Emit warning if a string is passed to PathPlus.write_lines

Author: domdfcoding

domdf_python_tools/paths.py

@@ -56,6 +56,7 @@
 import sys
 import tempfile
 import urllib.parse
+import warnings
 from collections import defaultdict, deque
 from operator import methodcaller
 from typing import (
@@ -532,6 +533,12 @@ def write_lines(
 		.. versionchanged:: 2.4.0  Added the ``trailing_whitespace`` option.
 		"""
 
+		if isinstance(data, str):
+			warnings.warn(
+					"Passing a string to PathPlus.write_lines writes each character to its own line.\n"
+					"That probably isn't what you intended."
+					)
+
 		if trailing_whitespace:
 			data = list(data)
 			if data[-1].strip():

tests/test_paths.py

@@ -521,6 +521,11 @@ def test_write_lines(tmp_pathplus):
 	content = tmp_file.read_text()
 	assert content == "this\nis\na\nlist\nof\nwords\nto\nwrite\nto\nthe\nfile\n"
 
+	with pytest.warns(UserWarning, match="Passing a string to PathPlus.write_lines writes each character to its own line."):
+		tmp_file.write_lines("abcdefg")
+	
+	assert tmp_file.read_text() == "a\nb\nc\nd\ne\nf\ng\n"
+
 
 def test_write_lines_trailing_whitespace(tmp_pathplus: PathPlus):
 	tmp_file = tmp_pathplus / "test.txt"