gh-100335 Use correct default attrs for Dialect

Author: shoeffner

Lib/csv.py

@@ -96,14 +96,14 @@ class Dialect:
     _name = ""
     _valid = False
     # placeholders
-    delimiter = None
-    quotechar = None
+    delimiter = ','
+    quotechar = '"'
     escapechar = None
-    doublequote = None
-    skipinitialspace = None
-    lineterminator = None
-    quoting = None
-    strict = None
+    doublequote = True
+    skipinitialspace = False
+    lineterminator = '\r\n'
+    quoting = QUOTE_MINIMAL
+    strict = False
 
     def __init__(self):
         if self.__class__ != Dialect:

Lib/test/test_csv.py

@@ -138,6 +138,18 @@ def _test_kw_attrs(self, ctor, *args):
         self.assertIs(obj.dialect.skipinitialspace, True)
         self.assertIs(obj.dialect.strict, True)
 
+    def test_default_attrs(self):
+        class dialect(csv.Dialect):
+            pass
+        self.assertEqual(dialect.delimiter, ',')
+        self.assertEqual(dialect.doublequote, True)
+        self.assertEqual(dialect.escapechar, None)
+        self.assertEqual(dialect.lineterminator, '\r\n')
+        self.assertEqual(dialect.quotechar, '"')
+        self.assertEqual(dialect.quoting, csv.QUOTE_MINIMAL)
+        self.assertEqual(dialect.skipinitialspace, False)
+        self.assertEqual(dialect.strict, False)
+
     def test_reader_kw_attrs(self):
         self._test_kw_attrs(csv.reader, [])
 
@@ -616,6 +628,7 @@ class mydialect(csv.Dialect):
     def test_incomplete_dialect(self):
         class myexceltsv(csv.Dialect):
             delimiter = "\t"
+            quoting = None
         self.assertRaises(csv.Error, myexceltsv)
 
     def test_space_dialect(self):

Misc/NEWS.d/next/Library/2022-12-18-21-57-36.gh-issue-100335.89i6HX.rst

@@ -0,0 +1,2 @@
+Set the attribute values of :class:`csv.Dialect` to their documented
+defaults, see :ref:`csv-fmt-params`.