JezK
Edit File: fix_raise.py
"""Fixer for 'raise E, V, T' raise -> raise raise E -> raise E raise E, V -> raise E(V) raise E, V, T -> raise E(V).with_traceback(T) raise E, None, T -> raise E.with_traceback(T) raise (((E, E'), E''), E'''), V -> raise E(V) raise "foo", V, T -> warns about string exceptions CAVEATS: 1) "raise E, V" will be incorrectly translated if V is an exception instance. The correct Python 3 idiom is raise E from V but since we can't detect instance-hood by syntax alone and since any client code would have to be changed as well, we don't automate this. """ # Author: Collin Winter # Local imports from .. import pytree from ..pgen2 import token from .. import fixer_base from ..fixer_util import Name, Call, Attr, ArgList, is_tuple class FixRaise(fixer_base.BaseFix): BM_compatible = True PATTERN = """ raise_stmt< 'raise' exc=any [',' val=any [',' tb=any]] > """ def transform(self, node, results): syms = self.syms exc = results["exc"].clone() if exc.type == token.STRING: msg = "Python 3 does not support string exceptions" self.cannot_convert(node, msg) return # Python 2 supports # raise ((((E1, E2), E3), E4), E5), V # as a synonym for # raise E1, V # Since Python 3 will not support this, we recurse down any tuple # literals, always taking the first element. if is_tuple(exc): while is_tuple(exc): # exc.children[1:-1] is the unparenthesized tuple # exc.children[1].children[0] is the first element of the tuple exc = exc.children[1].children[0].clone() exc.prefix = u" " if "val" not in results: # One-argument raise new = pytree.Node(syms.raise_stmt, [Name(u"raise"), exc]) new.prefix = node.prefix return new val = results["val"].clone() if is_tuple(val): args = [c.clone() for c in val.children[1:-1]] else: val.prefix = u"" args = [val] if "tb" in results: tb = results["tb"].clone() tb.prefix = u"" e = exc # If there's a traceback and None is passed as the value, then don't # add a call, since the user probably just wants to add a # traceback. See issue #9661. if val.type != token.NAME or val.value != u"None": e = Call(exc, args) with_tb = Attr(e, Name(u'with_traceback')) + [ArgList([tb])] new = pytree.Node(syms.simple_stmt, [Name(u"raise")] + with_tb) new.prefix = node.prefix return new else: return pytree.Node(syms.raise_stmt, [Name(u"raise"), Call(exc, args)], prefix=node.prefix)