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digitalmars.D - Structs on private section.

reply Alexey Veselovsky <alexey.veselovsky gmail.com> writes:
Hi!

It seems like structs in private section (module or class) remains public:

class A {
private:
	struct B {int b;}
}

void foo() {A.B b; b.b=10;}

this code compiles ok.

WTF?
Nov 27 2011
parent reply =?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:
On 11/27/2011 03:57 PM, Alexey Veselovsky wrote:

 Hi!

 It seems like structs in private section (module or class) remains public:

 class A {
 private:
 	struct B {int b;}
 }

 void foo() {A.B b; b.b=10;}

 this code compiles ok.

 WTF?


D's private is different than some other languages (e.g. C++). 'private' 
provides access to the entire module.

public: no access limitation

private: access by the module

package: access by the modules of the package

protected: access by the inheriting classes

Ali
Nov 27 2011
parent reply Alexey Veselovsky <alexey.veselovsky gmail.com> writes:
=20
=20
=20
=20
=20


 D's private is different than some other languages (e.g. C++). 'private' p=


rovides access to the entire module.

=20
 public: no access limitation
=20
 private: access by the module
=20
 package: access by the modules of the package
=20
 protected: access by the inheriting classes


But it works even if class Foo declarated in dufferent module.

Also this code works:

module a;

private { struct S {int a;}}

--------

module b:
import a:

void f() {S s; s.a=3D42;}=
Nov 27 2011
parent reply deadalnix <deadalnix gmail.com> writes:
Le 28/11/2011 03:29, Alexey Veselovsky a écrit :


 D's private is different than some other languages (e.g. C++). 'private'
provides access to the entire module.

 public: no access limitation

 private: access by the module

 package: access by the modules of the package

 protected: access by the inheriting classes


 But it works even if class Foo declarated in dufferent module.

 Also this code works:

 module a;

 private { struct S {int a;}}

 --------

 module b:
 import a:

 void f() {S s; s.a=42;}


So you now have discovered a bug.



 Nov 27 2011



  parent  Peter Alexander <peter.alexander.au gmail.com>  writes:


On 28/11/11 1:56 AM, deadalnix wrote:

 Le 28/11/2011 03:29, Alexey Veselovsky a écrit :


 D's private is different than some other languages (e.g. C++).
 'private' provides access to the entire module.

 public: no access limitation

 private: access by the module

 package: access by the modules of the package

 protected: access by the inheriting classes


 But it works even if class Foo declarated in dufferent module.

 Also this code works:

 module a;

 private { struct S {int a;}}

 --------

 module b:
 import a:

 void f() {S s; s.a=42;}


 So you now have discovered a bug.


A bug that has been known about for quite some time. I also created a 
pull request for a fix quite some time ago (June), but hasn't been 
pushed yet.

https://github.com/D-Programming-Language/dmd/pull/163
+
https://github.com/D-Programming-Language/druntime/pull/32

Unfortunately, the druntime changes are required due to issue 314. For 
example, with the private type fix, the following code would not compile:

---------------
module A;
struct Foo {}; // public
---------------
module B;
import A : Foo; // private selective import
---------------
module C;
import B;
import A;
Foo f; // error: B.Foo is private
---------------

Due to bug 314, the private import in module B causes Foo to become a 
private symbol of module B (rather than just importing it). When module 
C tries to use Foo, it first looks in module B, finding the private Foo 
and complains of access violation. It doesn't even look at the Foo in 
module A because access checks are done before overload resolution.

It's quite ugly that access checks are not considered in overload 
resolution because it means I can break user code by adding private 
symbols to my library. It won't be a silent break, but it will break 
nonetheless.



 Nov 28 2011