Re: [protobuf] MutableExtension crash in Release only

['Feng Xiao' via Protocol Buffers]

On Tue, Mar 27, 2018 at 5:24 AM Vylsain  wrote:

> Hi,
>
> I'm trying to implement polymorphism with protobuf. I want to have several
> levels, each new level extending the previous one.
> I have a crash when calling MutableExtension.
>
> My .proto file looks like :
>
>
> *package aapb;*
>
> *message A*
> *{*
> * optional int32 fooA = 1;*
>
> * extensions 1000 to max;*
> *}*
>
> *message B*
> *{*
> * extend A*
> * {*
>
> *optional B b = 1000;*
>
> * }*
>
> * optional int32 fooB = 1;*
>
> * extensions 1000 to max;*
> *}*
>
> *message C*
> *{*
> * extend B*
>
> * {*
>
> *optional C c = 1000;*
>
> * }*
>
> * optional int32 fooC = 1;*
>
> * extensions 1000 to max;*
> *}*
>
>
>
> On the C++ side, I have the corresponding classes :
>
> *class A*
> *{*
> *virtual void WriteExtensions(aapb::A *pA){}*
> *}*
>
> *class B : public A*
> *{*
> *virtual void WriteExtensions(aapb::A *pA)*
> *{*
> *aapb::B* pB = pA->MutableExtension(aapb::B::b);*
> *pB->fooB = 1;*
> *WriteExtensions(pB);*
> *}*
>
> *virtual void WriteExtensions(aapb::B *pB){}*
> *}*
>
> *class C : public B*
> *{*
> *virtual void WriteExtensions(aapb::B *pB)*
> *{*
> *aapb::C* pC = pB->MutableExtension(aapb::C::c);
>//crash happens here*
> *pC->fooC = 2;*
> *}*
> *}*
>
> Then, in my program I just create shared_ptr and aapb::A objects and
> call C's WriteExtensions method with aapb::A reference as an argument.
> It works as expected in Debug and I retrieve the correct data when reading
> the file.
> But in Release, I have a segfault when writing the file, when it reaches
> the MutableExtension call of the C class.
> To be more precise, the segfault happens on the call of 
> *google::protobuf::internal::ExtensionSet::MutableMessage(int,
> unsigned char, google::protobuf::MessageLite const&,
> google::protobuf::FieldDescriptor const*) ()*
>
> I'm struggling to see where the problem is coming from and wanted to make
> sure the protobuf part is correct before I look for other causes.
> So you guys see anything wrong in the way I use this ?
>
I don't see a problem there, except that "pB->fooB = 1; " won't compile.
It's likely the problem is not in the code shown above.


>
> Thanks
>
>
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[protobuf] MutableExtension crash in Release only

[Vylsain]

Hi,
 
I'm trying to implement polymorphism with protobuf. I want to have several 
levels, each new level extending the previous one.
I have a crash when calling MutableExtension.

My .proto file looks like :


*package aapb;*

*message A*
*{*
* optional int32 fooA = 1;*

* extensions 1000 to max;*
*}*

*message B*
*{*
* extend A*
* {*

*optional B b = 1000;*

* }*

* optional int32 fooB = 1;*

* extensions 1000 to max;*
*}*

*message C*
*{*
* extend B*

* {*

*optional C c = 1000;*

* }*

* optional int32 fooC = 1;*

* extensions 1000 to max;*
*}*



On the C++ side, I have the corresponding classes :

*class A*
*{*
*virtual void WriteExtensions(aapb::A *pA){}*
*}*

*class B : public A*
*{*
*virtual void WriteExtensions(aapb::A *pA)*
*{*
*aapb::B* pB = pA->MutableExtension(aapb::B::b);*
*pB->fooB = 1;*
*WriteExtensions(pB);*
*}*

*virtual void WriteExtensions(aapb::B *pB){}*
*}*

*class C : public B*
*{*
*virtual void WriteExtensions(aapb::B *pB)*
*{*
*aapb::C* pC = pB->MutableExtension(aapb::C::c);
 //crash happens here*
*pC->fooC = 2;*
*}*
*}*

Then, in my program I just create shared_ptr and aapb::A objects and 
call C's WriteExtensions method with aapb::A reference as an argument.
It works as expected in Debug and I retrieve the correct data when reading 
the file.
But in Release, I have a segfault when writing the file, when it reaches 
the MutableExtension call of the C class.
To be more precise, the segfault happens on the call of 
*google::protobuf::internal::ExtensionSet::MutableMessage(int, 
unsigned char, google::protobuf::MessageLite const&, 
google::protobuf::FieldDescriptor const*) ()*

I'm struggling to see where the problem is coming from and wanted to make 
sure the protobuf part is correct before I look for other causes.
So you guys see anything wrong in the way I use this ?

Thanks


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