Add a rule to prohibit (and fix) trailing whitespace

Author: ralphbean

.pre-commit-config.yaml

@@ -3,6 +3,7 @@ repos:
     rev: v5.0.0
     hooks:
     -   id: trailing-whitespace
+        exclude: ^tests/resources/trailing_whitespace_input.txt$
     -   id: check-yaml
     -   id: double-quote-string-fixer
 -   repo: https://github.com/asottile/setup-cfg-fmt

README.md

@@ -9,6 +9,7 @@ gitlab-codeowners-linter makes sure that the CODEOWNERS file is formatted respec
   - there must be no empty lines between paths
   - paths must exist
   - there must not be duplicated sections
+  - there must not be trailing whitespace
 
 The linter can run in check or autofix mode.
 

gitlab_codeowners_linter/autofix.py

@@ -144,14 +144,15 @@ def _update_codeowners_file(codeowners_data, file_path):
                 f.write('\n')
             if section.comments:
                 for comment_line in section.comments:
-                    f.write(f'{comment_line}\n')
+                    f.write(f'{comment_line.rstrip()}\n')
             if section.codeowner_section != DEFAULT_SECTION:
-                f.write(f'{section.codeowner_section}')
+                f.write(f'{section.codeowner_section.rstrip()}')
             if section.entries:
                 f.write('\n')
                 for entry in section.entries:
                     if entry.comments:
                         for comment_line in entry.comments:
-                            f.write(f'{comment_line}\n')
+                            f.write(f'{comment_line.rstrip()}\n')
                     owners = ' '.join(str(x) for x in entry.owners)
-                    f.write(f'{entry.path} {owners}\n')
+                    line_to_write = f'{entry.path} {owners}'
+                    f.write(f'{line_to_write.rstrip()}\n')

gitlab_codeowners_linter/checks.py

@@ -19,14 +19,24 @@ def __init__(self):
         self.sections_with_non_existing_paths = []
         self.non_existing_paths = {}
         self.duplicated_sections = []
+        self.lines_with_trailing_whitespace = []
 
 
-def check(codeowners_data):
+def check(codeowners_data, file_path):
     violations = CodeownersViolations()
 
     if _is_codeowners_empty(codeowners_data):
         return violations
 
+    # Are there trailing whitespaces
+    violations.lines_with_trailing_whitespace = _get_lines_with_trailing_whitespace(
+        file_path,
+    )
+    if violations.lines_with_trailing_whitespace:
+        violations.violation_error_messages.append(
+            f'Lines with trailing whitespace: {violations.lines_with_trailing_whitespace}',
+        )
+
     # Are custom section names sorted?
     sort_sections_names_key = cmp_to_key(sort_section_names)
     if codeowners_data[1:] != sorted(codeowners_data[1:], key=sort_sections_names_key):
@@ -82,6 +92,15 @@ def _is_codeowners_empty(codeowners_data):
     return empty
 
 
+def _get_lines_with_trailing_whitespace(file_path):
+    lines_with_trailing_whitespace = []
+    with open(file_path) as f:
+        for i, line in enumerate(f, 1):
+            if line.endswith(' \n') or line.endswith('\t\n'):
+                lines_with_trailing_whitespace.append(i)
+    return lines_with_trailing_whitespace
+
+
 def _get_duplicated_sections(codeowners_data):
     all_sections_name = list(
         section.codeowner_section for section in codeowners_data)

gitlab_codeowners_linter/codeowners_linter.py

@@ -7,6 +7,7 @@
 #   - paths in a section must be unique
 #   - paths must exist
 #   - there must be no duplicated sections
+#   - there must not be trailing whitespace
 #
 from __future__ import annotations
 
@@ -32,7 +33,7 @@ def __init__(self, file_path, no_autofix):
         self.autofix = not no_autofix
 
     def lint(self):
-        violations = check(self.codeowners_data)
+        violations = check(self.codeowners_data, self.file_path)
         if self.autofix:
             fix(self.codeowners_data, violations, self.file_path)
         return violations

tests/codeowners_linter_tests.py

@@ -387,6 +387,20 @@ class TestCase:
                     'resources/empty_autofix.txt',
                 ),
             ),
+            TestCase(
+                name='trailing_whitespace',
+                input=os.path.join(
+                    os.path.dirname(os.path.abspath(__file__)),
+                    'resources/trailing_whitespace_input.txt',
+                ),
+                expected_check=[
+                    'Lines with trailing whitespace: [6, 8]',
+                ],
+                expected_fix=os.path.join(
+                    os.path.dirname(os.path.abspath(__file__)),
+                    'resources/trailing_whitespace_autofix.txt',
+                ),
+            ),
         ]
         for case in testcases:
             actual = os.path.join(

tests/resources/trailing_whitespace_autofix.txt

@@ -0,0 +1,9 @@
+### CODEOWNERS ###
+#
+# This is a test case for trailing whitespace
+#
+
+# comment with trailing whitespace
+[SECTION1]
+path1 @owner
+path2 @owner

tests/resources/trailing_whitespace_input.txt

@@ -0,0 +1,9 @@
+### CODEOWNERS ###
+#
+# This is a test case for trailing whitespace
+#
+
+# comment with trailing whitespace 
+[SECTION1]
+path1 @owner 
+path2 @owner