On branch copilot-pr-20 Fix "2. **`SessionRequestBuilder.extractTrans…

…formCallbacks` returns `Object[]`** — MEDIUM-HIGH RISK" Your branch is up to date with 'upstream/copilot/sync-upstream-39-new-commits'. Changes not staged for commit: (use "git add <file>..." to update what will be committed) (use "git restore <file>..." to discard changes in working directory) modified: .gitignore modified: src/main/java/com/github/copilot/sdk/CopilotClient.java modified: src/main/java/com/github/copilot/sdk/SessionRequestBuilder.java modified: src/test/java/com/github/copilot/sdk/SessionRequestBuilderTest.java Untracked files: (use "git add <file>..." to include in what will be committed) src/main/java/com/github/copilot/sdk/ExtractedTransforms.java no changes added to commit (use "git add" and/or "git commit -a")
github · edburns · Mar 25, 2026 · Mar 24, 2026 · Mar 24, 2026 · Mar 24, 2026
commit 13242227b35088bd2c0f426673db483c44f314b5
diff --git a/.gitignore b/.gitignore
@@ -6,3 +6,4 @@ blog-copilotsdk/
 .claude/worktrees
 smoke-test
 *job-logs.txt
+temporary-prompts/
diff --git a/src/main/java/com/github/copilot/sdk/CopilotClient.java b/src/main/java/com/github/copilot/sdk/CopilotClient.java
@@ -336,17 +336,14 @@ public CompletableFuture<CopilotSession> createSession(SessionConfig config) {
             // Callbacks are registered with the session; a wire-safe copy of the
             // system message (with transform sections replaced by action="transform")
             // is used in the RPC request.
-            Object[] extracted = SessionRequestBuilder.extractTransformCallbacks(config.getSystemMessage());
-            var wireSystemMessage = (com.github.copilot.sdk.json.SystemMessageConfig) extracted[0];
-            @SuppressWarnings("unchecked")
-            var transformCallbacks = (java.util.Map<String, java.util.function.Function<String, java.util.concurrent.CompletableFuture<String>>>) extracted[1];
-            if (transformCallbacks != null) {
-                session.registerTransformCallbacks(transformCallbacks);
+            var extracted = SessionRequestBuilder.extractTransformCallbacks(config.getSystemMessage());
+            if (extracted.transformCallbacks() != null) {
+                session.registerTransformCallbacks(extracted.transformCallbacks());
             }
 
             var request = SessionRequestBuilder.buildCreateRequest(config, sessionId);
-            if (wireSystemMessage != config.getSystemMessage()) {
-                request.setSystemMessage(wireSystemMessage);
+            if (extracted.wireSystemMessage() != config.getSystemMessage()) {
+                request.setSystemMessage(extracted.wireSystemMessage());
             }
 
             return connection.rpc.invoke("session.create", request, CreateSessionResponse.class).thenApply(response -> {
@@ -406,17 +403,14 @@ public CompletableFuture<CopilotSession> resumeSession(String sessionId, ResumeS
             sessions.put(sessionId, session);
 
             // Extract transform callbacks from the system message config.
-            Object[] extracted = SessionRequestBuilder.extractTransformCallbacks(config.getSystemMessage());
-            var wireSystemMessage = (com.github.copilot.sdk.json.SystemMessageConfig) extracted[0];
-            @SuppressWarnings("unchecked")
-            var transformCallbacks = (java.util.Map<String, java.util.function.Function<String, java.util.concurrent.CompletableFuture<String>>>) extracted[1];
-            if (transformCallbacks != null) {
-                session.registerTransformCallbacks(transformCallbacks);
+            var extracted = SessionRequestBuilder.extractTransformCallbacks(config.getSystemMessage());
+            if (extracted.transformCallbacks() != null) {
+                session.registerTransformCallbacks(extracted.transformCallbacks());
             }
 
             var request = SessionRequestBuilder.buildResumeRequest(sessionId, config);
-            if (wireSystemMessage != config.getSystemMessage()) {
-                request.setSystemMessage(wireSystemMessage);
+            if (extracted.wireSystemMessage() != config.getSystemMessage()) {
+                request.setSystemMessage(extracted.wireSystemMessage());
             }
 
             return connection.rpc.invoke("session.resume", request, ResumeSessionResponse.class).thenApply(response -> {

diff --git a/src/main/java/com/github/copilot/sdk/ExtractedTransforms.java b/src/main/java/com/github/copilot/sdk/ExtractedTransforms.java
@@ -0,0 +1,30 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *--------------------------------------------------------------------------------------------*/
+
+package com.github.copilot.sdk;
+
+import java.util.Map;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Function;
+
+import com.github.copilot.sdk.json.SystemMessageConfig;
+
+/**
+ * Result of extracting transform callbacks from a {@link SystemMessageConfig}.
+ * <p>
+ * Holds a wire-safe copy of the system message config (with transform callbacks
+ * replaced by {@code action="transform"}) alongside the extracted callbacks
+ * that must be registered with the session.
+ *
+ * @param wireSystemMessage
+ *            the system message config safe for JSON serialization; may be
+ *            {@code null} when the input config was {@code null}
+ * @param transformCallbacks
+ *            transform callbacks keyed by section identifier; {@code null} when
+ *            no transforms were present
+ * @see SessionRequestBuilder#extractTransformCallbacks(SystemMessageConfig)
+ */
+record ExtractedTransforms(SystemMessageConfig wireSystemMessage,
+        Map<String, Function<String, CompletableFuture<String>>> transformCallbacks) {
+}
diff --git a/src/main/java/com/github/copilot/sdk/SessionRequestBuilder.java b/src/main/java/com/github/copilot/sdk/SessionRequestBuilder.java
@@ -47,13 +47,13 @@ private SessionRequestBuilder() {
      *
      * @param systemMessage
      *            the system message config, may be {@code null}
-     * @return a two-element array: {@code [wireConfig, callbacks]}; either may be
-     *         {@code null} if not applicable
+     * @return an {@link ExtractedTransforms} containing the wire-safe config and
+     *         any extracted callbacks
      */
-    static Object[] extractTransformCallbacks(SystemMessageConfig systemMessage) {
+    static ExtractedTransforms extractTransformCallbacks(SystemMessageConfig systemMessage) {
         if (systemMessage == null || systemMessage.getMode() != SystemMessageMode.CUSTOMIZE
                 || systemMessage.getSections() == null) {
-            return new Object[]{systemMessage, null};
+            return new ExtractedTransforms(systemMessage, null);
         }
 
         Map<String, Function<String, CompletableFuture<String>>> callbacks = new HashMap<>();
@@ -72,14 +72,14 @@ static Object[] extractTransformCallbacks(SystemMessageConfig systemMessage) {
         }
 
         if (callbacks.isEmpty()) {
-            return new Object[]{systemMessage, null};
+            return new ExtractedTransforms(systemMessage, null);
         }
 
         // Build a wire-safe copy of the system message with callbacks removed
         var wireConfig = new SystemMessageConfig().setMode(systemMessage.getMode())
                 .setContent(systemMessage.getContent()).setSections(wireSections);
 
-        return new Object[]{wireConfig, callbacks};
+        return new ExtractedTransforms(wireConfig, callbacks);
     }
 
     /**

diff --git a/src/test/java/com/github/copilot/sdk/SessionRequestBuilderTest.java b/src/test/java/com/github/copilot/sdk/SessionRequestBuilderTest.java
@@ -258,18 +258,18 @@ void testBuildResumeRequestWithAgent() {
 
     @Test
     void extractTransformCallbacks_nullSystemMessage_returnsNull() {
-        Object[] result = SessionRequestBuilder.extractTransformCallbacks(null);
-        assertNull(result[0]);
-        assertNull(result[1]);
+        ExtractedTransforms result = SessionRequestBuilder.extractTransformCallbacks(null);
+        assertNull(result.wireSystemMessage());
+        assertNull(result.transformCallbacks());
     }
 
     @Test
     void extractTransformCallbacks_appendMode_returnsOriginalConfig() {
         var config = new com.github.copilot.sdk.json.SystemMessageConfig()
                 .setMode(com.github.copilot.sdk.SystemMessageMode.APPEND).setContent("extra content");
-        Object[] result = SessionRequestBuilder.extractTransformCallbacks(config);
-        assertSame(config, result[0]);
-        assertNull(result[1]);
+        ExtractedTransforms result = SessionRequestBuilder.extractTransformCallbacks(config);
+        assertSame(config, result.wireSystemMessage());
+        assertNull(result.transformCallbacks());
     }
 
     @Test
@@ -278,32 +278,29 @@ void extractTransformCallbacks_customizeModeNoTransforms_returnsOriginalConfig()
                 .setAction(com.github.copilot.sdk.json.SectionOverrideAction.REMOVE));
         var config = new com.github.copilot.sdk.json.SystemMessageConfig()
                 .setMode(com.github.copilot.sdk.SystemMessageMode.CUSTOMIZE).setSections(sections);
-        Object[] result = SessionRequestBuilder.extractTransformCallbacks(config);
-        assertSame(config, result[0]);
-        assertNull(result[1]);
+        ExtractedTransforms result = SessionRequestBuilder.extractTransformCallbacks(config);
+        assertSame(config, result.wireSystemMessage());
+        assertNull(result.transformCallbacks());
     }
 
     @Test
-    @SuppressWarnings("unchecked")
     void extractTransformCallbacks_customizeModeWithTransform_extractsCallbacks() {
         var transformFn = (java.util.function.Function<String, CompletableFuture<String>>) content -> CompletableFuture
                 .completedFuture(content + " modified");
         var sections = Map.of("identity", new com.github.copilot.sdk.json.SectionOverride().setTransform(transformFn));
         var config = new com.github.copilot.sdk.json.SystemMessageConfig()
                 .setMode(com.github.copilot.sdk.SystemMessageMode.CUSTOMIZE).setSections(sections);
 
-        Object[] result = SessionRequestBuilder.extractTransformCallbacks(config);
+        ExtractedTransforms result = SessionRequestBuilder.extractTransformCallbacks(config);
 
         // Wire config should be different from original
-        assertNotSame(config, result[0]);
+        assertNotSame(config, result.wireSystemMessage());
         // Callbacks should be extracted
-        assertNotNull(result[1]);
-        var callbacks = (java.util.Map<String, java.util.function.Function<String, CompletableFuture<String>>>) result[1];
-        assertTrue(callbacks.containsKey("identity"));
+        assertNotNull(result.transformCallbacks());
+        assertTrue(result.transformCallbacks().containsKey("identity"));
         // Wire config should have transform action instead of callback
-        var wireConfig = (com.github.copilot.sdk.json.SystemMessageConfig) result[0];
-        assertNotNull(wireConfig.getSections());
-        var wireSection = wireConfig.getSections().get("identity");
+        assertNotNull(result.wireSystemMessage().getSections());
+        var wireSection = result.wireSystemMessage().getSections().get("identity");
         assertNotNull(wireSection);
         assertEquals(com.github.copilot.sdk.json.SectionOverrideAction.TRANSFORM, wireSection.getAction());
         assertNull(wireSection.getTransform());