[Debian-science-sagemath] Sage 7.6 testing migration blocked by giac

[Tobias Hansen]

On 06/20/2017 11:55 AM, Ximin Luo wrote:
> Tobias Hansen:
>> On 06/20/2017 10:56 AM, Ximin Luo wrote:
>>> Tobias Hansen:
>>>> Hi,
>>>>
>>>> dependencies of sage 7.6 have now started to migrate to testing, but
>>>> sage 7.6 can't migrate because giac is blocked due to missing builds on
>>>> armel, armhf and mipsel due to #855078. That means until giac can
>>>> migrate, we have a broken sage 7.4 in testing.
>>>>
>>>> Ximin, did you see that there are new comments on #855078? Maybe they help?
>>>>
>>> Hi, I took a look and the build failures look unrelated to #855078. This bug is a segfault on non-x86 64-bit arches, the build failures we're seeing seem like build rule issues, and fixable. I'll take a look later today.
>>>
>>>> Also, any ideas how we can prevent such incomplete migrations that break
>>>> the old sage version in the future?
>>>>
>>> I actually was not expecting giac to built on armhf/mipsel and was surprised that it did before. But if it's too hard to fix, the easy way to force the migration (for this and future packages) is to upload a version that only declares Architecture: amd64 i386.
>>>
>> I meant more generally. This can happen every time we upload a new bunch
>> of packages for a new Sage version to unstable. If we don't get
>> everything to migrate to testing together it can easily break Sage in
>> testing.
>>
> In those situations, if we control the package, we could do similar to what we did in brial (0.8.5-4) and add a Breaks: sagemath (<= XXX) to prevent testing migration, until the newer version of sagemath and all its dependencies are ready to go in.
>
> X

If that works, we should start doing this routinely. But are you sure it
really works? brial 0.8.5-4 and sagemath 7.4-6 migrated to testing
together, but that was because this sagemath version was uploaded after
brial and depended on the brial version.

I seem to remember that I had doubts that this Breaks would prevent
brial from migrating without sagemath. Maybe it was because the Breaks
was not mentioned in the testing migrations box on
https://tracker.debian.org/pkg/brial.

Best,
Tobias