Merge pull request #4216 from NilsR0711/fix/4197-agent-end-destroys-streaming-message

fix(pi-coding-agent): finalize streaming component on agent_end instead of removing it

packages/pi-coding-agent/src/core/chat-controller-ordering.test.ts

@@ -813,3 +813,83 @@ test("chat-controller updates pinned zone after sub-turn shrink", async () => {
 	// Finalize so the module-level pinned spinner (setInterval) is torn down and the test process can exit.
 	await handleAgentEvent(host, { type: "message_end", message: makeAssistant([{ type: "text", text: "second" }, t2]) } as any);
 });
+
+test("chat-controller: agent_end without message_end must not remove streaming component from DOM (regression #4197)", async () => {
+	const host = createHost();
+
+	await handleAgentEvent(host, {
+		type: "message_start",
+		message: makeAssistant([]),
+	} as any);
+
+	// Simulate partial streaming that creates an AssistantMessageComponent
+	await handleAgentEvent(host, {
+		type: "message_update",
+		message: makeAssistant([{ type: "text", text: "partial answer" }]),
+		assistantMessageEvent: {
+			type: "text_delta",
+			contentIndex: 0,
+			delta: "partial answer",
+			partial: makeAssistant([{ type: "text", text: "partial answer" }]),
+		},
+	} as any);
+
+	// Precondition: component is in DOM
+	assert.equal(
+		host.chatContainer.children.length,
+		1,
+		"streaming component must be in DOM after message_update",
+	);
+	const comp = host.chatContainer.children[0];
+
+	// Simulate abort: agent_end fires WITHOUT message_end
+	await handleAgentEvent(host, { type: "agent_end" } as any);
+
+	assert.equal(
+		host.chatContainer.children.length,
+		1,
+		"agent_end must NOT remove the streaming component from the DOM (issue #4197)",
+	);
+	assert.equal(
+		host.chatContainer.children[0],
+		comp,
+		"the same component instance must remain in the DOM after agent_end",
+	);
+});
+
+test("chat-controller: agent_end after message_end must not alter DOM", async () => {
+	const host = createHost();
+	const content = [{ type: "text", text: "complete answer" }];
+
+	await handleAgentEvent(host, {
+		type: "message_start",
+		message: makeAssistant([]),
+	} as any);
+
+	await handleAgentEvent(host, {
+		type: "message_update",
+		message: makeAssistant(content),
+		assistantMessageEvent: {
+			type: "text_delta",
+			contentIndex: 0,
+			delta: "complete answer",
+			partial: makeAssistant(content),
+		},
+	} as any);
+
+	await handleAgentEvent(host, {
+		type: "message_end",
+		message: makeAssistant(content),
+	} as any);
+
+	const countAfterMessageEnd = host.chatContainer.children.length;
+	assert.ok(countAfterMessageEnd > 0, "component must be present after message_end");
+
+	await handleAgentEvent(host, { type: "agent_end" } as any);
+
+	assert.equal(
+		host.chatContainer.children.length,
+		countAfterMessageEnd,
+		"agent_end after message_end must not add or remove DOM nodes",
+	);
+});

packages/pi-coding-agent/src/modes/interactive/controllers/chat-controller.ts

@@ -546,11 +546,14 @@ export async function handleAgentEvent(host: InteractiveModeStateHost & {
 				host.loadingAnimation = undefined;
 				host.statusContainer.clear();
 			}
-			if (host.streamingComponent) {
-				host.chatContainer.removeChild(host.streamingComponent);
-				host.streamingComponent = undefined;
-				host.streamingMessage = undefined;
+			if (host.streamingComponent && host.streamingMessage) {
+				host.streamingComponent.setShowMetadata(true);
+				host.streamingComponent.updateContent(host.streamingMessage);
 			}
+			host.streamingComponent = undefined;
+			host.streamingMessage = undefined;
+			renderedSegments = [];
+			lastContentLength = 0;
 			host.pendingTools.clear();
 			// Pinned output is only useful while work is actively streaming.
 			// Keep chat history as the single source after completion.