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Today's Topics:
1. Re: Cabal: Upgrading to the latest version of library
(Daniel Fischer)
2. Re: Cabal: Upgrading to the latest version of library
(Hugo Ferreira)
3. Re: Cabal: Upgrading to the latest version of library
(Giovanni Tirloni)
4. Re: Cabal: Upgrading to the latest version of library
(Rustom Mody)
----------------------------------------------------------------------
Message: 1
Date: Tue, 1 Nov 2011 13:07:50 +0100
From: Daniel Fischer <daniel.is.fisc...@googlemail.com>
Subject: Re: [Haskell-beginners] Cabal: Upgrading to the latest
version of library
To: beginners@haskell.org
Message-ID: <201111011307.50409.daniel.is.fisc...@googlemail.com>
Content-Type: Text/Plain; charset="iso-8859-1"
On Tuesday 01 November 2011, 11:50:45, Hugo Ferreira wrote:
> Hello,
>
> Recently I had to update and install a newer version of a library.
> I executed the "cabal update", which downloads the latest package list.
> I had assumed that this command would also detect, build and install
> those libraries that have been upgraded. However this does not seem to
> be the case. I had to manually build the library and then use GHC's
> package manager do unregister the old version.
Unregistering the old version is not necessary, different versions of the
same package can coexist. However, if some of the installed packages depend
on the old version and some on the newer, those packages can generally not
be used together, so unregistering is safer.
>
> My question is: how does one check for and upgrade the cabal libraries
> automatically?
Not.
1. It's not possible to do it automatically since the latest versions of
some packages can have incompatible dependencies, e.g. the latest foo
depends on bar >= x.y && < x.(y+1), the latest baz however depends on bar
>= x.(y+1).
Then you can't have foo together with the latest baz.
2. Usually, some not-updated packages depend on updated packages. Even if
no incompatibility as above is introduced, that would cause a *lot* of
recompilation and reinstallation. You don't inflict that on users unless
they explicitly ask for it.
3. Often there's no real point in upgrading packages. Say the widely used
package quux-x.y.z.d (think of something like text) had a typo in the
haddocks, author fixes and uploads quux-x.y.z.e; thanks for recompiling my
entire set of installed packages. Or a minor addition to the API that you
don't need. Or a fix in a CPP macro that doesn't affect you, ...
Installation of newer versions of packages you already have should be a
conscious decision by you, after pondering the consequences.
------------------------------
Message: 2
Date: Tue, 01 Nov 2011 16:04:12 +0000
From: Hugo Ferreira <h...@inescporto.pt>
Subject: Re: [Haskell-beginners] Cabal: Upgrading to the latest
version of library
Cc: beginners@haskell.org
Message-ID: <4eb0187c.30...@inescporto.pt>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
On 11/01/2011 12:07 PM, Daniel Fischer wrote:
> On Tuesday 01 November 2011, 11:50:45, Hugo Ferreira wrote:
>> Hello,
>>
>> Recently I had to update and install a newer version of a library.
>> I executed the "cabal update", which downloads the latest package list.
>> I had assumed that this command would also detect, build and install
>> those libraries that have been upgraded. However this does not seem to
>> be the case. I had to manually build the library and then use GHC's
>> package manager do unregister the old version.
>
> Unregistering the old version is not necessary, different versions of the
> same package can coexist. However, if some of the installed packages depend
> on the old version and some on the newer, those packages can generally not
> be used together, so unregistering is safer.
>
Ok.
>>
>> My question is: how does one check for and upgrade the cabal libraries
>> automatically?
>
> Not.
>
> 1. It's not possible to do it automatically since the latest versions of
> some packages can have incompatible dependencies, e.g. the latest foo
> depends on bar>= x.y&& < x.(y+1), the latest baz however depends on bar
>> = x.(y+1).
>
> Then you can't have foo together with the latest baz.
>
> 2. Usually, some not-updated packages depend on updated packages. Even if
> no incompatibility as above is introduced, that would cause a *lot* of
> recompilation and reinstallation. You don't inflict that on users unless
> they explicitly ask for it.
>
> 3. Often there's no real point in upgrading packages. Say the widely used
> package quux-x.y.z.d (think of something like text) had a typo in the
> haddocks, author fixes and uploads quux-x.y.z.e; thanks for recompiling my
> entire set of installed packages. Or a minor addition to the API that you
> don't need. Or a fix in a CPP macro that doesn't affect you, ...
>
> Installation of newer versions of packages you already have should be a
> conscious decision by you, after pondering the consequences.
>
I must confess I am a little disappointed. :-(
I have used Ocaml + the GODI "package manager" and it seems work ok.
GODI allows one to identify newer packages, select those we want to
upgrade and recompiles any dependencies automatically.
Thanks for the info.
Hugo F.
------------------------------
Message: 3
Date: Tue, 1 Nov 2011 18:01:45 -0200
From: Giovanni Tirloni <gtirl...@sysdroid.com>
Subject: Re: [Haskell-beginners] Cabal: Upgrading to the latest
version of library
To: Hugo Ferreira <h...@inescporto.pt>
Cc: beginners@haskell.org
Message-ID:
<caj9aok--ay-2k6yptgepg3q39_a-wd5xoajwqw3h+ydcu6w...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
On Tue, Nov 1, 2011 at 2:04 PM, Hugo Ferreira <h...@inescporto.pt> wrote:
>
> I have used Ocaml + the GODI "package manager" and it seems work ok.
> GODI allows one to identify newer packages, select those we want to
> upgrade and recompiles any dependencies automatically.
>
>
As a newcommer, I feel that this subject has already been discussed at
length by the Haskell community and progress is being made.
Two articles that I have been referred to in order to understand it better:
http://www.vex.net/~trebla/haskell/sicp.xhtml#unsafeInterleave
http://ivanmiljenovic.wordpress.com/2010/03/15/repeat-after-me-cabal-is-not-a-package-manager/
As a Fedora user, I'm relying on the Haskell SIG work and using the ghc-*
RPM packages. When a given Hackage package has not been packaged in Fedora
yet, I'm using cabal to supplement but I think that's sub-optimal (from a
sysadmin perspective). I'm looking at ways to actually build my own RPMs
following their standards. As it's mentioned in one of the article, someone
has had the trouble to figure out which packages work best together.
I second Daniel's opinion that updates should be a conscious decision on
the part of the developer. The kind of dependency problems exemplified are
not restricted to cabal and apply as well to PHP's Pear, Perl's CPAN and
others. What I usually see is that developers try to guarantee their
packages will correctly work with a given set of dependencies and so they
specify minimum and maximum versions of those as restrictions. Obviously,
easing those restrictions would ensure it's easier to match package but who
guarantees they'll work (i.e. no important API change) ?
My own experience managing packages in PHP hosting environments tells me
that, even though the package manager was happy to upgrade everything I
told it to.. I would usually find the interfacing problems myself in the
form of downtime. In that scenario, I would prefer both a package more
strictly defined in terms of dependencies. In cabal/Haskell things won't
even compile, which is good :-)
Any, just 0.02 from a newbie.
Giovanni
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Message: 4
Date: Wed, 2 Nov 2011 08:35:07 +0530
From: Rustom Mody <rustompm...@gmail.com>
Subject: Re: [Haskell-beginners] Cabal: Upgrading to the latest
version of library
To: Giovanni Tirloni <gtirl...@sysdroid.com>
Cc: beginners@haskell.org
Message-ID:
<caj+teoc-93khqwjyczex5goecrcejk222f-2ek1tijkqaue...@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
On Wed, Nov 2, 2011 at 1:31 AM, Giovanni Tirloni <gtirl...@sysdroid.com>wrote:
> On Tue, Nov 1, 2011 at 2:04 PM, Hugo Ferreira <h...@inescporto.pt> wrote:
>>
>> I have used Ocaml + the GODI "package manager" and it seems work ok.
>> GODI allows one to identify newer packages, select those we want to
>> upgrade and recompiles any dependencies automatically.
>>
>>
> As a newcommer, I feel that this subject has already been discussed at
> length by the Haskell community and progress is being made.
>
> Two articles that I have been referred to in order to understand it better:
>
> http://www.vex.net/~trebla/haskell/sicp.xhtml#unsafeInterleave
>
> http://ivanmiljenovic.wordpress.com/2010/03/15/repeat-after-me-cabal-is-not-a-package-manager/
>
>
Thanks for those links.
> As a Fedora user, I'm relying on the Haskell SIG work and using the ghc-*
> RPM packages. When a given Hackage package has not been packaged in Fedora
> yet, I'm using cabal to supplement but I think that's sub-optimal (from a
> sysadmin perspective). I'm looking at ways to actually build my own RPMs
> following their standards. As it's mentioned in one of the article, someone
> has had the trouble to figure out which packages work best together.
>
I wonder if you could throw some light on this?
Say you just have to use the 'sub-optimal' solution and cabal install some
package foo.
Later it appears in the rpm list and you can yum install it.
How do you now cabal uninstall foo?
>
> I second Daniel's opinion that updates should be a conscious decision on
> the part of the developer. The kind of dependency problems exemplified are
> not restricted to cabal and apply as well to PHP's Pear, Perl's CPAN and
> others. What I usually see is that developers try to guarantee their
> packages will correctly work with a given set of dependencies and so they
> specify minimum and maximum versions of those as restrictions. Obviously,
> easing those restrictions would ensure it's easier to match package but who
> guarantees they'll work (i.e. no important API change) ?
>
> My own experience managing packages in PHP hosting environments tells me
> that, even though the package manager was happy to upgrade everything I
> told it to.. I would usually find the interfacing problems myself in the
> form of downtime. In that scenario, I would prefer both a package more
> strictly defined in terms of dependencies. In cabal/Haskell things won't
> even compile, which is good :-)
>
> Any, just 0.02 from a newbie.
>
> Giovanni
>
> _______________________________________________
> Beginners mailing list
> Beginners@haskell.org
> http://www.haskell.org/mailman/listinfo/beginners
>
>
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