fix(storage): handle append_file missing-path errors as not_found

openviking/storage/viking_fs.py

@@ -1728,8 +1728,12 @@ async def append_file(
             except AGFSHTTPError as e:
                 if e.status_code != 404:
                     raise
-            except AGFSClientError:
-                raise
+            except AGFSClientError as e:
+                if "not found" not in (str(e) or "").lower():
+                    raise
+            except RuntimeError as e:
+                if "not found" not in (str(e) or "").lower():
+                    raise
 
             await self._ensure_parent_dirs(path)
             final_content = (existing + content).encode("utf-8")

tests/misc/test_append_file_missing.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+# Copyright (c) 2026 Beijing Volcano Engine Technology Co., Ltd.
+# SPDX-License-Identifier: AGPL-3.0
+"""Ensures VikingFS.append_file treats missing files as empty content Before writing."""
+
+import contextvars
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+from openviking.pyagfs.exceptions import AGFSClientError
+
+
+def _make_viking_fs():
+    """Create a VikingFS instance with all required hooks mocked."""
+    from openviking.storage.viking_fs import VikingFS
+
+    fs = VikingFS.__new__(VikingFS)
+    fs.agfs = MagicMock()
+    fs.query_embedder = None
+    fs.vector_store = None
+    fs._bound_ctx = contextvars.ContextVar("vikingfs_bound_ctx", default=None)
+    return fs
+
+
+@pytest.mark.asyncio
+async def test_append_file_missing_runtime_error():
+    """Missing file should not crash when append_file reads a RuntimeError 'not found'."""
+    fs = _make_viking_fs()
+    fs._ensure_parent_dirs = AsyncMock()
+    fs.agfs.read.side_effect = RuntimeError("not found: /default/session/.../messages.jsonl")
+    fs.agfs.write = MagicMock()
+
+    await fs.append_file("viking://session/default/foo/messages.jsonl", "hello\n")
+
+    fs.agfs.write.assert_called_once()
+    path, payload = fs.agfs.write.call_args[0]
+    assert "messages.jsonl" in path
+    assert payload == b"hello\n"
+
+
+@pytest.mark.asyncio
+async def test_append_file_missing_client_error():
+    """AGFSClientError carrying 'not found' should also be treated as empty existing content."""
+    fs = _make_viking_fs()
+    fs._ensure_parent_dirs = AsyncMock()
+    fs.agfs.read.side_effect = AGFSClientError("not found: /default/session/default/messages.jsonl")
+    fs.agfs.write = MagicMock()
+
+    await fs.append_file("viking://session/default/bar/messages.jsonl", "line\n")
+
+    fs.agfs.write.assert_called_once()
+    _, payload = fs.agfs.write.call_args[0]
+    assert payload.endswith(b"line\n")
+
+
+@pytest.mark.asyncio
+async def test_append_file_other_runtime_error_bubbles():
+    """RuntimeErrors without 'not found' should still propagate."""
+    fs = _make_viking_fs()
+    fs._ensure_parent_dirs = AsyncMock()
+    fs.agfs.read.side_effect = RuntimeError("permission denied")
+
+    with pytest.raises(RuntimeError):
+        await fs.append_file("viking://session/default/bad/messages.jsonl", "x\n")