Flaky CI fix (#1647)

Flushing before sending `TaskCompleteEvent` and ending the submission
loop to avoid race conditions.

codex-rs/exec/src/lib.rs

@@ -5,7 +5,6 @@ mod event_processor_with_json_output;
 
 use std::io::IsTerminal;
 use std::io::Read;
-use std::path::Path;
 use std::path::PathBuf;
 use std::sync::Arc;
 
@@ -28,6 +27,7 @@ use tracing::error;
 use tracing::info;
 use tracing_subscriber::EnvFilter;
 
+use crate::event_processor::CodexStatus;
 use crate::event_processor::EventProcessor;
 
 pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> anyhow::Result<()> {
@@ -123,11 +123,12 @@ pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> any
 
     let config = Config::load_with_cli_overrides(cli_kv_overrides, overrides)?;
     let mut event_processor: Box<dyn EventProcessor> = if json_mode {
-        Box::new(EventProcessorWithJsonOutput::new())
+        Box::new(EventProcessorWithJsonOutput::new(last_message_file.clone()))
     } else {
         Box::new(EventProcessorWithHumanOutput::create_with_ansi(
             stdout_with_ansi,
             &config,
+            last_message_file.clone(),
         ))
     };
 
@@ -224,40 +225,17 @@ pub async fn run_main(cli: Cli, codex_linux_sandbox_exe: Option<PathBuf>) -> any
 
     // Run the loop until the task is complete.
     while let Some(event) = rx.recv().await {
-        let (is_last_event, last_assistant_message) = match &event.msg {
-            EventMsg::TaskComplete(TaskCompleteEvent { last_agent_message }) => {
-                (true, last_agent_message.clone())
+        let shutdown: CodexStatus = event_processor.process_event(event);
+        match shutdown {
+            CodexStatus::Running => continue,
+            CodexStatus::InitiateShutdown => {
+                codex.submit(Op::Shutdown).await?;
+            }
+            CodexStatus::Shutdown => {
+                break;
             }
-            _ => (false, None),
-        };
-        event_processor.process_event(event);
-        if is_last_event {
-            handle_last_message(last_assistant_message, last_message_file.as_deref())?;
-            break;
         }
     }
 
     Ok(())
 }
-
-fn handle_last_message(
-    last_agent_message: Option<String>,
-    last_message_file: Option<&Path>,
-) -> std::io::Result<()> {
-    match (last_agent_message, last_message_file) {
-        (Some(last_agent_message), Some(last_message_file)) => {
-            // Last message and a file to write to.
-            std::fs::write(last_message_file, last_agent_message)?;
-        }
-        (None, Some(last_message_file)) => {
-            eprintln!(
-                "Warning: No last message to write to file: {}",
-                last_message_file.to_string_lossy()
-            );
-        }
-        (_, None) => {
-            // No last message and no file to write to.
-        }
-    }
-    Ok(())
-}