Encode set, frozenset, bytearray, and iterators as json arrays

[onealj]

BPO	31155
Nosy	@rhettinger, @etrepum, @salty-horse, @methane, @onealj, @sedrubal
PRs	bpo-31155: Encode set, frozenset, bytearray, and iterators as json arrays #3034

^{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:

assignee = 'https://github.com/etrepum'
closed_at = <Date 2019-04-08.07:52:33.134>
created_at = <Date 2017-08-09.09:23:16.665>
labels = ['3.7', 'type-feature', 'library']
title = 'Encode set, frozenset, bytearray, and iterators as json arrays'
updated_at = <Date 2021-10-07.08:11:02.536>
user = 'https://github.com/onealj'

bugs.python.org fields:

activity = <Date 2021-10-07.08:11:02.536>
actor = 'sedrubal'
assignee = 'bob.ippolito'
closed = True
closed_date = <Date 2019-04-08.07:52:33.134>
closer = 'methane'
components = ['Library (Lib)']
creation = <Date 2017-08-09.09:23:16.665>
creator = 'javenoneal'
dependencies = []
files = []
hgrepos = []
issue_num = 31155
keywords = []
message_count = 4.0
messages = ['299981', '315782', '315789', '339597']
nosy_count = 6.0
nosy_names = ['rhettinger', 'bob.ippolito', 'salty-horse', 'methane', 'javenoneal', 'sedrubal']
pr_nums = ['3034']
priority = 'normal'
resolution = 'rejected'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue31155'
versions = ['Python 3.7']

[onealj]

Currently json.dump, json.dumps, and json.JSONEncoder do not support writing iterator objects. Users can choose to pass the iterator to a tuple and write that as a json array, but this is wasteful if the iterator is large, requiring a large amount of memory to be temporarily allocated for the tuple prior to json encoding.

The json module also does not support writing sets, frozensets, or bytearrays.

[salty-horse]

If sets are to be supported, then so should dictionary views.

Please also consider the range type.

[rhettinger]

There is some virtue to the current design. Having a user explicitly cast to a list will avoid unintentional conversions.

[methane]

I concur with Raymond.
If you really need this feature, please discuss on python-dev ML.