[gentoo-dev] USE flag documentation

[gentoo-dev] USE flag documentation

[Mark Loeser]

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This is a very very rough draft/question about how we should move
forward with USE flag documentation and specification.  The entire idea
of a single USE flag having different meanings will need to be revisted
later.  I just want to get an idea of how we can document these
different meanings.  Please read my ideas here:

http://dev.gentoo.org/~halcy0n/gleps/glep-0054.html

Let me know if you like any of those ideas, or if they all suck (and if
they do, you better tell me why).  I'm not sure which is the best way
forward, which is why I want everyone to contribute towards the best
solution moving forward.  I really don't want to be stuck with something
that is going to end up being a pain a year down the road.

Thanks,

-- 
Mark Loeser
email         -   halcy0n AT gentoo DOT org
email         -   mark AT halcy0n DOT com
web           -   http://www.halcy0n.com

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Re: [gentoo-dev] USE flag documentation

[Alec Warner]

On 12/30/07, Mark Loeser <halcy0n@gentoo.org> wrote:
> This is a very very rough draft/question about how we should move
> forward with USE flag documentation and specification.  The entire idea
> of a single USE flag having different meanings will need to be revisted
> later.  I just want to get an idea of how we can document these
> different meanings.  Please read my ideas here:
>
> http://dev.gentoo.org/~halcy0n/gleps/glep-0054.html
>
> Let me know if you like any of those ideas, or if they all suck (and if
> they do, you better tell me why).  I'm not sure which is the best way
> forward, which is why I want everyone to contribute towards the best
> solution moving forward.  I really don't want to be stuck with something
> that is going to end up being a pain a year down the road.
>
> Thanks,
>

One of the GLEP's primary goals is to provide a global use flag
definition and over-ride
it with a local definition.  How does putting all flags in use.desc
and over-riding local flags in
use.local.desc not accomplish this?

How does the glep intend to handle USE_EXPAND?
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Re: [gentoo-dev] USE flag documentation

[Mark Loeser]

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Alec Warner <antarus@gentoo.org> said:
> One of the GLEP's primary goals is to provide a global use flag
> definition and over-ride
> it with a local definition.  How does putting all flags in use.desc
> and over-riding local flags in
> use.local.desc not accomplish this?

It does, and maybe that's what we should use instead?  The reason for
the email is to figure out if what we have now is good enough, or if we
should switch to something else.

> How does the glep intend to handle USE_EXPAND?

It doesn't say anything about them right now, but since you brought it
up...any ideas? :)

-- 
Mark Loeser
email         -   halcy0n AT gentoo DOT org
email         -   mark AT halcy0n DOT com
web           -   http://www.halcy0n.com

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Re: [gentoo-dev] USE flag documentation

[Doug Klima]

Mark Loeser wrote:
> Alec Warner <antarus@gentoo.org> said:
>   
>> One of the GLEP's primary goals is to provide a global use flag
>> definition and over-ride
>> it with a local definition.  How does putting all flags in use.desc
>> and over-riding local flags in
>> use.local.desc not accomplish this?
>>     
>
> It does, and maybe that's what we should use instead?  The reason for
> the email is to figure out if what we have now is good enough, or if we
> should switch to something else.
>
>   

You're the one forcing people to remove overriding USE flags from
use.local.desc when that's something that people have been doing for
ages. The current Portage tools support that method.
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Re: [gentoo-dev] USE flag documentation

[Mark Loeser]

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Doug Klima <cardoe@gentoo.org> said:
> You're the one forcing people to remove overriding USE flags from
> use.local.desc when that's something that people have been doing for
> ages. The current Portage tools support that method.

Because this behaviour is not documented anywhere, and if you check, the
only ones I've removed so far are ones that are word for word
duplicates.  I'm also not sure if using the existing use.desc and
use.local.desc is the best way to move forward.

I have these different suggestions to see which one people like the best
and to see how I can improve upon them.

Thanks,

-- 
Mark Loeser
email         -   halcy0n AT gentoo DOT org
email         -   mark AT halcy0n DOT com
web           -   http://www.halcy0n.com

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Re: [gentoo-dev] USE flag documentation

[Piotr Jaroszyński]

On Wednesday 02 of January 2008 16:58:33 Mark Loeser wrote:
> Doug Klima <cardoe@gentoo.org> said:
> > You're the one forcing people to remove overriding USE flags from
> > use.local.desc when that's something that people have been doing for
> > ages. The current Portage tools support that method.
>
> Because this behaviour is not documented anywhere

It is documented in the PMS draft and imho it makes perfect sense (at least 
with current solution):

"Flags must be listed once for each package to which they apply, or if a flag 
is listed in both use.desc and use.local.desc, it must be listed once for 
each package for which its meaning differs from that described in use.desc."

-- 
Best Regards,
Piotr Jaroszyński
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Re: [gentoo-dev] USE flag documentation

[Denis Dupeyron]

I like the overall idea. I will comment the first proposed alternative
as this is the one that makes the most sense in my opinion.

> Having one global use.xml where the default definitions are, and then using metadata.xml for each package to override the USE flag definition.

With 's/default definitions/global USE flag definitions/' and
's/override the USE flag definition/define the local USE flags/' I
would be even happier. Global USE flags should be defined in a central
place and never be overridden. Local flags should be defined locally
i.e. in the package subdirectory.

I'd even go as far as adding that metadata.xml could include some
clarifications/specifics/notes/warnings/whatever about a global USE
flag for a given package, but that should not be a redefinition of the
global USE flag. This would be appended by third party tools to
complement the definition of the global USE flag in the context of
that particular package.

> Problems with this approach include...
> * Easy to duplicate USE flags since we don't have a central repository for them.

I'm not following you here. We'd have a central use.xml, so what do
you mean ? And it's OK for local flags to be conflicting or duplicated
since they're local.

> Lots of small files to go and parse to get the full picture of the tree.

This can be cached.

Denis.
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Re: [gentoo-dev] USE flag documentation

[Doug Klima]

Marius Mauch wrote:
> On Sun, 30 Dec 2007 19:54:04 -0500
> Mark Loeser <halcy0n@gentoo.org> wrote:
> 
>> Let me know if you like any of those ideas, or if they all suck (and if
>> they do, you better tell me why).  I'm not sure which is the best way
>> forward, which is why I want everyone to contribute towards the best
>> solution moving forward.  I really don't want to be stuck with something
>> that is going to end up being a pain a year down the road.
> 
> What benefit does use.xml have over use.desc?
> 
> My opinion is that we should use use.desc for a complete list of use
> flags, including a generic description, allow a more verbose
> description in metadata.xml and get rid of the stupid separation of
> "local" and "global" flags. No need to change the format of use.desc
> though.

I completely agree with this. This allows each individual package to 
provide more insight to what a USE flag does.

> The only benefit use.local.desc gives us is a fast way to list packages
> using some flags, but that's unreliable at best. If needed such a list
> could be autogenerated.
> 
> Marius


-- 
Doug Klima <cardoe@gentoo.org>
http://dev.gentoo.org/~cardoe/
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Re: [gentoo-dev] USE flag documentation

[Mark Loeser]

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Doug Klima <cardoe@gentoo.org> said:
> Marius Mauch wrote:
>> What benefit does use.xml have over use.desc?
>> My opinion is that we should use use.desc for a complete list of use
>> flags, including a generic description, allow a more verbose
>> description in metadata.xml and get rid of the stupid separation of
>> "local" and "global" flags. No need to change the format of use.desc
>> though.
>
> I completely agree with this. This allows each individual package to 
> provide more insight to what a USE flag does.

This sounds sane to me as well.  As I said, I'm just throwing ideas out
there to see what sticks :)

>> The only benefit use.local.desc gives us is a fast way to list packages
>> using some flags, but that's unreliable at best. If needed such a list
>> could be autogenerated.

Completely agree.

-- 
Mark Loeser
email         -   halcy0n AT gentoo DOT org
email         -   mark AT halcy0n DOT com
web           -   http://www.halcy0n.com

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Re: [gentoo-dev] USE flag documentation

[Denis Dupeyron]

On Dec 31, 2007 3:30 PM, Marius Mauch <genone@gentoo.org> wrote:
> What benefit does use.xml have over use.desc?
[...]
> No need to change the format of use.desc

Anything that would enable us to document with more than a few words,
which is what we're practically limited to with the current format of
use.desc, would help. The currently available documentation on USE
flags is clearly insufficient, maybe not for you and me and other
devs, but for the majority of our users. Note that this is not the
same as optionally adding more specific documentation on a global flag
in the metadata.xml of a package.

> and get rid of the stupid separation of "local" and "global" flags

Good idea. How do you plan to cope with the (currently) local USE flag
conflicts though ?

Denis.
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Re: [gentoo-dev] USE flag documentation

[Marius Mauch]

On Mon, 31 Dec 2007 18:55:10 +0100
"Denis Dupeyron" <calchan@gentoo.org> wrote:

> On Dec 31, 2007 3:30 PM, Marius Mauch <genone@gentoo.org> wrote:
> > What benefit does use.xml have over use.desc?
> [...]
> > No need to change the format of use.desc
> 
> Anything that would enable us to document with more than a few words,
> which is what we're practically limited to with the current format of
> use.desc, would help. The currently available documentation on USE
> flags is clearly insufficient, maybe not for you and me and other
> devs, but for the majority of our users. Note that this is not the
> same as optionally adding more specific documentation on a global flag
> in the metadata.xml of a package.

Most of the time when I see complaints about the description of USE
flags (I'm fully aware of those) the issue isn't the format, just that
noone else has come up with a better description. And technically
use.desc isn't limited to "a few words", unless you want to add
multiple paragraphs with formatting, just the (current) presentation
would get a bit ugly with longer descriptions. Of course the format
could be changed if needed, but that needs a more specific description
about the requirements.

> > and get rid of the stupid separation of "local" and "global" flags
> 
> Good idea. How do you plan to cope with the (currently) local USE flag
> conflicts though ?

You mean different descriptions? Just use a placeholder in use.desc
(like some global flags already have) and move the actual description
in metadata.xml if there isn't any common base.

Marius
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[gentoo-dev] Re: USE flag documentation

[Duncan]

Marius Mauch <genone@gentoo.org> posted
20080101060928.2a500186.genone@gentoo.org, excerpted below, on  Tue, 01
Jan 2008 06:09:28 +0100:

> Most of the time when I see complaints about the description of USE
> flags (I'm fully aware of those) the issue isn't the format, just that
> noone else has come up with a better description.

There are, I believe, two complaints, but one you don't see often as many 
don't think it's currently possible with a global USE flag (and possible 
but seldom done with local flags).

The first complaint is poor descriptions in general.  "foo - Adds foo 
support" just doesn't cut it.  (See USE=glw, for instance.  USE=gif's 
"Adds GIF image support" is at least somewhat better, saying GIF is an 
image format, at least.  I haven't a clue what libGlw does, except that 
it says requires mesa, which I know is 3D, so I suppose it's related to 
that, but what if someone doesn't know what mesa is?)  This seems to be 
the one you are addressing.

The second complaint, a frustration I often find myself experiencing, is 
that particularly with global flags, it's difficult to see exactly what 
they do in a particular package without actually seeing what the ebuild 
does.  Does it add the dependency and link against it?  Does it install 
example code and/or documentation for it?  Does it install bindings for 
it?  Is it build (static) against the included version vs using the 
system copy?  Does it not change what's supported at all, only the 
library/codec implementation used to handle it (the case with mp3/lame/
whatever sometimes)?  Etc.

It'd sure be nice to be able to run an euse -i flag and get the details 
of what flag actually does for various packages, or euse -i flag package, 
and get the info for just that package.  It'd be /real/ nice if emerge 
had a -vv or -vvv mode, that spit out what all the use flags actually did 
for those packages, at the detail level of the questions above.  If 
whatever proposal makes that easier, I say go for it. =8^)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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[gentoo-dev] USE flag documentation

[Mark Loeser]

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Here is a newer revision of the GLEP.  I still have multiple methods of
solving this problem (mostly because I want and *need* input from people
as to what they would prefer).  Please tell me what you would want to
use so I can come up with a more precise specification.  What exactly do
we need this system to do that we can't do now?  Is overriding the USE
flag with use.local.desc sufficient and we just need to document the
current solution properly?

Please...let me know how you feel about this.

http://dev.gentoo.org/~halcy0n/gleps/glep-0054.html

Thanks,

-- 
Mark Loeser
email         -   halcy0n AT gentoo DOT org
email         -   mark AT halcy0n DOT com
web           -   http://www.halcy0n.com

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Re: [gentoo-dev] USE flag documentation

[Yuri Vasilevski]

Hello,

On Sun, 13 Jan 2008 20:24:53 -0500
Mark Loeser <halcy0n@gentoo.org> wrote:

> What exactly do we need this system to do that we can't do now?

The only interesting thing I can think of, is to expose some of the USE
flags logic found in some ebuilds in a parseable fashion.

I'm talking about things like (from mplayer-1.0_rc2_p24929-r2.ebuild):

- Two flags are mutually exclusive:
  ( cdio implies !cdparanoia ) and (cdparanoia implies !cdio)
- A flag makes sense only if another flag is on:
  !encode implies !aac

This way portage will be able to inform/warn the user automatically
that the set of USE flags the user has chosen really means some other
thing. Something like:

[ebuild   R   ] media-video/mplayer-1.0_rc2_p24929-r2  USE="X cdio -aac#1 -cdparanoia#2 -encode ..."

#1 aac needs encode
#2 cdio conflicts with cdparanoia

But this logic will have to be exposed on a .ebuild level.

> Is overriding the USE flag with use.local.desc sufficient and we just
> need to document the current solution properly?

I would say yes.

Also, what would we gain switching to xml?
The format as it is now is trivially parseable and human friendly.
While if the data is in xml format it will be less human friendly, as
well as, it will be harder to extract the information from shell
scripts.

Kindest regards,
Yuri.
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Re: [gentoo-dev] USE flag documentation

[Santiago M. Mola]

On 1/14/08, Yuri Vasilevski <yvasilev@gentoo.org> wrote:
>
> [ebuild   R   ] media-video/mplayer-1.0_rc2_p24929-r2  USE="X cdio -aac#1 -cdparanoia#2 -encode ..."
>
> #1 aac needs encode
> #2 cdio conflicts with cdparanoia

This can be implemented with use.desc/use.local.desc. Paludis already
does that by default.

> But this logic will have to be exposed on a .ebuild level.
>

I don't think this is worth an EAPI change, or adding new variables to
ebuilds. metada.xml USE flag documentation could be extended to cover
such cases if it's really needed... but is it?

-- 
Santiago M. Mola
Jabber ID: cooldwind@gmail.com
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Re: [gentoo-dev] USE flag documentation

[Santiago M. Mola]

On 1/14/08, Santiago M. Mola <coldwind@gentoo.org> wrote:
> On 1/14/08, Yuri Vasilevski <yvasilev@gentoo.org> wrote:
> >
> > [ebuild   R   ] media-video/mplayer-1.0_rc2_p24929-r2  USE="X cdio -aac#1 -cdparanoia#2 -encode ..."
> >
> > #1 aac needs encode
> > #2 cdio conflicts with cdparanoia
>
> This can be implemented with use.desc/use.local.desc. Paludis already
> does that by default.
>

Sorry. Paludis shows USE flags, and overrides definitions with use.local.desc.
But stuff like "aac needs encode"  and "cdio conflicts with
cdparanoia" should be something separate from USE flag documentation.
As you said, it should be handled at ebuild level.

-- 
Santiago M. Mola
Jabber ID: cooldwind@gmail.com
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Re: [gentoo-dev] USE flag documentation

[Vlastimil Babka]

Santiago M. Mola wrote:
> But stuff like "aac needs encode"  and "cdio conflicts with
> cdparanoia" should be something separate from USE flag documentation.

Well, at least until it's handled at ebuild level, local USE flag 
documentation can be used to explain the implications to the user 
beforehand (ewarns work too, but only after user tries to actually 
install the package).

VB
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Re: [gentoo-dev] USE flag documentation

[Piotr Jaroszyński]

On Monday 14 of January 2008 02:24:53 Mark Loeser wrote:
> Here is a newer revision of the GLEP.  I still have multiple methods of
> solving this problem (mostly because I want and *need* input from people
> as to what they would prefer).  Please tell me what you would want to
> use so I can come up with a more precise specification.  What exactly do
> we need this system to do that we can't do now?  Is overriding the USE
> flag with use.local.desc sufficient and we just need to document the
> current solution properly?
>
> Please...let me know how you feel about this.

Tbh, I don't have any issues with the current solution, but I may be missing 
something. "Rationale" doesn't seem to help though, afaics it is just saying 
that the current behaviour  needs to be documented and fwiw PMS draft covers 
this already:
http://dev.gentoo.org/~spb/pms.pdf - section 3.4.3

> http://dev.gentoo.org/~halcy0n/gleps/glep-0054.html

Please, don't use an already assigned GLEP number, it's a bit confusing. Note 
that 55 is taken as well.

-- 
Best Regards,
Piotr Jaroszyński
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Re: [gentoo-dev] USE flag documentation

[Mark Loeser]

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Piotr Jaroszyński <peper@gentoo.org> said:
> Tbh, I don't have any issues with the current solution, but I may be missing 
> something. "Rationale" doesn't seem to help though, afaics it is just saying 
> that the current behaviour  needs to be documented and fwiw PMS draft covers 
> this already:
> http://dev.gentoo.org/~spb/pms.pdf - section 3.4.3

Which is fine, but PMS is just a draft.  I'm trying to see if everyone
can accept one solution, instead of throwing things into metadata.xml
and into use.local.desc without the process being documented in one place.
This is more of a proposal to see if we should even change how we do things
today.  Maybe we shouldn't, and that's what I'm trying to figure out...

> > http://dev.gentoo.org/~halcy0n/gleps/glep-0054.html
> 
> Please, don't use an already assigned GLEP number, it's a bit confusing. Note 
> that 55 is taken as well.

It wasn't taken when I first sent it (as far as I know).  I forgot to
change before resending.  Thanks for reminding me.

Thanks,

-- 
Mark Loeser
email         -   halcy0n AT gentoo DOT org
email         -   mark AT halcy0n DOT com
web           -   http://www.halcy0n.com

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