Re: [PATCH 2/7] tests/docker: Simplify debian-all-test-cross

[Philippe Mathieu-Daudé]

On 11/2/21 13:24, Alex Bennée wrote:
> Alex Bennée <alex.bennee@linaro.org> writes:
>> Philippe Mathieu-Daudé <f4bug@amsat.org> writes:
>>> On 10/18/21 12:54, Alex Bennée wrote:
>>>> Richard Henderson <richard.henderson@linaro.org> writes:
>>>>
>>>>> The base debian10 image contains enough to build qemu;
>>>>> we do not need to repeat that within the new image.
>>>>>
>>>>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>>>>> ---
>>>>>  tests/docker/dockerfiles/debian-all-test-cross.docker | 5 -----
>>>>>  1 file changed, 5 deletions(-)
>>>>>
>>>>> diff --git a/tests/docker/dockerfiles/debian-all-test-cross.docker 
>>>>> b/tests/docker/dockerfiles/debian-all-test-cross.docker
>>>>> index dedcea58b4..b185b7c15a 100644
>>>>> --- a/tests/docker/dockerfiles/debian-all-test-cross.docker
>>>>> +++ b/tests/docker/dockerfiles/debian-all-test-cross.docker
>>>>> @@ -8,11 +8,6 @@
>>>>>  #
>>>>>  FROM qemu/debian10
>>>>>  
>>>>> -# What we need to build QEMU itself
>>>>> -RUN apt update && \
>>>>> -    DEBIAN_FRONTEND=noninteractive eatmydata \
>>>>> -    apt build-dep -yy qemu
>>>>> -
>>>>>  # Add the foreign architecture we want and install dependencies
>>>>>  RUN DEBIAN_FRONTEND=noninteractive eatmydata \
>>>>>          apt install -y --no-install-recommends \
>>>>
>>>> Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
>>>
>>> IIUC if we keep --arch-only in the previous step (previous patch),
>>> this step is required here.
>>
>> What for? The --arch-only prevents the attempt to install cross
>> compilers that don't exist on a given host but we install all the cross
>> compilers we need for tests explicitly.
> 
> Well patches 1 & 2 have been a cause of hair tearing the last two days. If
> we replace the previous:
> 
>  $(apt-get -s build-dep --arch-only qemu | egrep ^Inst | fgrep '[all]' | cut 
> -d\  -f2)
> 
> which only installs (all) packages with:
> 
>   apt build-dep -yy --arch-only qemu
> 
> it breaks all the cross compiler images that are based on on debian10
> because suddenly their:
> 
>   apt build-dep -yy -a $ARCH --arch-only qemu
> 
> will fail to build. However this is somewhat hidden by the fact that
> most people pushing to gitlab would have that effect masked as the
> images will be based on the older ones in the registry.
> 
> Of course I ran into the opposite problem trying to test things as we
> aggressively used the upstream registry. As a result of the dropped the
> build-dep in the all-cross but without being based on the new image we
> end up without enough deps to build stuff.
> 
> In short I need to drop the first two patches.

I remember I had to do it this ugly way to simplify the
rest, and later I came back to it because Peter said it
was confusing, but I couldn't find a easier way to remove
this command.

Today I think we shouldn't bother to include intermediate
Dockerfiles. I'd simply use one plain file and let the
Docker daemon worry about caching/reusing.

But the whole machinery needs some thought since we want
to be able to use non-x86_64 hosts; and on the CI side
we want pulled images to be stable.