fix: Strip virtual_documents_dir from filepath

Strip away jupyterlabs virtual documents directory from the
stdin-filename in order for ruff to be able to correctly find the
correct config settings (see #102).
Also adds the config option to set the virtual documents directory. If
not set, use `JP_LSP_VIRTUAL_DIR` or `.virtual_documents`.

Author: jhossbach

README.md

@@ -69,6 +69,7 @@ pylsp = {
       perFileIgnores = { ["__init__.py"] = "CPY001" },  -- Rules that should be ignored for specific files
       preview = false,  -- Whether to enable the preview style linting and formatting.
       targetVersion = "py310",  -- The minimum python version to target (applies for both linting and formatting).
+      virtualDocumentsDir = ".virtual_documents",  -- If using JupyterLab, point to the location of the virtual documents directory.
     },
   }
 }
@@ -104,6 +105,7 @@ pylsp = {
         },
         "preview": false,
         "targetVersion": "py310"
+        "virtualDocumentsDir": ".virtual_documents",
       }
     }
   }

pylsp_ruff/plugin.py

@@ -2,6 +2,7 @@
 import importlib.util
 import json
 import logging
+import os
 import re
 import shutil
 import sys
@@ -573,6 +574,24 @@ def run_ruff(
     return stdout.decode()
 
 
+def strip_virtual_documents_path(
+    document_path: str, virtual_documents_dir: Optional[str]
+) -> str:
+    """Strip the virtual documents path from the current document path.
+    Returns the unchanged document_path if virtual_documents_dir is not in the path.
+    """
+    if not virtual_documents_dir:
+        return document_path
+
+    virt_parts = PurePath(virtual_documents_dir).parts
+    parts = PurePath(document_path).parts
+    n = len(virt_parts)
+    for i in range(len(parts) - n + 1):
+        if parts[i : i + n] == virt_parts:
+            return str(PurePath(*parts[:i], *parts[i + n :]))
+    return document_path
+
+
 def build_check_arguments(
     document_path: str,
     settings: PluginSettings,
@@ -614,7 +633,9 @@ def build_check_arguments(
     args.append("--force-exclude")
     # Pass filename to ruff for per-file-ignores, catch unsaved
     if document_path != "":
-        args.append(f"--stdin-filename={document_path}")
+        args.append(
+            f"--stdin-filename={strip_virtual_documents_path(document_path, settings.virtual_documents_dir)}"
+        )
 
     if settings.config:
         args.append(f"--config={settings.config}")
@@ -692,7 +713,9 @@ def build_format_arguments(
     args.append("--force-exclude")
     # Pass filename to ruff for per-file-ignores, catch unsaved
     if document_path != "":
-        args.append(f"--stdin-filename={document_path}")
+        args.append(
+            f"--stdin-filename={strip_virtual_documents_path(document_path, settings.virtual_documents_dir)}"
+        )
 
     if settings.config:
         args.append(f"--config={settings.config}")
@@ -754,6 +777,11 @@ def load_settings(workspace: Workspace, document_path: str) -> PluginSettings:
         workspace.root_path, document_path, ["ruff.toml", ".ruff.toml"]
     )
 
+    if not plugin_settings.virtual_documents_dir:
+        plugin_settings.virtual_documents_dir = os.getenv(
+            "JP_LSP_VIRTUAL_DIR", ".virtual_documents"
+        )
+
     # Check if pyproject is present, ignore user settings if toml exists
     if config_in_pyproject or ruff_toml:
         log.debug("Found existing configuration for ruff, skipping pylsp config.")
@@ -768,6 +796,7 @@ def load_settings(workspace: Workspace, document_path: str) -> PluginSettings:
             format=plugin_settings.format,
             severities=plugin_settings.severities,
             unfixable=plugin_settings.unfixable,
+            virtual_documents_dir=plugin_settings.virtual_documents_dir,
         )
 
     return plugin_settings

pylsp_ruff/settings.py

@@ -33,6 +33,8 @@ class PluginSettings:
 
     target_version: Optional[str] = None
 
+    virtual_documents_dir: Optional[str] = None
+
 
 def to_camel_case(snake_str: str) -> str:
     components = snake_str.split("_")

tests/conftest.py

@@ -0,0 +1,52 @@
+import tempfile
+from unittest.mock import Mock
+
+import pytest
+from pylsp import uris
+from pylsp.config.config import Config
+from pylsp.workspace import Document, Workspace
+
+
+@pytest.fixture()
+def workspace(tmp_path):
+    """Return a workspace."""
+    ws = Workspace(tmp_path.absolute().as_uri(), Mock())
+    ws._config = Config(ws.root_uri, {}, 0, {})
+    return ws
+
+
+@pytest.fixture()
+def notebook_workspace(tmp_path):
+    """Workspace with a notebook and `ruff.toml`.
+
+    Structure created under `tmp_path`:
+        .
+        ├── .virtual_documents
+        │   └── foo
+        │       └── bar.ipynb
+        └── foo
+            ├── bar.ipynb
+            └── ruff.toml
+    """
+    virtual_dir = tmp_path / ".virtual_documents" / "foo"
+    real_dir = tmp_path / "foo"
+    virtual_dir.mkdir(parents=True)
+    real_dir.mkdir(parents=True)
+
+    (virtual_dir / "bar.ipynb").write_text("")
+    (real_dir / "bar.ipynb").write_text("")
+    (real_dir / "ruff.toml").write_text("")
+
+    ws = Workspace(tmp_path.absolute().as_uri(), Mock())
+    ws._config = Config(ws.root_uri, {}, 0, {})
+    return ws
+
+
+def temp_document(doc_text, workspace):
+    with tempfile.NamedTemporaryFile(
+        mode="w", dir=workspace.root_path, delete=False
+    ) as temp_file:
+        name = temp_file.name
+        temp_file.write(doc_text)
+    doc = Document(uris.from_fs_path(name), workspace)
+    return name, doc

tests/test_ruff_format.py

@@ -1,12 +1,11 @@
 import contextlib
-import tempfile
+import os
 import textwrap as tw
 from typing import Any, List, Mapping, Optional
-from unittest.mock import Mock
+from unittest.mock import patch
 
-import pytest
+from conftest import temp_document
 from pylsp import uris
-from pylsp.config.config import Config
 from pylsp.workspace import Document, Workspace
 
 import pylsp_ruff.plugin as plugin
@@ -47,24 +46,6 @@ def bar():
 ).strip()
 
 
-@pytest.fixture()
-def workspace(tmp_path):
-    """Return a workspace."""
-    ws = Workspace(tmp_path.absolute().as_uri(), Mock())
-    ws._config = Config(ws.root_uri, {}, 0, {})
-    return ws
-
-
-def temp_document(doc_text, workspace):
-    with tempfile.NamedTemporaryFile(
-        mode="w", dir=workspace.root_path, delete=False
-    ) as temp_file:
-        name = temp_file.name
-        temp_file.write(doc_text)
-    doc = Document(uris.from_fs_path(name), workspace)
-    return name, doc
-
-
 def run_plugin_format(workspace: Workspace, doc: Document) -> str:
     class TestResult:
         result: Optional[List[Mapping[str, Any]]]
@@ -106,6 +87,29 @@ def test_ruff_format_disabled(workspace):
     assert got == ""
 
 
+def test_ruff_format_strips_virtual_documents_path(notebook_workspace):
+    virtual_path = os.path.join(
+        notebook_workspace.root_path, ".virtual_documents", "foo", "bar.ipynb"
+    )
+    expected_stripped = os.path.join(notebook_workspace.root_path, "foo", "bar.ipynb")
+    doc_uri = uris.from_fs_path(virtual_path)
+    notebook_workspace.put_document(doc_uri, _UNFORMATTED_CODE)
+    doc = notebook_workspace.get_document(doc_uri)
+
+    with patch("pylsp_ruff.plugin.Popen") as popen_mock:
+        mock_instance = popen_mock.return_value
+        mock_instance.communicate.return_value = [bytes(), bytes()]
+        run_plugin_format(notebook_workspace, doc)
+
+    format_calls = [
+        call for call in popen_mock.call_args_list if "format" in call[0][0]
+    ]
+    assert format_calls, "ruff format was not invoked"
+    cmd = format_calls[0][0][0]
+    assert f"--stdin-filename={expected_stripped}" in cmd
+    assert f"--stdin-filename={virtual_path}" not in cmd
+
+
 def test_ruff_format_and_sort_imports(workspace):
     txt = f"{_UNSORTED_IMPORTS}\n{_UNFORMATTED_CODE}"
     want = f"{_SORTED_IMPORTS}\n\n\n{_FORMATTED_CODE}\n"

tests/test_ruff_lint.py

@@ -5,12 +5,11 @@
 import stat
 import sys
 import tempfile
-from unittest.mock import Mock, patch
+from unittest.mock import patch
 
-import pytest
 from pylsp import lsp, uris
-from pylsp.config.config import Config
-from pylsp.workspace import Document, Workspace
+from pylsp.workspace import Document
+from conftest import temp_document
 
 import pylsp_ruff.plugin as ruff_lint
 
@@ -29,24 +28,6 @@ def using_const():
 """
 
 
-@pytest.fixture()
-def workspace(tmp_path):
-    """Return a workspace."""
-    ws = Workspace(tmp_path.absolute().as_uri(), Mock())
-    ws._config = Config(ws.root_uri, {}, 0, {})
-    return ws
-
-
-def temp_document(doc_text, workspace):
-    with tempfile.NamedTemporaryFile(
-        mode="w", dir=workspace.root_path, delete=False
-    ) as temp_file:
-        name = temp_file.name
-        temp_file.write(doc_text)
-    doc = Document(uris.from_fs_path(name), workspace)
-    return name, doc
-
-
 def test_ruff_unsaved(workspace):
     doc = Document("", workspace, DOC)
     diags = ruff_lint.pylsp_lint(workspace, doc)
@@ -276,6 +257,38 @@ def f():
     os.unlink(os.path.join(workspace.root_path, "pyproject.toml"))
 
 
+def test_strip_virtual_documents_path_no_match():
+    path = "/work/foo/bar.py"
+    assert ruff_lint.strip_virtual_documents_path(path, ".virtual_documents") == path
+
+
+def test_strip_virtual_documents_path_empty():
+    path = "/work/.virtual_documents/foo/bar.ipynb"
+    assert ruff_lint.strip_virtual_documents_path(path, None) == path
+    assert ruff_lint.strip_virtual_documents_path(path, "") == path
+
+
+def test_ruff_lint_strips_virtual_documents_path(notebook_workspace):
+    virtual_path = os.path.join(
+        notebook_workspace.root_path, ".virtual_documents", "foo", "bar.ipynb"
+    )
+    expected_stripped = os.path.join(notebook_workspace.root_path, "foo", "bar.ipynb")
+    doc_uri = uris.from_fs_path(virtual_path)
+    notebook_workspace.put_document(doc_uri, "import os\n")
+    doc = notebook_workspace.get_document(doc_uri)
+
+    with patch("pylsp_ruff.plugin.Popen") as popen_mock:
+        mock_instance = popen_mock.return_value
+        mock_instance.communicate.return_value = [bytes(), bytes()]
+        ruff_lint.pylsp_lint(notebook_workspace, doc)
+
+    (call_args,) = popen_mock.call_args[0]
+    assert f"--stdin-filename={expected_stripped}" in call_args
+    assert (
+        f"--stdin-filename={virtual_path}" not in call_args
+    ), "virtual_documents prefix was not stripped"
+
+
 def test_notebook_input(workspace):
     doc_str = r"""
 print('hi')