While committing issue #24129, I noticed the following in the execution model documentation: ================== If a variable is referenced in an enclosing scope, it is illegal to delete the name. An error will be reported at compile time. ================== I'm not sure what that means, as both of the following compiled fine for me under 3.4.2: >>> def f(): ... x = 1 ... def g(): ... nonlocal x ... del x ... >>> def f(): ... x = 1 ... del x ... def g(): ... print(x) ...
Note that I haven't attempted to resolve this myself, as I'm not sure if we should just delete the paragraph, or if we accidentally dropped a compile time error check that didn't have any tests somewhere along the line. Probably a good one to raise on python-dev...
I wonder if it is a left-over from the behaviour prior to 3.2? In 3.1, I get this syntax error: py> def outer(): ... spam = 1 ... def inner(): ... nonlocal spam ... del spam ... inner() ... SyntaxError: can not delete variable 'spam' referenced in nested scope See also the "Changed in 3.2" comment here: https://docs.python.org/3/reference/simple_stmts.html#the-del-statement
It looks like it is safe to just remove this line from docs. This code >>> x = 1 >>> def f(): ... global x ... del x ... >>> f() >>> x Works as expected, i.e. raises NameError. (The same happens for nonlocal but with UnboundLocalError.)
