Re: [Buildroot] [PATCH] package/mono: allow to select which folders to install to target

[Giulio Benetti <giulio.benetti@benettiengineering.com>]

Hi Yann,

On 31/10/22 13:54, Yann E. MORIN wrote:
> Giulio, Thomas, All,
> 
> On 2022-10-31 13:25 +0100, Thomas Petazzoni via buildroot spake thusly:
>> On Wed, 19 Oct 2022 01:46:17 +0200
>> Giulio Benetti <giulio.benetti@benettiengineering.com> wrote:
>>> At the moment all APIs folders are copied to target increasing the size of
>>> rootfs of ~190MB. Allow to select which API folders we want to copy to
>>> target to shrink rootfs down.
>>>
>>> Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
>> Practically speaking, could you describe which folders are needed in a
>> typical scenario you've had?
> 
> Yes, can you provide a rationale for when only a subset of APIs is
> needed?

I've answered on previous e-mail. I've realized only now that I could
answer to your e-mail for both.

>> Here, I have these ones:
>>
>> drwxr-xr-x   2 thomas thomas  4096 oct.  25 22:58 2.0-api
>> drwxr-xr-x   2 thomas thomas  4096 oct.  25 22:58 3.5-api
>> drwxr-xr-x   2 thomas thomas  4096 oct.  25 22:56 4.0
>> drwxr-xr-x   2 thomas thomas 12288 oct.  25 22:58 4.0-api
>> drwxr-xr-x   4 thomas thomas 16384 oct.  25 22:58 4.5
>> drwxr-xr-x   3 thomas thomas 12288 oct.  25 22:58 4.5.1-api
>> drwxr-xr-x   3 thomas thomas 12288 oct.  25 22:58 4.5.2-api
>> drwxr-xr-x   3 thomas thomas 12288 oct.  25 22:58 4.5-api
>> drwxr-xr-x   3 thomas thomas 12288 oct.  25 22:58 4.6.1-api
>> drwxr-xr-x   3 thomas thomas 12288 oct.  25 22:58 4.6.2-api
>> drwxr-xr-x   3 thomas thomas 12288 oct.  25 22:58 4.6-api
>> drwxr-xr-x   3 thomas thomas 12288 oct.  25 22:58 4.7.1-api
>> drwxr-xr-x   3 thomas thomas 12288 oct.  25 22:58 4.7.2-api
>> drwxr-xr-x   3 thomas thomas 12288 oct.  25 22:58 4.7-api
>> drwxr-xr-x   3 thomas thomas 12288 oct.  25 22:58 4.8-api
>> drwxr-xr-x 145 thomas thomas 12288 oct.  25 22:56 gac
>> drwxr-xr-x   2 thomas thomas  4096 oct.  25 22:56 lldb
>> drwxr-xr-x   3 thomas thomas  4096 oct.  25 22:56 mono-configuration-crypto
>> drwxr-xr-x   2 thomas thomas  4096 oct.  25 22:56 monodoc
>> drwxr-xr-x   3 thomas thomas  4096 oct.  25 22:56 msbuild
>> drwxr-xr-x   6 thomas thomas  4096 oct.  25 22:56 xbuild
>> drwxr-xr-x   4 thomas thomas  4096 oct.  25 22:56 xbuild-frameworks
> 
> It looks like we have three sets of directories here;
>    - version-based dirs: from 2.0-api up to 4.8-api
>    - gac/: big number of subdirs in there...
>    - the rest
> 
> Your change trat them all on the same level, but are they all really
> superfluous? Is there a set that absolutely needs to be there, or can we
> really do with just one (or even none, see below)?
> 
> Note: can we unconditionally get rid of monodoc/? Of msbuild/? Of lldb/?

To tell the truth I'm not expert in this. I know that my customer's
application only needed the files in those folders.
So I can't find at the moment something that clarifies this, that's why
I've given a very open solution. Of course this can give problems in
runtime. But the mono application should fail immediately if someone
skip some folder.

>>> +config BR2_PACKAGE_MONO_SPECIFY_FOLDERS_TO_INSTALL
>>> +	bool "Specify folders to install to target"
>>> +	help
>>> +	  Allow to specify which Mono folder to install to target
>>
>> I don't really have a very good suggestion, but I don't like the name
>> of the option. We rarely have option names that are "sentences", i.e
>> "specify folders to install" is a sentence.
>>
>> Should we instead have a single string option
>> BR2_PACKAGE_MONO_INSTALL_LIB_DIRS, which is empty by default. When
>> empty, it means all folders are installed. Otherwise, only the
>> specified folders are installed.
> 
> Agreed. I expect that having no API level installed would yield a
> non-working system, so:
> 
>      config BR2_PACKAGE_MONO_API_VERSIONS
>          string "API versions to install"
>          help
>            Keep empty to install all.

Ok, I go with that then!

>> The other obvious question is whether this shouldn't simply be left as
>> something to do in a post-build script. Even though I admit that
>> reducing 190 MB down to something reasonable can be seen as something
>> that is almost mandatory.
>>
>> Or alternatively, do we have a better way, where we could automate this
>> selection of which folders are needed?
> 
> I would prefer we avoid carrying the list of versionned APIs (and the
> rest, see above).

Yes I agree, otherwise the list would be pretty long.

Best regards
-- 
Giulio Benetti
CEO/CTO@Benetti Engineering sas
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