fix: buffer data in meta plugin for finalize command

Co-authored-by: aider (openai/andrew.openrouter.qwen.qwen3-coder) <aider@aider.chat>

src/meta_plugin/program.rs

@@ -17,6 +17,7 @@ pub struct MetaPluginProgram {
     pub supported: bool,
     pub meta_name: String,
     pub is_default: bool,
+    buffer: Vec<u8>,
 }
 
 impl MetaPluginProgram {
@@ -30,6 +31,7 @@ impl MetaPluginProgram {
             supported,
             meta_name,
             is_default,
+            buffer: Vec::new(),
         }
     }
 }
@@ -69,12 +71,20 @@ impl MetaPlugin for MetaPluginProgram {
 
         debug!("META: Executing command for finalize: {:?} {:?}", program, args);
 
-        let output = Command::new(program)
+        let mut process = Command::new(program)
             .args(args)
-            .stdin(Stdio::null())
+            .stdin(Stdio::piped())
             .stdout(Stdio::piped())
             .stderr(Stdio::piped())
-            .output()?;
+            .spawn()
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, format!("Failed to spawn process: {}", e)))?;
+
+        let stdin = process.stdin.as_mut().unwrap();
+        stdin.write_all(&self.buffer)
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, format!("Failed to write to stdin: {}", e)))?;
+
+        let output = process.wait_with_output()
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, format!("Failed to wait for process: {}", e)))?;
 
         if output.status.success() {
             let stdout = String::from_utf8_lossy(&output.stdout);
@@ -88,8 +98,8 @@ impl MetaPlugin for MetaPluginProgram {
         }
     }
 
-    fn update(&mut self, _data: &[u8]) {
-        // This is handled by the ProgramWriter implementation
+    fn update(&mut self, data: &[u8]) {
+        self.buffer.extend_from_slice(data);
     }
 
     fn meta_name(&mut self) -> String {