Fix Google AI system prompt JSON (#1374)

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> [!IMPORTANT]
> Fix JSON structure in Google AI client, add GeminiOpenAiGeneric
client, and introduce new test functions for Gemini in multiple files.
> 
>   - **Behavior**:
> - Fix JSON structure in `googleai_client.rs` by renaming
`system_instructions` to `system_instruction` and wrapping `parts` in a
JSON object.
>     - Rename `messages` to `contents` in `googleai_client.rs`.
>   - **Clients**:
> - Add `GeminiOpenAiGeneric` client in `clients.baml` with
`openai-generic` provider.
>   - **Functions**:
> - Add `TestGeminiSystemAsChat` and `TestGeminiOpenAiGeneric` functions
in `test-files/providers/gemini.baml`.
> - Add corresponding async and sync functions in `async_client.py`,
`sync_client.py`, and `client.rb`.
>   - **Tests**:
> - Add tests for `TestGeminiSystemAsChat` and `TestGeminiOpenAiGeneric`
in `test_functions.py`.
> 
> <sup>This description was created by </sup>[<img alt="Ellipsis"
src="https://img.shields.io/badge/Ellipsis-blue?color=175173">](https://www.ellipsis.dev?ref=BoundaryML%2Fbaml&utm_source=github&utm_medium=referral)<sup>
for b2e08a4. It will automatically
update as commits are pushed.</sup>

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engine/baml-runtime/src/internal/llm_client/primitive/google/googleai_client.rs

@@ -403,11 +403,13 @@ impl ToProviderMessageExt for GoogleAIClient {
         if let Some(content) = first.first() {
             if content.role == "system" {
                 res.insert(
-                    "system_instructions".into(),
-                    json!(self.parts_to_message(&content.parts)?),
+                    "system_instruction".into(),
+                    json!({
+                        "parts": self.parts_to_message(&content.parts)?
+                    }),
                 );
                 res.insert(
-                    "messages".into(),
+                    "contents".into(),
                     others
                         .iter()
                         .map(|c| self.role_to_message(c))

integ-tests/baml_src/clients.baml

@@ -95,6 +95,15 @@ client<llm> Gemini {
   }
 }
 
+client<llm> GeminiOpenAiGeneric {
+  provider "openai-generic"
+  options {
+    base_url "https://generativelanguage.googleapis.com/v1beta/"
+    model "gemini-1.5-flash"
+    api_key env.GOOGLE_API_KEY
+  }
+}
+
 client<llm> Vertex {
   provider vertex-ai
   options {

integ-tests/baml_src/test-files/providers/gemini.baml

@@ -14,6 +14,22 @@ function TestGeminiSystem(input: string) -> string {
   "#
 }
 
+function TestGeminiSystemAsChat(input: string) -> string {
+  client Gemini
+  prompt #"
+    {{ _.role('system') }} You are a helpful assistant
+
+    {{_.role("user")}} Write a nice short story about {{ input }}
+  "#
+}
+
+function TestGeminiOpenAiGeneric() -> string {
+  client GeminiOpenAiGeneric
+  prompt #"{{_.role("system")}} You are a helpful assistant
+  {{_.role("user")}} Write a poem about llamas
+  "#
+}
+
 test TestName {
   functions [TestGeminiSystem]
   args {

integ-tests/python/baml_client/async_client.py

@@ -2810,6 +2810,29 @@ async def TestGemini(
       )
       return cast(str, raw.cast_to(types, types))
 
+    async def TestGeminiOpenAiGeneric(
+        self,
+
+        baml_options: BamlCallOptions = {},
+    ) -> str:
+      __tb__ = baml_options.get("tb", None)
+      if __tb__ is not None:
+        tb = __tb__._tb # type: ignore (we know how to use this private attribute)
+      else:
+        tb = None
+      __cr__ = baml_options.get("client_registry", None)
+
+      raw = await self.__runtime.call_function(
+        "TestGeminiOpenAiGeneric",
+        {
+
+        },
+        self.__ctx_manager.get(),
+        tb,
+        __cr__,
+      )
+      return cast(str, raw.cast_to(types, types))
+
     async def TestGeminiSystem(
         self,
         input: str,
@@ -2833,6 +2856,29 @@ async def TestGeminiSystem(
       )
       return cast(str, raw.cast_to(types, types))
 
+    async def TestGeminiSystemAsChat(
+        self,
+        input: str,
+        baml_options: BamlCallOptions = {},
+    ) -> str:
+      __tb__ = baml_options.get("tb", None)
+      if __tb__ is not None:
+        tb = __tb__._tb # type: ignore (we know how to use this private attribute)
+      else:
+        tb = None
+      __cr__ = baml_options.get("client_registry", None)
+
+      raw = await self.__runtime.call_function(
+        "TestGeminiSystemAsChat",
+        {
+          "input": input,
+        },
+        self.__ctx_manager.get(),
+        tb,
+        __cr__,
+      )
+      return cast(str, raw.cast_to(types, types))
+
     async def TestImageInput(
         self,
         img: baml_py.Image,
@@ -6888,6 +6934,35 @@ def TestGemini(
         self.__ctx_manager.get(),
       )
 
+    def TestGeminiOpenAiGeneric(
+        self,
+
+        baml_options: BamlCallOptions = {},
+    ) -> baml_py.BamlStream[Optional[str], str]:
+      __tb__ = baml_options.get("tb", None)
+      if __tb__ is not None:
+        tb = __tb__._tb # type: ignore (we know how to use this private attribute)
+      else:
+        tb = None
+      __cr__ = baml_options.get("client_registry", None)
+
+      raw = self.__runtime.stream_function(
+        "TestGeminiOpenAiGeneric",
+        {
+        },
+        None,
+        self.__ctx_manager.get(),
+        tb,
+        __cr__,
+      )
+
+      return baml_py.BamlStream[Optional[str], str](
+        raw,
+        lambda x: cast(Optional[str], x.cast_to(types, partial_types)),
+        lambda x: cast(str, x.cast_to(types, types)),
+        self.__ctx_manager.get(),
+      )
+
     def TestGeminiSystem(
         self,
         input: str,
@@ -6918,6 +6993,36 @@ def TestGeminiSystem(
         self.__ctx_manager.get(),
       )
 
+    def TestGeminiSystemAsChat(
+        self,
+        input: str,
+        baml_options: BamlCallOptions = {},
+    ) -> baml_py.BamlStream[Optional[str], str]:
+      __tb__ = baml_options.get("tb", None)
+      if __tb__ is not None:
+        tb = __tb__._tb # type: ignore (we know how to use this private attribute)
+      else:
+        tb = None
+      __cr__ = baml_options.get("client_registry", None)
+
+      raw = self.__runtime.stream_function(
+        "TestGeminiSystemAsChat",
+        {
+          "input": input,
+        },
+        None,
+        self.__ctx_manager.get(),
+        tb,
+        __cr__,
+      )
+
+      return baml_py.BamlStream[Optional[str], str](
+        raw,
+        lambda x: cast(Optional[str], x.cast_to(types, partial_types)),
+        lambda x: cast(str, x.cast_to(types, types)),
+        self.__ctx_manager.get(),
+      )
+
     def TestImageInput(
         self,
         img: baml_py.Image,