Expose ForwardingRequestBody in the main module

okhttp-testing-support/src/main/kotlin/okhttp3/UppercaseRequestInterceptor.kt

@@ -30,17 +30,15 @@ class UppercaseRequestInterceptor : Interceptor {
 
   /** Returns a request that transforms `request` to be all uppercase.  */
   private fun uppercaseRequest(request: Request): Request {
+    val body = request.body ?: return request
     val uppercaseBody: RequestBody =
-      object : ForwardingRequestBody(request.body) {
+      object : ForwardingRequestBody(delegate = body) {
         @Throws(IOException::class)
         override fun writeTo(sink: BufferedSink) {
           delegate().writeTo(uppercaseSink(sink).buffer())
         }
       }
-    return request
-      .newBuilder()
-      .method(request.method, uppercaseBody)
-      .build()
+    return request.newBuilder().method(request.method, uppercaseBody).build()
   }
 
   private fun uppercaseSink(sink: Sink): Sink =

okhttp/api/android/okhttp.api

@@ -624,6 +624,17 @@ public final class okhttp3/FormBody$Builder {
 public final class okhttp3/FormBody$Companion {
 }
 
+public class okhttp3/ForwardingRequestBody : okhttp3/RequestBody {
+	public fun <init> (Lokhttp3/RequestBody;)V
+	public fun contentLength ()J
+	public fun contentType ()Lokhttp3/MediaType;
+	public final fun delegate ()Lokhttp3/RequestBody;
+	public fun isDuplex ()Z
+	public fun isOneShot ()Z
+	public fun toString ()Ljava/lang/String;
+	public fun writeTo (Lokio/BufferedSink;)V
+}
+
 public final class okhttp3/Gzip : okhttp3/CompressionInterceptor$DecompressionAlgorithm {
 	public static final field INSTANCE Lokhttp3/Gzip;
 	public fun decompress (Lokio/BufferedSource;)Lokio/Source;

okhttp/api/jvm/okhttp.api

@@ -624,6 +624,17 @@ public final class okhttp3/FormBody$Builder {
 public final class okhttp3/FormBody$Companion {
 }
 
+public class okhttp3/ForwardingRequestBody : okhttp3/RequestBody {
+	public fun <init> (Lokhttp3/RequestBody;)V
+	public fun contentLength ()J
+	public fun contentType ()Lokhttp3/MediaType;
+	public final fun delegate ()Lokhttp3/RequestBody;
+	public fun isDuplex ()Z
+	public fun isOneShot ()Z
+	public fun toString ()Ljava/lang/String;
+	public fun writeTo (Lokio/BufferedSink;)V
+}
+
 public final class okhttp3/Gzip : okhttp3/CompressionInterceptor$DecompressionAlgorithm {
 	public static final field INSTANCE Lokhttp3/Gzip;
 	public fun decompress (Lokio/BufferedSource;)Lokio/Source;

okhttp-testing-support/src/main/kotlin/okhttp3/ForwardingRequestBody.kt → okhttp/src/commonJvmAndroid/kotlin/okhttp3/ForwardingRequestBody.kt

@@ -19,10 +19,8 @@ import java.io.IOException
 import okio.BufferedSink
 
 open class ForwardingRequestBody(
-  delegate: RequestBody?,
+  private val delegate: RequestBody,
 ) : RequestBody() {
-  private val delegate: RequestBody
-
   fun delegate(): RequestBody = delegate
 
   override fun contentType(): MediaType? = delegate.contentType()
@@ -37,10 +35,7 @@ open class ForwardingRequestBody(
 
   override fun isDuplex(): Boolean = delegate.isDuplex()
 
-  override fun toString(): String = javaClass.simpleName + "(" + delegate.toString() + ")"
+  override fun isOneShot(): Boolean = delegate.isOneShot()
 
-  init {
-    requireNotNull(delegate) { "delegate == null" }
-    this.delegate = delegate
-  }
+  override fun toString(): String = javaClass.simpleName + "(" + delegate.toString() + ")"
 }

okhttp/src/jvmTest/kotlin/okhttp3/ForwardingRequestBodyTest.kt

@@ -0,0 +1,78 @@
+package okhttp3
+
+import assertk.assertThat
+import assertk.assertions.isEqualTo
+import okhttp3.MediaType.Companion.toMediaType
+import okhttp3.RequestBody.Companion.toRequestBody
+import okio.Buffer
+import okio.BufferedSink
+import org.junit.jupiter.params.ParameterizedTest
+import org.junit.jupiter.params.provider.CsvSource
+import org.junit.jupiter.params.provider.NullSource
+import org.junit.jupiter.params.provider.ValueSource
+
+open class ForwardingRequestBodyTest {
+  /**
+   * Verifies that overriding the content type preserves the delegate's content,
+   * content length, and one-shot and duplex flags.
+   */
+  @ParameterizedTest
+  @CsvSource(
+    "false, false",
+    "false, true",
+    "true, false",
+    "true, true",
+  )
+  fun overridingContentTypePreservesBodyBehavior(
+    oneShot: Boolean,
+    duplex: Boolean,
+  ) {
+    val originalType = "text/plain".toMediaType()
+    val overriddenType = "application/octet-stream".toMediaType()
+
+    val delegate =
+      object : RequestBody() {
+        override fun contentType(): MediaType = originalType
+
+        override fun contentLength(): Long = 5L
+
+        override fun writeTo(sink: BufferedSink) {
+          sink.writeUtf8("hello")
+        }
+
+        override fun isOneShot(): Boolean = oneShot
+
+        override fun isDuplex(): Boolean = duplex
+      }
+
+    val forwardingBody =
+      object : ForwardingRequestBody(delegate) {
+        override fun contentType(): MediaType = overriddenType
+      }
+
+    assertThat(forwardingBody.contentType()).isEqualTo(overriddenType)
+    assertThat(delegate.contentType()).isEqualTo(originalType)
+    assertThat(forwardingBody.contentLength()).isEqualTo(5L)
+    assertThat(forwardingBody.isOneShot()).isEqualTo(oneShot)
+    assertThat(forwardingBody.isDuplex()).isEqualTo(duplex)
+
+    val sink = Buffer()
+    forwardingBody.writeTo(sink)
+    assertThat(sink.readUtf8()).isEqualTo("hello")
+  }
+
+  /**
+   * Verifies that the delegate's content type is forwarded, including null
+   * when the delegate does not specify one.
+   */
+  @ParameterizedTest
+  @NullSource
+  @ValueSource(strings = ["text/plain"])
+  fun forwardsContentType(contentType: String?) {
+    val mediaType = contentType?.toMediaType()
+    val delegate = byteArrayOf(1, 2, 3).toRequestBody(mediaType)
+    val forwardingBody = ForwardingRequestBody(delegate)
+
+    assertThat(forwardingBody.contentType()).isEqualTo(mediaType)
+  }
+}