Variables in locals scope fails to be printed.

[xxm]

BPO	43507
Nosy	@mdickinson
Superseder	bpo-24800: exec docs should note that the no argument form in a local scope is really the two argument form

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

Show more details

GitHub fields:

assignee = None
closed_at = <Date 2021-03-16.10:41:20.143>
created_at = <Date 2021-03-16.03:08:01.278>
labels = ['interpreter-core', 'type-bug', '3.9']
title = 'Variables in locals scope fails to be printed.'
updated_at = <Date 2021-03-16.10:41:20.142>
user = 'https://bugs.python.org/xxm'

bugs.python.org fields:

activity = <Date 2021-03-16.10:41:20.142>
actor = 'mark.dickinson'
assignee = 'none'
closed = True
closed_date = <Date 2021-03-16.10:41:20.143>
closer = 'mark.dickinson'
components = ['Interpreter Core']
creation = <Date 2021-03-16.03:08:01.278>
creator = 'xxm'
dependencies = []
files = []
hgrepos = []
issue_num = 43507
keywords = []
message_count = 2.0
messages = ['388802', '388825']
nosy_count = 2.0
nosy_names = ['mark.dickinson', 'xxm']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = '24800'
type = 'behavior'
url = 'https://bugs.python.org/issue43507'
versions = ['Python 3.9']

[xxm]

The following code 1 calls function 'compile' and 'exec' and execute a statement "s=1". Then we print the value of 's'. This code can perform well on Python 3.9.2 and output the expected result. However, we pack the whole code into a function (code 2). The execution fails.

code 1:
===================

mstr = "s=1"
exec(compile(mstr,'','exec'))
print(s)

===================
output: 1

code2:
===================

def foo():
     mstr = "s=1"
     exec(compile(mstr,'','exec'))
     print(s)
foo()

===================

output: 
Traceback (most recent call last):
    File "/home/xxm/Desktop/apifuzz/doc/genDoc.py", line 37, in <module>
            foo()
    File "/home/xxm/Desktop/apifuzz/doc/genDoc.py", line 35, in foo
            print(s)
NameError: name 's' is not defined

By the way, we print locals(). 's' exists in the local scope. It should not fail.

>print(locals()）
{'mstr': 's=1', 's': 1}

[mdickinson]

I think this is essentially a duplicate of bpo-24800. (Short version, the behaviour is by design, and documented, but there may be scope for clarifying or improving the documentation.)