Handle duplicates in docstrings.

Author: domdfcoding

flake8_params/__init__.py

@@ -28,7 +28,7 @@
 
 # stdlib
 import ast
-from typing import Iterator, List, Optional, Union
+from typing import Counter, Iterator, List, Optional, Union
 
 # 3rd party
 import flake8_helper
@@ -123,7 +123,12 @@ def check_params(
 	signature_set = set(signature_args)
 	docstring_set = set(docstring_args)
 	if signature_set == docstring_set:
-		# Wrong order
+		# Wrong order or duplicated
+		docstring_counts = {k: v for k, v in Counter(docstring_set).items() if v > 1}
+
+		if docstring_counts:
+			return PRM003 + ": " + ' '.join(sorted(docstring_counts.keys()))
+
 		return PRM001
 	elif signature_set - docstring_set:
 		# Extras in signature

tests/example_code.py

@@ -399,3 +399,12 @@ def another_command(foo):
 	"""
 	Command line entry point.
 	"""
+
+
+def duplicated_params(tree: list) -> None:
+	"""
+	Does something.
+
+	:param tree:
+	:param tree:
+	"""

tests/test_flake8_params_/test_plugin.txt

@@ -19,3 +19,4 @@
 311:0: PRM002 Missing parameters in docstring: **baz
 356:1: PRM002 Missing parameters in docstring: a b c
 372:1: PRM002 Missing parameters in docstring: swallow
+404:0: PRM001 Docstring parameters in wrong order.