Faulty dict arg gives ValueError but mostly TypeError

[tomnor]

BPO	40329
Nosy	@serhiy-storchaka

^{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 = None
closed_at = <Date 2020-04-19.14:51:55.945>
created_at = <Date 2020-04-19.14:39:04.820>
labels = ['3.7', 'invalid', 'type-bug', 'library']
title = 'Faulty dict arg gives ValueError but mostly TypeError'
updated_at = <Date 2020-04-19.18:59:46.783>
user = 'https://bugs.python.org/tomnor'

bugs.python.org fields:

activity = <Date 2020-04-19.18:59:46.783>
actor = 'tomnor'
assignee = 'none'
closed = True
closed_date = <Date 2020-04-19.14:51:55.945>
closer = 'serhiy.storchaka'
components = ['Library (Lib)']
creation = <Date 2020-04-19.14:39:04.820>
creator = 'tomnor'
dependencies = []
files = []
hgrepos = []
issue_num = 40329
keywords = []
message_count = 3.0
messages = ['366781', '366783', '366799']
nosy_count = 2.0
nosy_names = ['serhiy.storchaka', 'tomnor']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue40329'
versions = ['Python 3.7']

[tomnor]

Hello Python bug tracker

Trying to create a dict with a top level set pair will fail, but how
will it fail?

Here comes a terminal session to reproduce the behavior. The same
command is just repeated.

----------------------------------8<----------------------------------

$ python3 -c 'd = dict({1, "one"})'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
TypeError: cannot convert dictionary update sequence element #0 to a sequence

# Understand, can't convert 1 to sequence.

$ python3 -c 'd = dict({1, "one"})'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ValueError: dictionary update sequence element #0 has length 3; 2 is required

# Not so helpful to me, don't understand.

$ python3 -c 'd = dict({1, "one"})'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
TypeError: cannot convert dictionary update sequence element #0 to a sequence

# OK, thanks

$ python3 -c 'd = dict({1, "one"})'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
TypeError: cannot convert dictionary update sequence element #0 to a sequence

$ python3 -c 'd = dict({1, "one"})'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
TypeError: cannot convert dictionary update sequence element #0 to a sequence

$ python3 -c 'd = dict({1, "one"})'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ValueError: dictionary update sequence element #0 has length 3; 2 is required

# Again?
---------------------------------->8----------------------------------

I searched the bug tracker on "dict typeerror valueerror" but couldn't
find something similar. What do you think about this?

$ python3 --version
Python 3.7.3

Best regards

Tomas

[serhiy-storchaka]

It is all correct. Note that set is unordered, so "element #0" can be 1, and can be "one". If it is 1, you get a type error. If it is "one", which is a sequence with length 3, you get a value error.

[tomnor]

Serhiy Storchaka <report@bugs.python.org> writes:

Serhiy Storchaka <storchaka+cpython@gmail.com> added the comment:

It is all correct. Note that set is unordered, so "element #0" can be 1, and can be "one". If it is 1, you get a type error. If it is "one", which is a sequence with length 3, you get a value error.

Yes! Thanks, sorry for the noise.