Remove ValueError if compact=expand=True, compact takes precendence

Author: hugovk

Doc/library/pprint.rst

@@ -70,13 +70,13 @@ Functions
       each item of a sequence will be formatted on a separate line,
       otherwise as many items as will fit within the *width*
       will be formatted on each output line.
-      Incompatible with *expand*.
+      Takes precedence over *expand*.
 
    :param bool expand:
-      If ``True``,
+      If ``True`` (the default),
       opening parentheses and brackets will be followed by a newline and the
       following content will be indented by one level, similar to
-      pretty-printed JSON. Incompatible with *compact*.
+      pretty-printed JSON. Has no effect when *compact* is also ``True``.
 
    :param bool sort_dicts:
       If ``True``, dictionaries will be formatted with
@@ -222,7 +222,9 @@ PrettyPrinter objects
 
    .. versionchanged:: next
       Changed default *indent* from 1 to 4,
-      and default *width* from 80 to 88.
+      default *width* from 80 to 88,
+      and default *expand* from ``False`` to ``True``.
+      *compact* takes precedence over *expand* when both are ``True``.
 
 
 :class:`PrettyPrinter` instances have the following methods:

Lib/pprint.py

@@ -159,12 +159,12 @@ def __init__(
 
         compact
             If true, several items will be combined in one line.
-            Incompatible with expand mode.
+            Takes precedence over expand mode.
 
         expand
             If true, the output will be formatted similar to
             pretty-printed json.dumps() when ``indent`` is supplied.
-            Incompatible with compact mode.
+            Has no effect if compact mode is also enabled.
 
         sort_dicts
             If true, dict keys are sorted.
@@ -181,8 +181,6 @@ def __init__(
             raise ValueError('depth must be > 0')
         if not width:
             raise ValueError('width must be != 0')
-        if compact and expand:
-            raise ValueError('compact and expand are incompatible')
         self._depth = depth
         self._indent_per_level = indent
         self._width = width
@@ -191,7 +189,7 @@ def __init__(
         else:
             self._stream = _sys.stdout
         self._compact = bool(compact)
-        self._expand = bool(expand)
+        self._expand = bool(expand) and not self._compact
         self._sort_dicts = sort_dicts
         self._underscore_numbers = underscore_numbers
 

Lib/test/test_pprint.py

@@ -169,7 +169,6 @@ def test_init(self):
         self.assertRaises(ValueError, pprint.PrettyPrinter, depth=0)
         self.assertRaises(ValueError, pprint.PrettyPrinter, depth=-1)
         self.assertRaises(ValueError, pprint.PrettyPrinter, width=0)
-        self.assertRaises(ValueError, pprint.PrettyPrinter, compact=True, expand=True)
 
     def test_basic(self):
         # Verify .isrecursive() and .isreadable() w/o recursion
@@ -1164,6 +1163,14 @@ def test_compact(self):
  [0, 1, 2, 3, 4]]"""
         self.assertEqual(_pformat(o, width=47, compact=True), expected)
 
+    def test_compact_without_explicit_expand(self):
+        # Passing compact=True alone should not require also passing
+        # expand=False, even though expand defaults to True.
+        self.assertEqual(
+            pprint.pformat([1, 2, 3, 4, 5], width=10, compact=True),
+            "[   1, 2,\n    3, 4,\n    5]",
+        )
+
     def test_compact_width(self):
         levels = 20
         number = 10