[gentoo-dev] [rfc] dev-libs/expat[unicode] and dev-libs/libbsd dependency

[gentoo-dev] [rfc] dev-libs/expat[unicode] and dev-libs/libbsd dependency

[Sebastian Pipping]

Hi!


The next release of dev-libs/expat is not far away and there are two
things that I would appreciate input with, before the next bump in Gentoo:


-DXML_UNICODE_WCHAR_T issues and Gentoo/Debian mismatch
=======================================================

With USE=unicode, on Gentoo two extra libraries are built:

 * libexpatu.so (with CPPFLAGS=-DXML_UNICODE)
 * libexpatw.so (with CPPFLAGS=-DXML_UNICODE_WCHAR_T)
           ^
However, -DXML_UNICODE_WCHAR_T has only ever worked with 2-byte wchar_t,
while 4-byte wchar_t seems mainstream on Linux (and GCC -fshort-wchar
would required libc to have the same, if you actually wanted to pass
those wchar_t strings to wprintf and friends).

So libexpatw.so in Gentoo is not functional at the moment.

To make things worse, Debian has libexpatw.so with
CPPFLAGS=-DXML_UNICODE, which corresponds to current libexpatu.so in
Gentoo, rather than libexpatw.so.


How do you evaluate these options:

 a) Keep libexpatu.so + change libexpatw.so to CPPFLAGS=-DXML_UNICODE

 b) Drop libexpatu.so + change libexpatw.so to CPPFLAGS=-DXML_UNICODE


Depend on dev-libs/libbsd
=========================

The next release is very likely to add (optional but helpful) support
for arc4random_buf that dev-libs/libbsd provides (especially on systems
with glibc prior to 2.25) [1].  I wonder if Expat's proximity to @system
has any strong implications on whether

 A) libbsd should be a default-off use dependency
      IUSE="libbsd"  RDEPEND="libbsd? ( dev-libs/libbsd )"

 B) libbsd could be a default-on use dependency
      IUSE="+libbsd"  RDEPEND="libbsd? ( dev-libs/libbsd )"

 C) libbsd could even go into DEPEND and RDEPEND directly, or
      RDEPEND="dev-libs/libbsd"

 D) libbsd should not become any kind of future dependency of
    dev-libs/expat.


Thanks for your time!

Best



Sebastian


[1] https://github.com/libexpat/libexpat/pull/30

Re: [gentoo-dev] [rfc] dev-libs/expat[unicode] and dev-libs/libbsd dependency

[Michał Górny]

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On śro, 2017-05-31 at 14:19 +0200, Sebastian Pipping wrote:
> Hi!
> 
> 
> The next release of dev-libs/expat is not far away and there are two
> things that I would appreciate input with, before the next bump in Gentoo:
> 
> 
> -DXML_UNICODE_WCHAR_T issues and Gentoo/Debian mismatch
> =======================================================
> 
> With USE=unicode, on Gentoo two extra libraries are built:
> 
>  * libexpatu.so (with CPPFLAGS=-DXML_UNICODE)
>  * libexpatw.so (with CPPFLAGS=-DXML_UNICODE_WCHAR_T)
>            ^
> However, -DXML_UNICODE_WCHAR_T has only ever worked with 2-byte wchar_t,
> while 4-byte wchar_t seems mainstream on Linux (and GCC -fshort-wchar
> would required libc to have the same, if you actually wanted to pass
> those wchar_t strings to wprintf and friends).
> 
> So libexpatw.so in Gentoo is not functional at the moment.
> 
> To make things worse, Debian has libexpatw.so with
> CPPFLAGS=-DXML_UNICODE, which corresponds to current libexpatu.so in
> Gentoo, rather than libexpatw.so.
> 
> 
> How do you evaluate these options:
> 
>  a) Keep libexpatu.so + change libexpatw.so to CPPFLAGS=-DXML_UNICODE
> 
>  b) Drop libexpatu.so + change libexpatw.so to CPPFLAGS=-DXML_UNICODE

Does any other distribution use libexpatu.so? If not, then there's
probably no point in keeping it.

> 
> 
> Depend on dev-libs/libbsd
> =========================
> 
> The next release is very likely to add (optional but helpful) support
> for arc4random_buf that dev-libs/libbsd provides (especially on systems
> with glibc prior to 2.25) [1].  I wonder if Expat's proximity to @system
> has any strong implications on whether
> 
>  A) libbsd should be a default-off use dependency
>       IUSE="libbsd"  RDEPEND="libbsd? ( dev-libs/libbsd )"
> 
>  B) libbsd could be a default-on use dependency
>       IUSE="+libbsd"  RDEPEND="libbsd? ( dev-libs/libbsd )"

I'd dare say the feature is 'arc4random', then that should be the name
of the flag.

>  C) libbsd could even go into DEPEND and RDEPEND directly, or
>       RDEPEND="dev-libs/libbsd"
> 
>  D) libbsd should not become any kind of future dependency of
>     dev-libs/expat.
> 

-- 
Best regards,
Michał Górny

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Re: [gentoo-dev] [rfc] dev-libs/expat[unicode] and dev-libs/libbsd dependency

[Sebastian Pipping]

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Hi,


On 31.05.2017 21:16, Michał Górny wrote:
>> How do you evaluate these options:
>>
>>  a) Keep libexpatu.so + change libexpatw.so to CPPFLAGS=-DXML_UNICODE
>>
>>  b) Drop libexpatu.so + change libexpatw.so to CPPFLAGS=-DXML_UNICODE
> 
> Does any other distribution use libexpatu.so? If not, then there's
> probably no point in keeping it.

I found none but CoreOS, which is derived from Gentoo (..).


>>  A) libbsd should be a default-off use dependency
>>       IUSE="libbsd"  RDEPEND="libbsd? ( dev-libs/libbsd )"
>>
>>  B) libbsd could be a default-on use dependency
>>       IUSE="+libbsd"  RDEPEND="libbsd? ( dev-libs/libbsd )"
> 
> I'd dare say the feature is 'arc4random', then that should be the name
> of the flag.

Good point.

Best



Sebastian


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Re: [gentoo-dev] [rfc] dev-libs/expat[unicode] and dev-libs/libbsd dependency

[Sebastian Pipping]

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Hi!


Just quick note for the record: 2.2.0-r2 has these changes now, no need
to have that wait for the next release:

https://github.com/gentoo/gentoo/commit/715a2315ee2b841e38843e61b43ee058b5678cab

Best



Sebastian


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