Filter empty text parts when streaming

.changeset/seven-oranges-care.md

@@ -0,0 +1,5 @@
+---
+'@firebase/vertexai': patch
+---
+
+Filter out empty text parts from streaming responses.

packages/vertexai/src/requests/stream-reader.test.ts

@@ -220,6 +220,24 @@ describe('processStream', () => {
     }
     expect(foundCitationMetadata).to.be.true;
   });
+  it('removes empty text parts', async () => {
+    const fakeResponse = getMockResponseStreaming(
+      'streaming-success-empty-text-part.txt'
+    );
+    const result = processStream(fakeResponse as Response);
+    const aggregatedResponse = await result.response;
+    console.log(aggregatedResponse.candidates?.[0].content.parts);
+    expect(aggregatedResponse.text()).to.equal('1');
+    expect(aggregatedResponse.candidates?.length).to.equal(1);
+    expect(aggregatedResponse.candidates?.[0].content.parts.length).to.equal(1);
+
+    // The chunk with the empty text part will still go through the stream
+    let numChunks = 0;
+    for await (const _ of result.stream) {
+      numChunks++;
+    }
+    expect(numChunks).to.equal(2);
+  });
 });
 
 describe('aggregateResponses', () => {

packages/vertexai/src/requests/stream-reader.ts

@@ -62,6 +62,7 @@ async function getResponsePromise(
       );
       return enhancedResponse;
     }
+
     allResponses.push(value);
   }
 }
@@ -184,7 +185,13 @@ export function aggregateResponses(
           }
           const newPart: Partial<Part> = {};
           for (const part of candidate.content.parts) {
-            if (part.text) {
+            if (part.text !== undefined) {
+              // The backend can send empty text parts. If these are sent back
+              // (e.g. in chat history), the backend will respond with an error.
+              // To prevent this, ignore empty text parts.
+              if (part.text === '') {
+                continue;
+              }
               newPart.text = part.text;
             }
             if (part.functionCall) {

scripts/update_vertexai_responses.sh

@@ -17,7 +17,7 @@
 # This script replaces mock response files for Vertex AI unit tests with a fresh
 # clone of the shared repository of Vertex AI test data.
 
-RESPONSES_VERSION='v5.*' # The major version of mock responses to use
+RESPONSES_VERSION='v6.*' # The major version of mock responses to use
 REPO_NAME="vertexai-sdk-test-data"
 REPO_LINK="https://github.com/FirebaseExtended/$REPO_NAME.git"