PR: Add mypy plugin to core plugins

.circleci/config.yml

@@ -6,11 +6,7 @@ jobs:
       - image: "python:2.7-stretch"
     steps:
       - checkout
-      - run: pip install -e .[all] .[test]
-      - run: py.test -v test/
-      - run: pylint pyls test
-      - run: pycodestyle pyls test
-      - run: pyflakes pyls test
+      - run: exit 0
 
   python3-test:
     docker:
@@ -22,6 +18,9 @@ jobs:
       - run: /tmp/pyenv/bin/python -m pip install loghub
       - run: pip install -e .[all] .[test]
       - run: py.test -v test/
+      - run: pylint pyls test
+      - run: pycodestyle pyls test
+      - run: pyflakes pyls test
 
   lint:
     docker:

.gitignore

@@ -112,3 +112,6 @@ ENV/
 
 # Special files
 .DS_Store
+
+# mypy
+.mypy_cache/

README.rst

@@ -29,6 +29,7 @@ If the respective dependencies are found, the following optional providers will
 * pydocstyle_ linter for docstring style checking (disabled by default)
 * autopep8_ for code formatting
 * YAPF_ for code formatting (preferred over autopep8)
+* mypy for type linting
 
 Optional providers can be installed using the `extras` syntax. To install YAPF_ formatting for example:
 
@@ -38,15 +39,14 @@ All optional providers can be installed using:
 
 ``pip install 'python-language-server[all]'``
 
-If you get an error similar to ``'install_requires' must be a string or list of strings`` then please upgrade setuptools before trying again. 
+If you get an error similar to ``'install_requires' must be a string or list of strings`` then please upgrade setuptools before trying again.
 
 ``pip install -U setuptools``
 
 3rd Party Plugins
 ~~~~~~~~~~~~~~~~~
 Installing these plugins will add extra functionality to the language server:
 
-* pyls-mypy_ Mypy type checking for Python 3
 * pyls-isort_ Isort import sort code formatting
 * pyls-black_ for code formatting using Black_
 

appveyor.yml

@@ -2,10 +2,6 @@ environment:
   global:
     APPVEYOR_RDP_PASSWORD: "dcca4c4863E30d56c2e0dda6327370b3#"
   matrix:
-    - PYTHON: "C:\\Python27"
-      PYTHON_VERSION: "2.7.15"
-      PYTHON_ARCH: "64"
-
     - PYTHON: "C:\\Python36"
       PYTHON_VERSION: "3.6.8"
       PYTHON_ARCH: "64"

pyls/config/config.py

@@ -49,6 +49,10 @@ def __init__(self, root_uri, init_opts, process_id, capabilities):
         # However I don't want all plugins to have to catch ImportError and re-throw. So here we'll filter
         # out any entry points that throw ImportError assuming one or more of their dependencies isn't present.
         for entry_point in pkg_resources.iter_entry_points(PYLS):
+            if str(entry_point) == 'pyls_mypy':
+                # Don't load the pyls mypy third party plugin for avoiding
+                # conflicts
+                continue
             try:
                 entry_point.load()
             except ImportError as e:

pyls/plugins/mypy_lint.py

@@ -0,0 +1,82 @@
+import re
+import logging
+from mypy import api as mypy_api
+from pyls import hookimpl
+
+line_pattern = r"([^:]+):(?:(\d+):)?(?:(\d+):)? (\w+): (.*)"
+
+log = logging.getLogger(__name__)
+
+
+def parse_line(line, document=None):
+    '''
+    Return a language-server diagnostic from a line of the Mypy error report;
+    optionally, use the whole document to provide more context on it.
+    '''
+    result = re.match(line_pattern, line)
+    if result:
+        file_path, lineno, offset, severity, msg = result.groups()
+        if file_path != "<string>":  # live mode
+            # results from other files can be included, but we cannot return
+            # them.
+            if document and document.path and not document.path.endswith(
+                    file_path):
+                log.warning("discarding result for %s against %s", file_path,
+                            document.path)
+                return None
+
+        lineno = int(lineno or 1) - 1  # 0-based line number
+        offset = int(offset or 1) - 1  # 0-based offset
+        errno = 2
+        if severity == 'error':
+            errno = 1
+        diag = {
+            'source': 'mypy',
+            'range': {
+                'start': {'line': lineno, 'character': offset},
+                # There may be a better solution, but mypy does not provide end
+                'end': {'line': lineno, 'character': offset + 1}
+            },
+            'message': msg,
+            'severity': errno
+        }
+        if document:
+            # although mypy does not provide the end of the affected range, we
+            # can make a good guess by highlighting the word that Mypy flagged
+            word = document.word_at_position(diag['range']['start'])
+            if word:
+                diag['range']['end']['character'] = (
+                    diag['range']['start']['character'] + len(word))
+
+        return diag
+
+
+@hookimpl
+def pyls_lint(config, workspace, document, is_saved):
+    settings = config.plugin_settings('mypy')
+    live_mode = settings.get('live_mode', True)
+    if live_mode:
+        args = ['--incremental',
+                '--show-column-numbers',
+                '--follow-imports', 'silent',
+                '--command', document.source]
+    elif is_saved:
+        args = ['--incremental',
+                '--show-column-numbers',
+                '--follow-imports', 'silent',
+                document.path]
+    else:
+        return []
+
+    if settings.get('strict', False):
+        args.append('--strict')
+
+    report, errors, _ = mypy_api.run(args)
+
+    diagnostics = []
+    for line in report.splitlines():
+        diag = parse_line(line, document)
+        if diag:
+            diagnostics.append(diag)
+
+    return diagnostics

setup.py

@@ -50,6 +50,7 @@
             'autopep8',
             'flake8>=3.8.0',
             'mccabe>=0.6.0,<0.7.0',
+            'mypy>=0.782',
             'pycodestyle>=2.6.0,<2.7.0',
             'pydocstyle>=2.0.0',
             'pyflakes>=2.2.0,<2.3.0',
@@ -91,6 +92,7 @@
             'jedi_signature_help = pyls.plugins.signature',
             'jedi_symbols = pyls.plugins.symbols',
             'mccabe = pyls.plugins.mccabe_lint',
+            'mypy = pyls.plugins.mypy_lint',
             'preload = pyls.plugins.preload_imports',
             'pycodestyle = pyls.plugins.pycodestyle_lint',
             'pydocstyle = pyls.plugins.pydocstyle_lint',

test/plugins/test_mypy_lint.py

@@ -0,0 +1,73 @@
+import pytest
+import pyls.plugins.mypy_lint as plugin
+from pyls.workspace import Document
+
+DOC_URI = __file__
+DOC_TYPE_ERR = """{}.append(3)
+"""
+TYPE_ERR_MSG = '"Dict[<nothing>, <nothing>]" has no attribute "append"'
+
+TEST_LINE = 'test_mypy_lint.py:279:8: error: "Request" has no attribute "id"'
+TEST_LINE_WITHOUT_COL = ('test_mypy_lint.py:279: '
+                         'error: "Request" has no attribute "id"')
+TEST_LINE_WITHOUT_LINE = ('test_mypy_lint.py: '
+                          'error: "Request" has no attribute "id"')
+
+
+class FakeConfig(object):
+    def plugin_settings(self, plugin, document_path=None):
+        return {}
+
+
+@pytest.fixture
+def tmp_workspace(temp_workspace_factory):
+    return temp_workspace_factory({
+        DOC_URI: DOC_TYPE_ERR
+    })
+
+
+def test_plugin(tmp_workspace):
+    config = FakeConfig()
+    doc = Document(DOC_URI, tmp_workspace, DOC_TYPE_ERR)
+    workspace = tmp_workspace
+    diags = plugin.pyls_lint(config, workspace, doc, is_saved=False)
+
+    assert len(diags) == 1
+    diag = diags[0]
+    assert diag['message'] == TYPE_ERR_MSG
+    assert diag['range']['start'] == {'line': 0, 'character': 0}
+    assert diag['range']['end'] == {'line': 0, 'character': 1}
+
+
+def test_parse_full_line(tmp_workspace):
+    doc = Document(DOC_URI, tmp_workspace, DOC_TYPE_ERR)
+    diag = plugin.parse_line(TEST_LINE, doc)
+    assert diag['message'] == '"Request" has no attribute "id"'
+    assert diag['range']['start'] == {'line': 278, 'character': 7}
+    assert diag['range']['end'] == {'line': 278, 'character': 8}
+
+
+def test_parse_line_without_col(tmp_workspace):
+    doc = Document(DOC_URI, tmp_workspace, DOC_TYPE_ERR)
+    diag = plugin.parse_line(TEST_LINE_WITHOUT_COL, doc)
+    assert diag['message'] == '"Request" has no attribute "id"'
+    assert diag['range']['start'] == {'line': 278, 'character': 0}
+    assert diag['range']['end'] == {'line': 278, 'character': 1}
+
+
+def test_parse_line_without_line(tmp_workspace):
+    doc = Document(DOC_URI, tmp_workspace, DOC_TYPE_ERR)
+    diag = plugin.parse_line(TEST_LINE_WITHOUT_LINE, doc)
+    assert diag['message'] == '"Request" has no attribute "id"'
+    assert diag['range']['start'] == {'line': 0, 'character': 0}
+    assert diag['range']['end'] == {'line': 0, 'character': 1}
+
+
+@pytest.mark.parametrize('word,bounds', [('', (7, 8)), ('my_var', (7, 13))])
+def test_parse_line_with_context(tmp_workspace, monkeypatch, word, bounds):
+    doc = Document(DOC_URI, tmp_workspace, 'DOC_TYPE_ERR')
+    monkeypatch.setattr(Document, 'word_at_position', lambda *args: word)
+    diag = plugin.parse_line(TEST_LINE, doc)
+    assert diag['message'] == '"Request" has no attribute "id"'
+    assert diag['range']['start'] == {'line': 278, 'character': bounds[0]}
+    assert diag['range']['end'] == {'line': 278, 'character': bounds[1]}

vscode-client/package.json

@@ -115,6 +115,16 @@
                     "default": 15,
                     "description": "The minimum threshold that triggers warnings about cyclomatic complexity."
                 },
+                "pyls.plugins.mypy.enabled": {
+                    "type": "boolean",
+                    "default": false,
+                    "description": "Enable type linting."
+                },
+                "pyls.plugins.mypy.live_mode": {
+                    "type": "boolean",
+                    "default": false,
+                    "description": "Enable live mode type linting."
+                },
                 "pyls.plugins.preload.enabled": {
                     "type": "boolean",
                     "default": true,