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Date: Tue, 10 Feb 2015 08:50:54 +0400
Message-ID: <CA+9eiLvNxdmwT+k0enLw5WLAPQ8efvZ_aG=QgWBhP+zTutnnkg@mail.gmail.com>
To: Stanislav Malyshev <smalyshev@gmail.com>
Cc: PHP Internals <internals@lists.php.net>, Yasuo Ohgaki <yohgaki@ohgaki.net>
Content-Type: multipart/alternative; boundary=089e0115fd02bf2e20050eb4a180
Subject: Re: [PHP-DEV] Re: Design by Contract
From: dmitry@zend.com (Dmitry Stogov)

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On Feb 10, 2015 3:25 AM, "Stanislav Malyshev" <smalyshev@gmail.com> wrote:
>
> Hi!
>
> > constraints. Type check is one of them. There are many people argue
"This
> > language is secure and robust because it has _static_ types".
>
> These people are wrong. Languages can't really be secure or robust, only
> code implemented in these languages can, and we have witnessed many
> examples of vulnerable code written in pretty much any widely used
> language. Having strict typing may protect against some very basic
> errors, but in well-designed and well-tested software such errors would
> be rare, and in badly designed software type strictness would not save
you.
>
> > Here comes DbC, once we have contracts for pre/post conditions. We are
> > safe from calling functions with invalid parameters during development,
yet
> > we have optimum performance for production since there is zero contract
> > checks
> > with production mode including opcode.
>
> That assumes perfect test coverage in development, both code-wise and,
> more importantly, data-wise. Which is impossible. While having assert
> primitives that can be turned on and off looks like a useful concept to
> me, I don't think it is some kind of magic solution that will change
> everything.

DbC is just an approach that may help to write safer programs. Of course,
it's just a tool and can't gurantee anything. It's also possible to write
safe code in assembler, but it's more difficult.

Thanks. Dmitry.

> --
> Stas Malyshev
> smalyshev@gmail.com
>
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