Question

my_var = 3
assert('my_var' in locals())

import a_module
assert('a_module' in locals())

from sys import *
assert('stdin' in locals())

I also think you can inject with calls to locals() and globals()?

Anyway, I love python because it’s so explicit with imports. If a name is used, you can usually trace back to exactly where that name was defined. But, I’ve recently been running into modules wherein I want to find where the name qux is defined. The module itself contains no from something import *, no locals or globals, but when I CTRL+F for that name I find it only on the RHS of expressions, nowhere defined!

So my question is this: what are all the mechanisms by which a name can enter the local namespace? Can normal imports inject into my local namespace?

Answer 1

Some other module may inject the name in this module:

#x.py
import y
y.lol = 1
y.func()

And this module does not define it:

#y.py
def func():
    print(lol)

Another crazy way someone may inject code in another module would be:

#a.py
import sys
sys._getframe(1).f_globals['lol'] = 1

So, a.py will inject the name lol in whoever import it

#b.py
import a
print(lol)