Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Mike Hommey]

On Fri, Aug 27, 2010 at 07:08:08PM -0400, Felipe Sateler wrote:
> > AFAIK, the current version of dpkg in stable supports symbols files, so
> > I think it is time we loosen the requirement for shlibs files when
> > symbols files are present.
> > 
> > Requiring shlibs when there is a symbols file also is error-prone,
> > as when the symbols file is updated, the shlibs may not be bumped.
> 
> dpkg-shlibdeps(1) says:
> 
> > Then, for each library, it looks up either  the
> > symbols  file,  or  the  shlibs file (if the former doesn't exist or if
> > debian/shlibs.local contains the relevant dependency).
> 
> So if you have a symbols file, the shlibs file is redundant.

Except if you use an old dpkg-shlibdeps, in which case if the shlibs is
not updated correctly, you get the wrong info. But my point was that an
old enough dpkg-shlibdeps is already old, and that it's time to maybe
change the rules and get rid of shlibs when there is a symbols file.

Mike



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Russ Allbery]

Summary: Debian Policy should gain documentation of the symbols file
format and a description of symbols in section 8.6 before shlibs, since
symbols are preferred where usable.  The shlibs documentation should
remain, since shlibs are still required for udebs and are still widely
used in cases where writing symbols files is hard or spurious changes to
the exported symbols happen in ways that don't break library compatibility
for normal use (C++, for example).  The format information should be taken
from deb-symbols(5) and refer to (but not document here) dpkg-gensymbols
for the other things one can do during symbol generation time.  shlibs
files should probably be optional if symbols files are present, but there
will probably be further discussion of that.

I believe this bug (and the merged bug) are just waiting for someone to
have time to write that language, so I'm tagging them both proposal.  (And
testing out the new BTS summary feature with this message.)

-- 
Russ Allbery (r...@debian.org)   



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Goswin von Brederlow]

Russ Allbery  writes:

> Raphael Hertzog  writes:
>
>> Russ, dpkg-gensymbols could be modified to do that shlibs
>> generation. Feel free to file a wishlist request against dpkg-dev.
>
> Will do.  Thanks!  I agree with Mike that for people already maintaining a
> symbols file, this would be very useful to do automatically during the
> build and remove a source of possible errors and inconsistency.

But what for?

The symbol file doesn't work for udebs because it lacks the udeb
entries. But then the automatic conversion will also lack those entries
and nothing has been won. And if you don't have udebs then the symbols
file is already sufficient for all features and the shlibs adds nothing.

Given a correct symbol files the shlibs file, manually or automatically
generated, gains nothing. It only adds the possibility of the shlibs
file being wrong. So why not allow libraries to have symbol files only?
That wouldn't even need any tool to change at all. Just some words in
policy.

MfG
Gowin



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Russ Allbery]

Raphael Hertzog  writes:

> Russ, dpkg-gensymbols could be modified to do that shlibs
> generation. Feel free to file a wishlist request against dpkg-dev.

Will do.  Thanks!  I agree with Mike that for people already maintaining a
symbols file, this would be very useful to do automatically during the
build and remove a source of possible errors and inconsistency.

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Russ Allbery (r...@debian.org)   



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Raphael Hertzog]

On Mon, 01 Mar 2010, Goswin von Brederlow wrote:
> Russ Allbery  writes:
> 
> > Mike Hommey  writes:
> >
> >> I first though having dh_makeshlibs do the right thing would be good
> >> enough, but that would also put an unnecessary burden on those that
> >> don't use debhelper.
> >
> > Is there any way that dpkg-gensymbols could do it (perhaps with extra
> > arguments)?
> 
> The symbol files uses the full soname so it allows for libraries where
> shlibs files fail because the soname has an unexpected pattern.
> 
> So while it could possible do it most times it can't do it all the time.

Anything that is covered by shlibs and symbols can have it shlibs part
generated from the symbols information. That's all that matters for this
discussion.

We're speaking of existing shlibs files, not of those that cannot exist.

Russ, dpkg-gensymbols could be modified to do that shlibs generation. Feel
free to file a wishlist request against dpkg-dev.

Cheers,
-- 
Raphaël Hertzog

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My Debian goals: http://ouaza.com/wp/2010/01/09/debian-related-goals-for-2010/



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Goswin von Brederlow]

Russ Allbery  writes:

> Mike Hommey  writes:
>
>> I first though having dh_makeshlibs do the right thing would be good
>> enough, but that would also put an unnecessary burden on those that
>> don't use debhelper.
>
> Is there any way that dpkg-gensymbols could do it (perhaps with extra
> arguments)?

The symbol files uses the full soname so it allows for libraries where
shlibs files fail because the soname has an unexpected pattern.

So while it could possible do it most times it can't do it all the time.

MfG
Goswin



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Russ Allbery]

Mike Hommey  writes:

> I first though having dh_makeshlibs do the right thing would be good
> enough, but that would also put an unnecessary burden on those that
> don't use debhelper.

Is there any way that dpkg-gensymbols could do it (perhaps with extra
arguments)?

-- 
Russ Allbery (r...@debian.org)   



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Raphael Hertzog]

On Mon, 01 Mar 2010, Mike Hommey wrote:
> On Sun, Feb 28, 2010 at 11:29:52AM +0100, Julien Cristau wrote:
> > On Mon, Feb 22, 2010 at 09:34:50 +0100, Mike Hommey wrote:
> > 
> > > Package: debian-policy
> > > Version: 3.8.4.0
> > > Severity: wishlist
> > > 
> > > AFAIK, the current version of dpkg in stable supports symbols files, so I
> > > think it is time we loosen the requirement for shlibs files when symbols
> > > files are present.
> > > 
> > > Requiring shlibs when there is a symbols file also is error-prone, as when
> > > the symbols file is updated, the shlibs may not be bumped.
> > > 
> > Agreed, but with the caveat that libs shipping an udeb need to keep
> > their .shlibs file, afaik.
> 
> symbols files don't support udebs ?

dpkg-shlibdeps only looks up shlibs for udebs. That's because shlibs for
udebs are provided by the normal library package.

Having the library provide two variants of symbols files (one for the udeb
and one for the main package) was not something I was interested in
implementing given that udebs are coherent set of packages and are not so
frequently mixed between multiple releases.

Cheers,
-- 
Raphaël Hertzog

Like what I do? Sponsor me: http://ouaza.com/wp/2010/01/05/5-years-of-freexian/
My Debian goals: http://ouaza.com/wp/2010/01/09/debian-related-goals-for-2010/



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Mike Hommey]

On Sun, Feb 28, 2010 at 11:29:52AM +0100, Julien Cristau wrote:
> On Mon, Feb 22, 2010 at 09:34:50 +0100, Mike Hommey wrote:
> 
> > Package: debian-policy
> > Version: 3.8.4.0
> > Severity: wishlist
> > 
> > AFAIK, the current version of dpkg in stable supports symbols files, so I
> > think it is time we loosen the requirement for shlibs files when symbols
> > files are present.
> > 
> > Requiring shlibs when there is a symbols file also is error-prone, as when
> > the symbols file is updated, the shlibs may not be bumped.
> > 
> Agreed, but with the caveat that libs shipping an udeb need to keep
> their .shlibs file, afaik.

symbols files don't support udebs ?

Mike



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Mike Hommey]

On Sun, Feb 28, 2010 at 01:52:15PM +0100, Bernhard R. Link wrote:
> * Mike Hommey  [100227 23:53]:
> > AFAIK, the current version of dpkg in stable supports symbols files, so I
> > think it is time we loosen the requirement for shlibs files when symbols
> > files are present.
> >
> > Requiring shlibs when there is a symbols file also is error-prone, as when
> > the symbols file is updated, the shlibs may not be bumped.
> 
> Perhaps creating shlibs files out of symbols files at build time could
> also be a solution for this.

I first though having dh_makeshlibs do the right thing would be good
enough, but that would also put an unnecessary burden on those that
don't use debhelper.

Mike



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Russ Allbery]

"Bernhard R. Link"  writes:
> * Mike Hommey  [100227 23:53]:

>> AFAIK, the current version of dpkg in stable supports symbols files, so
>> I think it is time we loosen the requirement for shlibs files when
>> symbols files are present.

>> Requiring shlibs when there is a symbols file also is error-prone, as when
>> the symbols file is updated, the shlibs may not be bumped.

> Perhaps creating shlibs files out of symbols files at build time could
> also be a solution for this.

Yeah.. while I have nothing to really back this up and know of no software
that would be affected, I'm minorly reluctant to remove completely an
interface that Debian's supported for so long.  It feels like good design
in the abstract to know that every shared library has a shlibs file still,
since symbols files can't completely replace them.

This is just a gut feeling thing and doesn't have any hard data behind it,
but auto-generating the shlibs file would resolve the motivating reason
behind the original bug, I think, and not lose the interface.

-- 
Russ Allbery (r...@debian.org)   



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Bernhard R. Link]

* Mike Hommey  [100227 23:53]:
> AFAIK, the current version of dpkg in stable supports symbols files, so I
> think it is time we loosen the requirement for shlibs files when symbols
> files are present.
>
> Requiring shlibs when there is a symbols file also is error-prone, as when
> the symbols file is updated, the shlibs may not be bumped.

Perhaps creating shlibs files out of symbols files at build time could
also be a solution for this.

Hochachtungsvoll,
Bernhard R. Link
-- 
"Never contain programs so few bugs, as when no debugging tools are available!"
Niklaus Wirth



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Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Julien Cristau]

On Mon, Feb 22, 2010 at 09:34:50 +0100, Mike Hommey wrote:

> Package: debian-policy
> Version: 3.8.4.0
> Severity: wishlist
> 
> AFAIK, the current version of dpkg in stable supports symbols files, so I
> think it is time we loosen the requirement for shlibs files when symbols
> files are present.
> 
> Requiring shlibs when there is a symbols file also is error-prone, as when
> the symbols file is updated, the shlibs may not be bumped.
> 
Agreed, but with the caveat that libs shipping an udeb need to keep
their .shlibs file, afaik.

Cheers,
Julien


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Description: Digital signature

Bug#571776: debian-policy: Libraries should be allowed to not provide shlibs when they provide symbols file

[Mike Hommey]

Package: debian-policy
Version: 3.8.4.0
Severity: wishlist

AFAIK, the current version of dpkg in stable supports symbols files, so I
think it is time we loosen the requirement for shlibs files when symbols
files are present.

Requiring shlibs when there is a symbols file also is error-prone, as when
the symbols file is updated, the shlibs may not be bumped.

Cheers,

Mike


-- System Information:
Debian Release: squeeze/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.31-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

debian-policy depends on no packages.

debian-policy recommends no packages.

Versions of packages debian-policy suggests:
pn  doc-base   (no description available)

-- no debconf information



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