Unexpected behaviour when unpacking the outputs of a function returning a dictionary

[LucaGherardini]

Bug report

Bug description:

# Add a code block here, if required
def rec():
    return {'a': 1}

r, *_ = rec()
# r only contains 'a'
print(r)

r = rec()
# r is the full dictionary
print(r)

def rec():
    return {'a': 1}, None

r, *_ = rec()
# r is the full dictionary
print(r)

# expected behaviour: that r contains the full dictionary even when the unpacking operator (*_) is used, without the need to add an additional output 

CPython versions tested on:

3.14

Operating systems tested on:

macOS

[eendebakpt]

Iteration over a dict results in the keys. In your first example the result of rec() is {'a': 1}. When unpacking, the list of keys (e.g. ['a']) is unpacked. This is expected behaviour.

In the second example the result of rec() is a tuple with two elements ( {'a': 1}, None). Unpacking gives the full dictionary as the first element.

[LucaGherardini]

Yes, I think I misunderstood the nature of the unpacking operator. Thank you for addressing my concern.