#177: Forbid to use CRLF end-of-line

CHANGELOG.md

@@ -3,6 +3,13 @@
 We follow Semantic Versions.
 
 
+## Version 0.6.0
+
+### Features
+
+- Forbid to use `\r\n` (CRLF) end-of-line
+
+
 ## Version 0.5.0
 
 ### Features

dotenv_linter/checker.py

@@ -48,7 +48,10 @@ def run(self) -> None:
     def _prepare_file_contents(self) -> Iterator[Tuple[str, str]]:
         """Returns iterator with each file contents."""
         for filename in self._filenames:  # TODO: move this logic from here
-            with open(filename, encoding='utf8') as file_object:
+            # From `open` docs on `newline` - If it is '', universal
+            # newline mode is enabled but line endings are returned
+            # to the caller untranslated
+            with open(filename, encoding='utf8', newline='') as file_object:
                 yield filename, file_object.read()
 
     def _prepare_fst(

dotenv_linter/violations/values.py

@@ -8,6 +8,7 @@
 
 .. autoclass:: SpacedValueViolation
 .. autoclass:: QuotedValueViolation
+.. autoclass:: InvalidEOLViolation
 
 """
 
@@ -62,3 +63,24 @@ class QuotedValueViolation(BaseFSTViolation):
 
     code = 301
     error_template = 'Found quoted value'
+
+
+@final
+class InvalidEOLViolation(BaseFSTViolation):
+    r"""
+    Restricts to use `\r\n` (CRLF) end-of-line.
+
+    Reasoning:
+        Mixing different end-of-line chars can lead to different
+        hard-to-debug problems.
+
+    Solution:
+        Use `\n` (LF) end-of-line.
+        Another option is to add line `text eol=lf` to `.gitattributes`.
+
+    .. versionadded:: 0.6.0
+
+    """
+
+    code = 302
+    error_template = 'Found CRLF end-of-line'

dotenv_linter/visitors/fst/values.py

@@ -1,12 +1,15 @@
-from typing import final
+from typing import Final, final
 
 from dotenv_linter.grammar.fst import Value
 from dotenv_linter.violations.values import (
+    InvalidEOLViolation,
     QuotedValueViolation,
     SpacedValueViolation,
 )
 from dotenv_linter.visitors.base import BaseFSTVisitor
 
+CRLF_EOL: Final = '\r'
+
 
 @final
 class ValueVisitor(BaseFSTVisitor):
@@ -19,10 +22,13 @@ def visit_value(self, node: Value) -> None:
         Raises:
             QuotedValueViolation
             SpacedValueViolation
+            InvalidEOLViolation
 
         """
         self._check_value_quotes(node)
         self._check_value_spaces(node)
+        self._is_crlf_eol_used(node)
+
         self.generic_visit(node)
 
     def _check_value_spaces(self, node: Value) -> None:
@@ -35,3 +41,7 @@ def _check_value_quotes(self, node: Value) -> None:
             self._add_violation(QuotedValueViolation(node, text=node.raw_text))
         elif text.startswith("'") and text.endswith("'"):
             self._add_violation(QuotedValueViolation(node, text=node.raw_text))
+
+    def _is_crlf_eol_used(self, node: Value) -> None:
+        if node.raw_text.endswith(CRLF_EOL):
+            self._add_violation(InvalidEOLViolation(node, text=node.text))

tests/fixtures/.env.correct

@@ -4,3 +4,4 @@
 # See: https://github.com/wemake-services/dotenv-linter/issues/20
 TEST=1
 EMPTY=
+VARIABLE_WITH_TRAILING_SLASH_R=value\r

tests/test_cli/test_lint_command.py

@@ -1,4 +1,7 @@
 import subprocess
+from pathlib import Path
+
+from dotenv_linter.violations.values import InvalidEOLViolation
 
 
 def test_lint_correct_fixture(fixture_path):
@@ -74,5 +77,26 @@ def test_lint_wrong_fixture(fixture_path, all_violations):
 
     assert process.returncode == 1
 
-    for violation_class in all_violations:
+    violations_without_eol = set(all_violations) - {InvalidEOLViolation}
+    for violation_class in violations_without_eol:
         assert str(violation_class.code) in stderr
+
+
+def test_lint_wrong_eol(tmp_path: Path) -> None:
+    """Checks that `lint` command works for with with CRLF end-of-line."""
+    temp_file = tmp_path / '.env.temp'
+    temp_file.write_text('VARIABLE_WITH_CRLF_EOL=123\r\n')
+
+    process = subprocess.Popen(
+        ['dotenv-linter', temp_file.absolute()],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        # It is important to set this to `False`, otherwise eol are normalized
+        universal_newlines=False,
+        encoding='utf8',
+    )
+    _, stderr = process.communicate()
+
+    assert process.returncode == 1
+
+    assert str(InvalidEOLViolation.code) in stderr