Limit the shadow FS initialization to three attempts,

emit a useful warning and add a test for permission error

Author: krassowski

python_packages/jupyter_lsp/jupyter_lsp/tests/test_virtual_documents_shadow.py

@@ -1,9 +1,13 @@
+import logging
+import stat
 from pathlib import Path
 from types import SimpleNamespace
 from typing import List
 
 import pytest
 
+from jupyter_lsp import LanguageServerManager
+
 from ..virtual_documents_shadow import (
     EditableFile,
     ShadowFilesystemError,
@@ -93,9 +97,16 @@ def shadow_path(tmpdir):
 
 @pytest.fixture
 def manager():
-    return SimpleNamespace(
-        language_servers={"python-lsp-server": {"requires_documents_on_disk": True}}
-    )
+    manager = LanguageServerManager()
+    manager.language_servers = {
+        "python-lsp-server": {
+            "requires_documents_on_disk": True,
+            "argv": [],
+            "languages": ["python"],
+            "version": 2,
+        }
+    }
+    return manager
 
 
 @pytest.mark.asyncio
@@ -198,3 +209,43 @@ def run_shadow(message):
                 "params": {"textDocument": {"uri": ok_file_uri}},
             }
         )
+
+
+@pytest.fixture
+def forbidden_shadow_path(tmpdir):
+    path = Path(tmpdir) / "no_permission_dir"
+    path.mkdir(mode=0)
+
+    yield path
+
+    # re-adjust the permissions, see https://github.com/pytest-dev/pytest/issues/7821
+    path.chmod(0o755)
+
+
+@pytest.mark.asyncio
+async def test_io_failure(forbidden_shadow_path, manager, caplog):
+    file_uri = (forbidden_shadow_path / "test.py").as_uri()
+
+    shadow = setup_shadow_filesystem(forbidden_shadow_path.as_uri())
+
+    def send_change():
+        message = did_open(file_uri, "content")
+        return shadow("client", message, "python-lsp-server", manager)
+
+    with caplog.at_level(logging.WARNING):
+        assert await send_change() is None
+        assert await send_change() is None
+    # no message should be emitted during the first two attempts
+    assert caplog.text == ""
+
+    # a wargning should be emitted on third failure
+    with caplog.at_level(logging.WARNING):
+        assert await send_change() is None
+    assert "initialization of shadow filesystem failed three times" in caplog.text
+    assert "PermissionError" in caplog.text
+    caplog.clear()
+
+    # no message should be emitted in subsequent attempts
+    with caplog.at_level(logging.WARNING):
+        assert await send_change() is None
+    assert caplog.text == ""

python_packages/jupyter_lsp/jupyter_lsp/virtual_documents_shadow.py

@@ -111,6 +111,8 @@ def setup_shadow_filesystem(virtual_documents_uri: str):
         )
 
     initialized = False
+    failures = []
+
     shadow_filesystem = Path(file_uri_to_path(virtual_documents_uri))
 
     @lsp_message_listener("client")
@@ -145,12 +147,27 @@ async def shadow_virtual_documents(scope, message, language_server, manager):
 
         # initialization (/any file system operations) delayed until needed
         if not initialized:
-            # create if does no exist (so that removal does not raise)
-            shadow_filesystem.mkdir(parents=True, exist_ok=True)
-            # remove with contents
-            rmtree(str(shadow_filesystem))
-            # create again
-            shadow_filesystem.mkdir(parents=True, exist_ok=True)
+            if len(failures) == 3:
+                return
+            try:
+                # create if does no exist (so that removal does not raise)
+                shadow_filesystem.mkdir(parents=True, exist_ok=True)
+                # remove with contents
+                rmtree(str(shadow_filesystem))
+                # create again
+                shadow_filesystem.mkdir(parents=True, exist_ok=True)
+            except (OSError, PermissionError, FileNotFoundError) as e:
+                failures.append(e)
+                if len(failures) == 3:
+                    manager.log.warn(
+                        "[lsp] initialization of shadow filesystem failed three times"
+                        " check if the path set by `LanguageServerManager.virtual_documents_dir`"
+                        " or `JP_LSP_VIRTUAL_DIR` is correct; if this is happening with a server"
+                        " for which which you control (or wish to override) jupyter-lsp specification"
+                        " you can try switching `requires_documents_on_disk` off. The errors were: %s",
+                        failures,
+                    )
+                return
             initialized = True
 
         path = file_uri_to_path(uri)