Fix OpenAI empty choices panic (#5248)

Signed-off-by: Arya Pratap Singh <notaryasingh@gmail.com>

crates/goose/src/providers/formats/openai.rs

@@ -7,6 +7,7 @@ use crate::providers::utils::{
 };
 use anyhow::{anyhow, Error};
 use async_stream::try_stream;
+use chrono;
 use futures::Stream;
 use rmcp::model::{
     object, AnnotateAble, CallToolRequestParam, Content, ErrorCode, ErrorData, RawContent,
@@ -281,7 +282,18 @@ pub fn format_tools(tools: &[Tool]) -> anyhow::Result<Vec<Value>> {
 
 /// Convert OpenAI's API response to internal Message format
 pub fn response_to_message(response: &Value) -> anyhow::Result<Message> {
-    let original = &response["choices"][0]["message"];
+    let Some(original) = response
+        .get("choices")
+        .and_then(|c| c.get(0))
+        .and_then(|m| m.get("message"))
+    else {
+        return Ok(Message::new(
+            Role::Assistant,
+            chrono::Utc::now().timestamp(),
+            Vec::new(),
+        ));
+    };
+
     let mut content = Vec::new();
 
     if let Some(text) = original.get("content") {
@@ -465,12 +477,14 @@ where
 
             if chunk.choices.is_empty() {
                 yield (None, usage)
-            } else if let Some(tool_calls) = &chunk.choices[0].delta.tool_calls {
+            } else if chunk.choices[0].delta.tool_calls.as_ref().is_some_and(|tc| !tc.is_empty()) {
                 let mut tool_call_data: std::collections::HashMap<i32, (String, String, String)> = std::collections::HashMap::new();
 
-                for tool_call in tool_calls {
+                if let Some(tool_calls) = &chunk.choices[0].delta.tool_calls {
-                    if let (Some(index), Some(id), Some(name)) = (tool_call.index, &tool_call.id, &tool_call.function.name) {
+                    for tool_call in tool_calls {
-                        tool_call_data.insert(index, (id.clone(), name.clone(), tool_call.function.arguments.clone()));
+                        if let (Some(index), Some(id), Some(name)) = (tool_call.index, &tool_call.id, &tool_call.function.name) {
+                            tool_call_data.insert(index, (id.clone(), name.clone(), tool_call.function.arguments.clone()));
+                        }
                     }
                 }
 
@@ -489,23 +503,27 @@ where
                                 let tool_chunk: StreamingChunk = serde_json::from_str(line)
                                     .map_err(|e| anyhow!("Failed to parse streaming chunk: {}: {:?}", e, &line))?;
 
-                                if let Some(delta_tool_calls) = &tool_chunk.choices[0].delta.tool_calls {
+                                if !tool_chunk.choices.is_empty() {
-                                    for delta_call in delta_tool_calls {
+                                    if let Some(delta_tool_calls) = &tool_chunk.choices[0].delta.tool_calls {
-                                        if let Some(index) = delta_call.index {
+                                        for delta_call in delta_tool_calls {
-                                            if let Some((_, _, ref mut args)) = tool_call_data.get_mut(&index) {
+                                            if let Some(index) = delta_call.index {
-                                                args.push_str(&delta_call.function.arguments);
+                                                if let Some((_, _, ref mut args)) = tool_call_data.get_mut(&index) {
-                                            } else if let (Some(id), Some(name)) = (&delta_call.id, &delta_call.function.name) {
+                                                    args.push_str(&delta_call.function.arguments);
-                                                tool_call_data.insert(index, (id.clone(), name.clone(), delta_call.function.arguments.clone()));
+                                                } else if let (Some(id), Some(name)) = (&delta_call.id, &delta_call.function.name) {
+                                                    tool_call_data.insert(index, (id.clone(), name.clone(), delta_call.function.arguments.clone()));
+                                                }
                                             }
                                         }
+                                    } else {
+                                        done = true;
+                                    }
+
+                                    if tool_chunk.choices[0].finish_reason == Some("tool_calls".to_string()) {
+                                        done = true;
                                     }
                                 } else {
                                     done = true;
                                 }
-
-                                if tool_chunk.choices[0].finish_reason == Some("tool_calls".to_string()) {
-                                    done = true;
-                                }
                             }
                         } else {
                             break;
@@ -563,7 +581,8 @@ where
                     Some(msg),
                     usage,
                 )
-            } else if let Some(text) = &chunk.choices[0].delta.content {
+            } else if chunk.choices[0].delta.content.is_some() {
+                let text = chunk.choices[0].delta.content.as_ref().unwrap();
                 let mut msg = Message::new(
                     Role::Assistant,
                     chrono::Utc::now().timestamp(),