Re: preparing for GCC 5, especially libstdc++6
On 06/26/2015 03:01 AM, Emilio Pozuelo Monfort wrote:
> On 25/06/15 17:44, Matthias Klose wrote:
>> On 06/25/2015 01:20 PM, Matthias Klose wrote:
>>> On 06/25/2015 11:23 AM, Emilio Pozuelo Monfort wrote:
>>>> - You suggest that some libraries may need to be renamed due to the ABI breaks.
>>>> Do you have a list of affected libraries?
>>>
>>> No. Getting this list is a bit difficult. Candidates for these packages are the
>>> GCC 5 build failures due to mismatched symbols files. However there may be more
>>> packages which successfully build, but have additional symbols (this may be an
>>> empty set, because usually some symbol names should be just replaced by new ones).
>>
>> If symbol versioning is used in a library, you probably won't see this at all,
>> until the package is built using GCC 5. I'll ask for another test rebuild with a
>> diverted dpkg-gensymbols to look at the generated symbols files.
>
> Thanks Matthias. I'd be very interested in knowing more about what breaks.
We have 361 C++ libraries which define at least one of these new symbols [1].
Note this list only includes the packages which succeed to build with GCC 5.
Another 70 packages might need the same action (the issues at [2] with severity
important, which fail during the dpkg-gensymbols call).
So my proposal would be to file bug reports for each of these packages, asking
the maintainers for what to do with this library. Actions could be:
- do nothing, if none of these symbols are part of the library ABI. That
would be a rebuild of the library and its reverse dependencies.
- add breaks to all reverse dependencies on this library, and rebuild
the library and the reverse dependencies.
- rename the library package and rebuild all reverse dependencies.
The default action should be the most conservative action (the renaming of the
library package).
These bug reports could be used as transition bug reports as well, once GCC 5 is
the default. Then these could be reassigned to release.debian.org once the
transitions start.
Matthias
[1] https://people.debian.org/~doko/logs/gcc5-20150701/
[2]
https://bugs.debian.org/cgi-bin/pkgreport.cgi?tag=ftbfs-gcc-5;users=debian-gcc@lists.debian.org
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