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On Sat, 2006-09-23 at 06:13 -0400, Mike Frysinger wrote: |
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> On Thursday 21 September 2006 11:41, Duncan Coutts wrote: |
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> > On Thu, 2006-09-21 at 11:11 -0400, Mike Frysinger wrote: |
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> > > On Thursday 21 September 2006 10:56, Duncan Coutts wrote: |
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> > > > If we do go in this direction it'd be great to be able to slot on the |
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> > > > ABI and still have dependencies resolved correctly. For example imagine |
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> > > > having parallel python-2.3 and 2.4 installations with some libs |
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> > > > installed for both. Crucially, deps need to be resolved to the version |
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> > > > of a lib with the right ABI. |
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> > > |
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> > > ugh, no ... we are not a binary distribution so we should not have to |
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> > > worry about ABI baggage |
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> > |
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> > So we can't ever install two versions of python or ghc at once? That |
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> > seems a shame. |
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> |
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> that's an issue for the python or ghc maintainers to address |
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Yes and as ghc maintainer for Gentoo I'd love to be able to do it. It is |
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easy to install more than one version of ghc at once as it uses |
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versioned directories etc. The problem is that we cannot correctly |
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resolve dependencies with the current versions of portage. Hence we |
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cannot effectively do it. |
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I was worried from your ABI/API comments that you meant that we should |
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never be allowed to do it. |
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As I said before, if we were to SLOT ghc and the various dev-haskell/* |
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libs on the ghc version then we would run into this problem: |
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assume dev-haskell/foo needs dev-haskell/bar |
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supposing dev-haskell/bar was installed and sloted for ghc-6.2 |
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now I install ghc-6.4 too |
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now I emerge dev-haskell/foo. |
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portage will use the existing installation of dev-haskell/bar even |
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though it was installed for another version of ghc. Therefore the build |
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will break (think of haskell libs of having a SONAME that is the version |
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of ghc they were built with). What needs to happen is to install |
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dev-haskell/bar sloted for ghc-6.4 and use that. |
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Currently there is no way to explain these dependencies to portage. |
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I was hoping that with this talk of tracking reverse deps and such like |
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that we could move in a direction where this kind of dependency could be |
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supported. Even if we can't slot on the ghc version, automatically |
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rebuilding for the latest ghc version would be a great improvement - |
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like the suggestion to rebuild dependent libs when the SONAME changes. |
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Duncan |
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-- |
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