH" }
+    ]
+  }
+]

gax-java/gax/src/test/java/com/google/api/gax/core/GaxPropertiesTest.java

@@ -33,8 +33,13 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
+import com.google.api.gax.util.ClassWrapper;
 import com.google.common.base.Strings;
+import com.google.protobuf.Any;
 import java.io.IOException;
 import java.util.Optional;
 import java.util.regex.Pattern;
@@ -160,12 +165,8 @@ void testGetJavaRuntimeInfo_nullJavaVersion() {
 
   @Test
   public void testGetProtobufVersion() throws IOException {
-    Version version = readVersion(GaxProperties.getProtobufVersion());
-
-    assertTrue(version.major >= 3);
-    if (version.major == 3) {
-      assertTrue(version.minor >= 25);
-    }
+    assertTrue(
+        Pattern.compile("^\\d+\\.\\d+\\.\\d+").matcher(GaxProperties.getProtobufVersion()).find());
   }
 
   @Test
@@ -175,6 +176,52 @@ public void testGetBundleVersion_noManifestFile() throws IOException {
     assertFalse(version.isPresent());
   }
 
+  @Test
+  void testGetProtobufVersion_success() throws Exception {
+    ClassWrapper mockClassWrapper = mock(ClassWrapper.class);
+    when(mockClassWrapper.forName("com.google.protobuf.RuntimeVersion"))
+        .thenAnswer(invocationOnMock -> Class.class);
+    when(mockClassWrapper.getFieldValue(Class.class, "MAJOR")).thenReturn("2");
+    when(mockClassWrapper.getFieldValue(Class.class, "MINOR")).thenReturn("3");
+    when(mockClassWrapper.getFieldValue(Class.class, "PATCH")).thenReturn("4");
+
+    String version = GaxProperties.getProtobufVersion(mockClassWrapper, Any.class);
+
+    assertEquals("2.3.4", version);
+  }
+
+  @Test
+  void testGetProtobufVersion_classNotFoundException() throws Exception {
+    ClassWrapper mockClassWrapper = mock(ClassWrapper.class);
+    when(mockClassWrapper.forName("com.google.protobuf.RuntimeVersion"))
+        .thenThrow(new ClassNotFoundException(""));
+
+    String version = GaxProperties.getProtobufVersion(mockClassWrapper, Any.class);
+
+    assertTrue(Pattern.compile("^\\d+\\.\\d+\\.\\d+").matcher(version).find());
+  }
+
+  @Test
+  void testgetProtobufVersion_noSuchFieldException() throws Exception {
+    ClassWrapper mockClassWrapper = mock(ClassWrapper.class);
+    when(mockClassWrapper.getFieldValue(any(), any())).thenThrow(NoSuchFieldException.class);
+
+    String version = GaxProperties.getProtobufVersion(mockClassWrapper, Any.class);
+
+    assertTrue(Pattern.compile("^\\d+\\.\\d+\\.\\d+").matcher(version).find());
+  }
+
+  @Test
+  void testGetProtobufVersion_noManifest() throws Exception {
+    ClassWrapper mockClassWrapper = mock(ClassWrapper.class);
+    when(mockClassWrapper.forName("com.google.protobuf.RuntimeVersion"))
+        .thenThrow(new ClassNotFoundException(""));
+
+    String version = GaxProperties.getProtobufVersion(mockClassWrapper, GaxProperties.class);
+
+    assertEquals("3", version);
+  }
+
   private Version readVersion(String version) {
     assertTrue(Pattern.compile("^\\d+\\.\\d+\\.\\d+").matcher(version).find());
     String[] versionComponents = version.split("\\.");

showcase/gapic-showcase/src/test/java/com/google/showcase/v1beta1/it/ITVersionHeaders.java

@@ -241,7 +241,7 @@ void testHttpJsonCompliance_userApiVersionSetSuccess() throws IOException {
   @Test
   void testGrpcCall_sendsCorrectApiClientHeader() {
     Pattern defautlGrpcHeaderPattern =
-        Pattern.compile("gl-java/.* gapic/.*?--protobuf-.* gax/.* grpc/.* protobuf/.*");
+        Pattern.compile("gl-java/.* gapic/.*?--protobuf-\\d.* gax/.* grpc/.* protobuf/\\d.*");
     grpcClient.echo(EchoRequest.newBuilder().build());
     String headerValue = grpcInterceptor.metadata.get(API_CLIENT_HEADER_KEY);
     assertTrue(defautlGrpcHeaderPattern.matcher(headerValue).matches());
@@ -250,7 +250,7 @@ void testGrpcCall_sendsCorrectApiClientHeader() {
   @Test
   void testHttpJson_sendsCorrectApiClientHeader() {
     Pattern defautlHttpHeaderPattern =
-        Pattern.compile("gl-java/.* gapic/.*?--protobuf-.* gax/.* rest/ protobuf/.*");
+        Pattern.compile("gl-java/.* gapic/.*?--protobuf-\\d.* gax/.* rest/ protobuf/\\d.*");
     httpJsonClient.echo(EchoRequest.newBuilder().build());
     ArrayList<String> headerValues =
         (ArrayList<String>)