PrettyPrinter cannot print dicts with unsortable keys

[7de15a01-df33-4df0-b6b5-81e09b8a0a1b]

BPO	7429
Nosy	@bitdancer, @MartinAltmayer

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields: ```python assignee = None closed_at = created_at = labels = ['type-bug', 'library'] title = 'PrettyPrinter cannot print dicts with unsortable keys' updated_at = user = 'https://github.com/MartinAltmayer' ``` bugs.python.org fields: ```python activity = actor = 'r.david.murray' assignee = 'none' closed = True closed_date = closer = 'r.david.murray' components = ['Library (Lib)'] creation = creator = 'MartinAltmayer' dependencies = [] files = [] hgrepos = [] issue_num = 7429 keywords = [] message_count = 3.0 messages = ['95939', '95942', '95953'] nosy_count = 3.0 nosy_names = ['LambertDW', 'r.david.murray', 'MartinAltmayer'] pr_nums = [] priority = 'normal' resolution = 'out of date' stage = None status = 'closed' superseder = None type = 'behavior' url = 'https://bugs.python.org/issue7429' versions = ['Python 3.1'] ```

[7de15a01-df33-4df0-b6b5-81e09b8a0a1b]

In the following code I use a class for dictionary-keys that has a __hash__-function but cannot be ordered and try to print that dictionary with a PrettyPrinter.

import pprint
pp = pprint.PrettyPrinter()

# A class that supports hashing and comparison for equality but cannot be ordered class KeyClass: def __init__(self,id): self.id = id

def \_\_eq__(self,other):
    return self.id == other.id

def \_\_ne__(self,other):
    return self.id != other.id

def \_\_hash__(self):
    return self.id

dictionary = dict.fromkeys([KeyClass(i) for i in range(10)])
pp.pprint(dictionary)

The script crashes with the following errors:

Traceback (most recent call last):
  File "/usr/local/lib/python3.1/pprint.py", line 272, in _safe_repr
    items = sorted(items)
TypeError: unorderable types: KeyClass() < KeyClass()

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "bug.py", line 20, in <module>
    pp.pprint(dictionary)
  File "/usr/local/lib/python3.1/pprint.py", line 106, in pprint
    self._format(object, self._stream, 0, 0, {}, 0)
  File "/usr/local/lib/python3.1/pprint.py", line 129, in _format
    rep = self._repr(object, context, level - 1)
  File "/usr/local/lib/python3.1/pprint.py", line 216, in _repr
    self._depth, level)
  File "/usr/local/lib/python3.1/pprint.py", line 228, in format
    return _safe_repr(object, context, maxlevels, level)
  File "/usr/local/lib/python3.1/pprint.py", line 277, in _safe_repr
    items = sorted(items, key=sortkey)
TypeError: unorderable types: KeyClass() < KeyClass()

[78a6bf11-a01d-46d5-ba37-0e5218983f8f]

I believe this issue was resolved---expect it in a future release.

[bitdancer]

Confirmed, it is fixed on all maintained branches. So the fix will be in 3.1.2, which should be in a month or so.