Fix empty cwd value for pylint

[Ultimator14]

Fixes #369

A shorter way to write this would be to use the walrus operator but that would require Python 3.8+ and the README states this project is Python 3.7+.

if not (cwd := document._workspace.root_path):
    cwd = os.path.dirname(__file__)

[ccordoba12]

@Ultimator14, thanks a lot for your contribution! Let me know if you need help to fix the linting issues reported by our CI.

[Ultimator14]

@ccordoba12 thanks, AFAICS pylint complains about too many if's and variables. I don't really know how to rewrite the commit with less of both. If you have an idea feel free to make the changes.

The only thing I can think of is editing some of the existing code to match the tests.
My ideas:
Too many branches

diff --git a/pylsp/plugins/pylint_lint.py b/pylsp/plugins/pylint_lint.py
index 7daaf18..464d3f1 100644
--- a/pylsp/plugins/pylint_lint.py
+++ b/pylsp/plugins/pylint_lint.py
@@ -156,13 +156,9 @@ class PylintLinter:
                 },
             }
 
-            if diag['type'] == 'convention':
+            if diag['type'] in ['convention', 'information']:
                 severity = lsp.DiagnosticSeverity.Information
-            elif diag['type'] == 'information':
-                severity = lsp.DiagnosticSeverity.Information
-            elif diag['type'] == 'error':
-                severity = lsp.DiagnosticSeverity.Error
-            elif diag['type'] == 'fatal':
+            elif diag['type'] in ['error', 'fatal']:
                 severity = lsp.DiagnosticSeverity.Error
             elif diag['type'] == 'refactor':
                 severity = lsp.DiagnosticSeverity.Hint

For 'Too many local variables' I don't find an unneeded variable. Maybe the whole code calling pylint could be moved to a separate function because the variables used there are not used again afterwards.

diff --git a/pylsp/plugins/pylint_lint.py b/pylsp/plugins/pylint_lint.py
index 464d3f1..5ee2f56 100644
--- a/pylsp/plugins/pylint_lint.py
+++ b/pylsp/plugins/pylint_lint.py
@@ -47,6 +47,35 @@ UNNECESSITY_CODES = {
 class PylintLinter:
     last_diags = collections.defaultdict(list)
 
+    @classmethod
+    def call_pylint(cls, document, flags):
+        cmd = [
+            sys.executable,
+            '-c',
+            'import sys; from pylint.lint import Run; Run(sys.argv[1:])',
+            '-f',
+            'json',
+            document.path
+        ] + (shlex.split(str(flags)) if flags else [])
+        log.debug("Calling pylint with '%s'", ' '.join(cmd))
+
+        cwd = document._workspace.root_path
+
+        if not cwd:
+            cwd = os.path.dirname(__file__)
+
+        with Popen(cmd, stdout=PIPE, stderr=PIPE,
+                   cwd=cwd, universal_newlines=True) as process:
+            process.wait()
+            json_out = process.stdout.read()
+            err = process.stderr.read()
+
+        if err != '':
+            log.error("Error calling pylint: '%s'", err)
+
+        return json_out
+
+
     @classmethod
     def lint(cls, document, is_saved, flags=''):
         """Plugin interface to pylsp linter.
@@ -85,29 +114,7 @@ class PylintLinter:
             # save.
             return cls.last_diags[document.path]
 
-        cmd = [
-            sys.executable,
-            '-c',
-            'import sys; from pylint.lint import Run; Run(sys.argv[1:])',
-            '-f',
-            'json',
-            document.path
-        ] + (shlex.split(str(flags)) if flags else [])
-        log.debug("Calling pylint with '%s'", ' '.join(cmd))
-
-        cwd = document._workspace.root_path
-
-        if not cwd:
-            cwd = os.path.dirname(__file__)
-
-        with Popen(cmd, stdout=PIPE, stderr=PIPE,
-                   cwd=cwd, universal_newlines=True) as process:
-            process.wait()
-            json_out = process.stdout.read()
-            err = process.stderr.read()
-
-        if err != '':
-            log.error("Error calling pylint: '%s'", err)
+        json_out = cls.call_pylint(document, flags)
 
         # pylint prints nothing rather than [] when there are no diagnostics.
         # json.loads will not parse an empty string, so just return.

[ccordoba12]

AFAICS pylint complains about too many if's and variables

Yep, but I think the easiest thing to do is to skip those warnings because I don't see the need to significantly change the code due to them.

[ccordoba12]

Thanks @Ultimator14 for your contribution!

I fixed the linting issues so we can merge your PR and release a new version.