Documentation
This is somewhat related to #116580. There are two references to NULL in the description of f-strings that don't have a clear meaning.
format_spec ::= (literal_char | NULL | replacement_field)*
literal_char ::= <any code point except "{", "}" or NULL>
In both cases (but especially literal_char), it could refer to U+0000, but I'm unaware that a null character is allowed anywhere in Python source. At least, my attempt to inject one failed:
>>> print(ast.dump(ast.parse("f'{x:"'\x00'"}'"), indent=2))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/ast.py", line 52, in parse
return compile(source, filename, mode, flags,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
SyntaxError: source code string cannot contain null bytesFor format_spec, it could refer to an empty specification (f'{x:}'), but (literal_char | replacement_field)* would cover that just as well.
Linked PRs
Documentation
This is somewhat related to #116580. There are two references to NULL in the description of f-strings that don't have a clear meaning.
In both cases (but especially
literal_char), it could refer to U+0000, but I'm unaware that a null character is allowed anywhere in Python source. At least, my attempt to inject one failed:>>> print(ast.dump(ast.parse("f'{x:"'\x00'"}'"), indent=2)) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/Library/Frameworks/Python.framework/Versions/3.12/lib/python3.12/ast.py", line 52, in parse return compile(source, filename, mode, flags, ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ SyntaxError: source code string cannot contain null bytesFor
format_spec, it could refer to an empty specification (f'{x:}'), but(literal_char | replacement_field)*would cover that just as well.Linked PRs