Extend pylint linting integration (#539)

Author: ExpectationMax

pyls/plugins/pylint_lint.py

@@ -2,12 +2,16 @@
 """Linter plugin for pylint."""
 import collections
 import json
+import logging
 import sys
 
 from pylint.epylint import py_run
 from pyls import hookimpl, lsp
 
 
+log = logging.getLogger(__name__)
+
+
 class PylintLinter(object):
     last_diags = collections.defaultdict(list)
 
@@ -55,14 +59,21 @@ def lint(cls, document, is_saved, flags=''):
         path = document.path
         if sys.platform.startswith('win'):
             path = path.replace('\\', '/')
-        out, _err = py_run(
-            '{} -f json {}'.format(path, flags), return_std=True
-        )
+
+        pylint_call = '{} -f json {}'.format(path, flags)
+        log.debug("Calling pylint with '%s'", pylint_call)
+        json_out, err = py_run(pylint_call, return_std=True)
+
+        # Get strings
+        json_out = json_out.getvalue()
+        err = err.getvalue()
+
+        if err != '':
+            log.error("Error calling pylint: '%s'", err)
 
         # pylint prints nothing rather than [] when there are no diagnostics.
         # json.loads will not parse an empty string, so just return.
-        json_str = out.getvalue()
-        if not json_str.strip():
+        if not json_out.strip():
             cls.last_diags[document.path] = []
             return []
 
@@ -88,24 +99,21 @@ def lint(cls, document, is_saved, flags=''):
         #  * refactor
         #  * warning
         diagnostics = []
-        for diag in json.loads(json_str):
+        for diag in json.loads(json_out):
             # pylint lines index from 1, pyls lines index from 0
             line = diag['line'] - 1
-            # But both index columns from 0
-            col = diag['column']
-
-            # It's possible that we're linting an empty file. Even an empty
-            # file might fail linting if it isn't named properly.
-            end_col = len(document.lines[line]) if document.lines else 0
 
             err_range = {
                 'start': {
                     'line': line,
-                    'character': col,
+                    # Index columns start from 0
+                    'character': diag['column'],
                 },
                 'end': {
                     'line': line,
-                    'character': end_col,
+                    # It's possible that we're linting an empty file. Even an empty
+                    # file might fail linting if it isn't named properly.
+                    'character': len(document.lines[line]) if document.lines else 0,
                 },
             }
 
@@ -131,6 +139,17 @@ def lint(cls, document, is_saved, flags=''):
         return diagnostics
 
 
+def _build_pylint_flags(settings):
+    """Build arguments for calling pylint."""
+    pylint_args = settings.get('args')
+    if pylint_args is None:
+        return ''
+    return ' '.join(pylint_args)
+
+
 @hookimpl
-def pyls_lint(document, is_saved):
-    return PylintLinter.lint(document, is_saved)
+def pyls_lint(config, document, is_saved):
+    settings = config.plugin_settings('pylint')
+    log.debug("Got pylint settings: %s", settings)
+    flags = _build_pylint_flags(settings)
+    return PylintLinter.lint(document, is_saved, flags=flags)

test/plugins/test_pylint_lint.py

@@ -38,9 +38,9 @@ def write_temp_doc(document, contents):
         temp_file.write(contents)
 
 
-def test_pylint():
+def test_pylint(config):
     with temp_document(DOC) as doc:
-        diags = pylint_lint.pyls_lint(doc, True)
+        diags = pylint_lint.pyls_lint(config, doc, True)
 
         msg = '[unused-import] Unused import sys'
         unused_import = [d for d in diags if d['message'] == msg][0]
@@ -49,22 +49,22 @@ def test_pylint():
         assert unused_import['severity'] == lsp.DiagnosticSeverity.Warning
 
 
-def test_syntax_error_pylint():
+def test_syntax_error_pylint(config):
     with temp_document(DOC_SYNTAX_ERR) as doc:
-        diag = pylint_lint.pyls_lint(doc, True)[0]
+        diag = pylint_lint.pyls_lint(config, doc, True)[0]
 
         assert diag['message'].startswith('[syntax-error] invalid syntax')
         # Pylint doesn't give column numbers for invalid syntax.
         assert diag['range']['start'] == {'line': 0, 'character': 0}
         assert diag['severity'] == lsp.DiagnosticSeverity.Error
 
 
-def test_lint_free_pylint():
+def test_lint_free_pylint(config):
     # Can't use temp_document because it might give us a file that doesn't
     # match pylint's naming requirements. We should be keeping this file clean
     # though, so it works for a test of an empty lint.
     assert not pylint_lint.pyls_lint(
-        Document(uris.from_fs_path(__file__)), True)
+        config, Document(uris.from_fs_path(__file__)), True)
 
 
 def test_lint_caching():
@@ -95,10 +95,10 @@ def test_lint_caching():
         assert not pylint_lint.PylintLinter.lint(doc, False, flags)
 
 
-def test_per_file_caching():
+def test_per_file_caching(config):
     # Ensure that diagnostics are cached per-file.
     with temp_document(DOC) as doc:
-        assert pylint_lint.pyls_lint(doc, True)
+        assert pylint_lint.pyls_lint(config, doc, True)
 
     assert not pylint_lint.pyls_lint(
-        Document(uris.from_fs_path(__file__)), False)
+        config, Document(uris.from_fs_path(__file__)), False)

vscode-client/package.json

@@ -225,6 +225,20 @@
                     "default": true,
                     "description": "Enable or disable the plugin."
                 },
+                "pyls.plugins.pylint.enabled": {
+                    "type": "boolean",
+                    "default": true,
+                    "description": "Enable or disable the plugin."
+                },
+                "pyls.plugins.pylint.args": {
+                    "type": "array",
+                    "default": null,
+                    "items": {
+                        "type": "string"
+                    },
+                    "uniqueItems": false,
+                    "description": "Arguments to pass to pylint."
+                },
                 "pyls.plugins.rope_completion.enabled": {
                     "type": "boolean",
                     "default": true,