fix(interpreter): report file synchronization failures

dspy/primitives/python_interpreter.py

@@ -266,9 +266,11 @@ def _sync_files(self):
         for path in self.enable_write_paths:
             virtual_path = f"/sandbox/{os.path.basename(str(path))}"
             host_path = _canonicalize_path(path)
-            sync_msg = _jsonrpc_notification("sync_file", {"virtual_path": virtual_path, "host_path": host_path})
-            self.deno_process.stdin.write(sync_msg + "\n")
-            self.deno_process.stdin.flush()
+            self._send_request(
+                "sync_file",
+                {"virtual_path": virtual_path, "host_path": host_path},
+                f"syncing {path}",
+            )
 
     def _extract_parameters(self, fn: Callable) -> list[dict]:
         """Extract parameter info from a callable for sandbox registration."""

dspy/primitives/runner.js

@@ -244,17 +244,20 @@ while (true) {
   const requestId = input.id; // May be undefined for notifications
 
   // Handle notifications (no response expected)
+  if (method === "shutdown") break;
+
   if (method === "sync_file") {
+    const virtualPath = params.virtual_path;
+    const hostPath = params.host_path || virtualPath;
     try {
-      const virtualPath = params.virtual_path;
-      const hostPath = params.host_path || virtualPath;
       await Deno.writeFile(hostPath, pyodide.FS.readFile(virtualPath));
-    } catch (e) { /* ignore sync errors */ }
+      console.log(jsonrpcResult({ synced: virtualPath }, requestId));
+    } catch (e) {
+      console.log(jsonrpcError(JSONRPC_APP_ERRORS.RuntimeError, `Failed to sync file: ${e.message}`, requestId));
+    }
     continue;
   }
 
-  if (method === "shutdown") break;
-
   // Handle requests (expect response)
   if (method === "mount_file") {
     const hostPath = params.host_path;

tests/primitives/test_python_interpreter.py

@@ -181,6 +181,18 @@ def test_enable_write_flag(tmp_path):
         assert f.read() == "original_content", "File should not be changed when sync_files is False"
 
 
+def test_sync_failure_is_reported(tmp_path):
+    testfile_path = tmp_path / "sync_failure.txt"
+    testfile_path.write_text("original_content")
+    virtual_path = f"/sandbox/{testfile_path.name}"
+
+    with PythonInterpreter(enable_write_paths=[testfile_path]) as interpreter:
+        with pytest.raises(CodeInterpreterError, match="Failed to sync file"):
+            interpreter.execute(f"import os\nos.remove({virtual_path!r})")
+
+    assert testfile_path.read_text() == "original_content"
+
+
 def test_enable_net_flag():
     test_url = "https://example.com"