PyLint reports "no assignment is done" but variable is changed in the scope of the procedure

[motib79]

Bug description

I got the message:
Using global for 'ticker' but no assignment is done

for the code:
---
def remove_ticker_from_list(stock_index):
    global ticker
    ticker[stock_index]="NULL_STOCK"

Configuration

No response

Command used

VSCode

Pylint output

mentioned in descr

Expected behavior

do not report this error

Pylint version

Python 3.10.11 (tags/v3.10.11:7d4cc5a, Apr  5 2023, 00:38:17) [MSC v.1929 64 bit (AMD64)] on win32

OS / Environment

Win10

Additional dependencies

No response

[mbyrnepr2]

Thanks @motib79.

Using global for 'ticker' but no assignment is done - in other words, the global ticker line is not necessary and can be removed.

Here is where global would be necessary:

ticker = {1: 2}

def remove_ticker_from_list(stock_index):
    global ticker
    ticker = "NULL_STOCK"

remove_ticker_from_list('x')
print(ticker)

NULL_STOCK

Perhaps the documentation could be updated to make it more clear?

[motib79]

Thanks for the comments. Ticker is a list. And modified in the scope of the procedure. Therefore I believe global assignment is required as like in case of any other variable changes. Looks like PyLint does not recognize list change as a change that require global assignment .

On Thu, 28 Mar 2024, 15:54 Mark Byrne, @.***> wrote:

Thanks @motib79 https://github.com/motib79.

Using global for 'ticker' but no assignment is done - in other words, the global ticker line is not necessary and can be removed.

Here is where global would be necessary:

ticker = {1: 2} def remove_ticker_from_list(stock_index): global ticker ticker = "NULL_STOCK" remove_ticker_from_list('x')print(ticker) NULL_STOCK

Perhaps the documentation https://pylint.readthedocs.io/en/stable/user_guide/messages/warning/global-variable-not-assigned.html could be updated to make it more clear?

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[mbyrnepr2]

@motib79 I think that is the same situation for list or dict. I think this is your example (expanded a bit to show the list definition outside the function). Python is happy with this and global isn't needed here because you are not re-assigning ticker but rather some element contained within ticker:

(venv312) markbyrne@Marks-Air-2 programming % cat example.py 
ticker = [1, 2, 3]


def remove_ticker_from_list(stock_index):
    ticker[stock_index]="NULL_STOCK"

 
remove_ticker_from_list(0)
print(ticker)
(venv312) markbyrne@Marks-Air-2 programming % python example.py
['NULL_STOCK', 2, 3]

[motib79]

Ok, thanks for the clarification.

On Fri, 29 Mar 2024, 15:36 Mark Byrne, @.***> wrote:

@motib79 https://github.com/motib79 I think that is the same situation for list or dict. I think this is your example (expanded a bit to show the list definition outside the function). Python is happy with this and global isn't needed here because you are not re-assigning ticker but rather some element contained within ticker. Global would be needed if ticker were a string, for example, because the assignment inside the function wouldn't affect ticker which is defined outside the function:

(venv312) @.*** programming % cat example.py ticker = [1, 2, 3]

def remove_ticker_from_list(stock_index): ticker[stock_index]="NULL_STOCK"

remove_ticker_from_list(0)print(ticker) (venv312) @.*** programming % python example.py ['NULL_STOCK', 2, 3]

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