exec() ignores scope.

[Keepun]

BPO	43448
Nosy	@mdickinson, @eryksun, @Keepun
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.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-03-10.11:09:55.188>
created_at = <Date 2021-03-09.15:42:58.560>
labels = ['interpreter-core', '3.8', 'type-bug', '3.7']
title = 'exec() ignores scope.'
updated_at = <Date 2021-03-10.11:09:55.187>
user = 'https://github.com/Keepun'

bugs.python.org fields:

activity = <Date 2021-03-10.11:09:55.187>
actor = 'mark.dickinson'
assignee = 'none'
closed = True
closed_date = <Date 2021-03-10.11:09:55.188>
closer = 'mark.dickinson'
components = ['Interpreter Core']
creation = <Date 2021-03-09.15:42:58.560>
creator = 'Keepun'
dependencies = []
files = []
hgrepos = []
issue_num = 43448
keywords = []
message_count = 3.0
messages = ['388366', '388370', '388425']
nosy_count = 3.0
nosy_names = ['mark.dickinson', 'eryksun', 'Keepun']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = '24800'
type = 'behavior'
url = 'https://bugs.python.org/issue43448'
versions = ['Python 3.7', 'Python 3.8']

[Keepun]

exec() ignores scope.

Code:
--------------------------

class ExecTest:
    def public(self):
        h=None
        exec("h='It is public'")
        print(h)
        self._private()
    def _private(self):
        h=None
        exec("h='It is private'", globals(), locals())
        print(h)

h = None
exec("h='It is global'")
print(h)

e=ExecTest()
e.public()

Result
--------------------------
It is global
None
None

--------------------------
Python 3.7.10 (default, Feb 26 2021, 13:06:18) [MSC v.1916 64 bit (AMD64)]
and
Python 3.8.5 (default, Jan 27 2021, 15:41:15) [GCC 9.3.0]

[eryksun]

exec(obj, globals(), locals()) is the same as exec(obj). Also, locals in a function scope are optimized, so the locals() dict is a snapshot. Modifying the snapshot dict doesn't modify the optimized local variables. At most I think this issue is a duplicate of bpo-24800, to clarify the implicit local scope and behavior.

[mdickinson]

At most I think this issue is a duplicate of bpo-24800

Agreed; closing here.