[Python-ideas] Updated PEP 428 (pathlib)

Devin Jeanpierre jeanpierreda at gmail.com
Thu Mar 7 04:23:57 CET 2013


On Wed, Mar 6, 2013 at 6:25 PM, MRAB <python at mrabarnett.plus.com> wrote:
> You _can_ have catastrophic backtracking without capture groups. You've
> already seen an example in ".*a.*".
>
> It gets worse when you can have repeated repeats, for example "(?:.*)*".
>
> The difference with fnmatch is that you don't care _where_ various
> parts match (there are no capture groups), only _whether_ it matches,
> and then only whether or not _all_ of it matches.

We seem to be talking past each other. I already know all this. I am
asking you to justify your claim that if glob was based on regex,
instead of re, it would be free of DOS attacks.

Because of your confusion, I expect you didn't really mean to claim
that. I inferred it because when you were asked for an approach that
would solve DOS attacks against glob, you replied by saying that you
wrote a regex module that is more resistant to such things. I
apologize if I misunderstood.

-- Devin



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