bug #466 [Platform][VertexAI] Update ResultConverter (pentiminax)

This PR was squashed before being merged into the main branch.

Discussion
----------

[Platform][VertexAI] Update `ResultConverter`

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| Docs?         | no
| License       | MIT

Same as #421 but for VertexAI bridge

This PR fixes a crash in the Gemini ResultConverter when handling responses that only contained executableCode and codeExecutionResult parts.

Rather than duplicating the code, I created a trait that is used in both bridges.
I also reused the same test fixtures.

Commits
-------

a46ddcf [Platform][VertexAI] Update `ResultConverter`

Author: OskarStark

fixtures/Bridge/VertexAi/code_execution_outcome_deadline_exceeded.json

@@ -0,0 +1,31 @@
+{
+    "candidates": [
+        {
+            "content": {
+                "parts": [
+                    {
+                        "text": "First text"
+                    },
+                    {
+                        "executableCode": {
+                            "language": "PYTHON",
+                            "code": "print('Hello, World!')"
+                        }
+                    },
+                    {
+                        "codeExecutionResult": {
+                            "outcome": "OUTCOME_DEADLINE_EXCEEDED",
+                            "output": "An error occurred during code execution."
+                        }
+                    },
+                    {
+                        "text": "Last text"
+                    }
+                ],
+                "role": "model"
+            },
+            "finishReason": "STOP",
+            "index": 0
+        }
+    ]
+}

fixtures/Bridge/VertexAi/code_execution_outcome_failed.json

@@ -0,0 +1,31 @@
+{
+    "candidates": [
+        {
+            "content": {
+                "parts": [
+                    {
+                        "text": "First text"
+                    },
+                    {
+                        "executableCode": {
+                            "language": "PYTHON",
+                            "code": "print('Hello, World!')"
+                        }
+                    },
+                    {
+                        "codeExecutionResult": {
+                            "outcome": "OUTCOME_FAILED",
+                            "output": "An error occurred during code execution."
+                        }
+                    },
+                    {
+                        "text": "Last text"
+                    }
+                ],
+                "role": "model"
+            },
+            "finishReason": "STOP",
+            "index": 0
+        }
+    ]
+}

fixtures/Bridge/VertexAi/code_execution_outcome_ok.json

@@ -0,0 +1,37 @@
+{
+    "candidates": [
+        {
+            "content": {
+                "parts": [
+                    {
+                        "text": "First text"
+                    },
+                    {
+                        "executableCode": {
+                            "language": "PYTHON",
+                            "code": "print('Hello, World!')"
+                        }
+                    },
+                    {
+                        "codeExecutionResult": {
+                            "outcome": "OUTCOME_OK",
+                            "output": "Hello, World!"
+                        }
+                    },
+                    {
+                        "text": "Second text\n"
+                    },
+                    {
+                        "text": "Third text\n"
+                    },
+                    {
+                        "text": "Fourth text"
+                    }
+                ],
+                "role": "model"
+            },
+            "finishReason": "STOP",
+            "index": 0
+        }
+    ]
+}

src/platform/src/Bridge/VertexAi/Gemini/ResultConverter.php

@@ -31,6 +31,10 @@
  */
 final readonly class ResultConverter implements ResultConverterInterface
 {
+    public const OUTCOME_OK = 'OUTCOME_OK';
+    public const OUTCOME_FAILED = 'OUTCOME_FAILED';
+    public const OUTCOME_DEADLINE_EXCEEDED = 'OUTCOME_DEADLINE_EXCEEDED';
+
     public function supports(BaseModel $model): bool
     {
         return $model instanceof Model;
@@ -119,21 +123,44 @@ private function convertStream(HttpResponse $result): \Generator
      *             text?: string
      *         }[]
      *     }
-     * } $choices
+     * } $choice
      */
-    private function convertChoice(array $choices): ToolCallResult|TextResult
+    private function convertChoice(array $choice): ToolCallResult|TextResult
     {
-        $content = $choices['content']['parts'][0] ?? [];
+        $contentParts = $choice['content']['parts'];
+
+        if (1 === \count($contentParts)) {
+            $contentPart = $contentParts[0];
+
+            if (isset($contentPart['functionCall'])) {
+                return new ToolCallResult($this->convertToolCall($contentPart['functionCall']));
+            }
+
+            if (isset($contentPart['text'])) {
+                return new TextResult($contentPart['text']);
+            }
+
+            throw new RuntimeException(\sprintf('Unsupported finish reason "%s".', $choice['finishReason']));
+        }
+
+        $content = '';
+        $successfulCodeExecutionDetected = false;
+        foreach ($contentParts as $contentPart) {
+            if ($this->isSuccessfulCodeExecution($contentPart)) {
+                $successfulCodeExecutionDetected = true;
+                continue;
+            }
 
-        if (isset($content['functionCall'])) {
-            return new ToolCallResult($this->convertToolCall($content['functionCall']));
+            if ($successfulCodeExecutionDetected) {
+                $content .= $contentPart['text'];
+            }
         }
 
-        if (isset($content['text'])) {
-            return new TextResult($content['text']);
+        if ('' !== $content) {
+            return new TextResult($content);
         }
 
-        throw new RuntimeException(\sprintf('Unsupported finish reason "%s".', $choices['finishReason']));
+        throw new RuntimeException('Code execution failed.');
     }
 
     /**
@@ -146,4 +173,23 @@ private function convertToolCall(array $toolCall): ToolCall
     {
         return new ToolCall($toolCall['name'], $toolCall['name'], $toolCall['args']);
     }
+
+    /**
+     * @param array{
+     *     codeExecutionResult?: array{
+     *         outcome: self::OUTCOME_*,
+     *         output: string
+     *     }
+     * } $contentPart
+     */
+    private function isSuccessfulCodeExecution(array $contentPart): bool
+    {
+        if (!isset($contentPart['codeExecutionResult'])) {
+            return false;
+        }
+
+        $result = $contentPart['codeExecutionResult'];
+
+        return self::OUTCOME_OK === $result['outcome'];
+    }
 }

src/platform/tests/Bridge/VertexAi/Gemini/ResultConverterTest.php

@@ -46,8 +46,54 @@ public function testItConvertsAResponseToAVectorResult()
         $result = $resultConverter->convert(new RawHttpResult($response));
 
         // Assert
-
         $this->assertInstanceOf(TextResult::class, $result);
         $this->assertSame('Hello, world!', $result->getContent());
     }
+
+    public function testItReturnsAggregatedTextOnSuccess()
+    {
+        $response = $this->createStub(ResponseInterface::class);
+        $responseContent = file_get_contents(\dirname(__DIR__, 6).'/fixtures/Bridge/VertexAi/code_execution_outcome_ok.json');
+
+        $response
+            ->method('toArray')
+            ->willReturn(json_decode($responseContent, true));
+
+        $converter = new ResultConverter();
+
+        $result = $converter->convert(new RawHttpResult($response));
+        $this->assertInstanceOf(TextResult::class, $result);
+
+        $this->assertEquals("Second text\nThird text\nFourth text", $result->getContent());
+    }
+
+    public function testItThrowsExceptionOnFailure()
+    {
+        $response = $this->createStub(ResponseInterface::class);
+        $responseContent = file_get_contents(\dirname(__DIR__, 6).'/fixtures/Bridge/VertexAi/code_execution_outcome_failed.json');
+
+        $response
+            ->method('toArray')
+            ->willReturn(json_decode($responseContent, true));
+
+        $converter = new ResultConverter();
+
+        $this->expectException(\RuntimeException::class);
+        $converter->convert(new RawHttpResult($response));
+    }
+
+    public function testItThrowsExceptionOnTimeout()
+    {
+        $response = $this->createStub(ResponseInterface::class);
+        $responseContent = file_get_contents(\dirname(__DIR__, 6).'/fixtures/Bridge/VertexAi/code_execution_outcome_deadline_exceeded.json');
+
+        $response
+            ->method('toArray')
+            ->willReturn(json_decode($responseContent, true));
+
+        $converter = new ResultConverter();
+
+        $this->expectException(\RuntimeException::class);
+        $converter->convert(new RawHttpResult($response));
+    }
 }