Re: Why we should avoid new submodules if possible

[Michael S. Tsirkin]

On Tue, Jun 28, 2022 at 12:21:39PM +0200, Thomas Huth wrote:
> On 28/06/2022 12.03, Michael S. Tsirkin wrote:
> [...]
> > For biosbits if we are going this route then I feel a submodule is much
> > better.  It records which version exactly each qemu version wants.
> 
> As far as I know, you can also specify the version when using pip, can't
> you? So that's not really an advantage here.
> 
> On the contrary, submodules have a couple of disadvantages that I really
> dislike:
> 
> - submodules do not get updated automatically when doing a "git checkout",
> we have to update them via a script instead. This causes e.g. trouble if you
> rsync your source tree to a machine that has no access to the internet and
> you forgot to update the submodule before the sync
> 
> - the content of submodules is not added to the tarballs that get created on
> the git forges automatically. There were lots of requests from users in the
> past that tried to download a tarball from github and then wondered why they
> couldn't compile QEMU.
> 
> - we include the submodule content in our release tarballs, so people get
> the impression that hte submodule content is part of the QEMU sources. This
> has two disadvantages:
>  * We already got bug reports for the code in the submodule,
>    where people did not understand that they should report that
>    rather to the original project instead (i.e. you ship it - you
>    own it)
>  * People get the impression that QEMU is a huge monster
>    application if they count the number of code lines, run
>    their code scanner tools on the tarball contents, etc.
>    Remember "nemu", for example, where one of the main complaints
>    was that QEMU has too many lines of code?
> 
> - If programs includes code via submodules, this gets a higher
>   burder for distro maintainers, since they have to patch each
>   and every package when there is a bug, instead of being able to
>   fix it in one central place.
> 
> So in my opinion we should avoid new submodules if there is an alternative.
> 
>  Thomas

So looking at the latest proposals downloading files from CI,
checksumming them etc etc. No auto checkout, not added automatically
either, right?

This seems to be the only difference:
- we include the submodule content in our release tarballs

How about we just fix that? Thomas would that address your
concern at least wrt tests?


-- 
MST