Re: mtl-2.1 severly broken, cabal needs blacklisting

14 Nov 2012

      On Tue, Nov 13, 2012 at 11:39 PM, Andreas Abel wrote:
...
On 13.11.12 11:13 PM, Jean-Philippe Bernardy wrote:
...
Blacklisting equals releasing a bugfix.
Not quite.
I propose to *define* blacklisting as such.

package-X.Y.Z.W is blacklisted if there exists package-X.Y.Z.V where V > W
(maybe I'm off by one position in the  version number scheme here, but you
get the idea)

The advantages of this proposal are
 * backward and forward compatible with all existing code, including hackage
 * minimal addition to cabal-install: add some code to detect compilation
against a blacklisted version
...
Warnings are easily overlooked.  In a typical cabal install session I see
tons of irrelevant warnings floating by.
WARNING: This package is compiled against known incorrect code! You should
upgrade the mtl package.

would show up at *every compilation*.

I am guessing this would have been sufficient to save you from a 250-module
shrinking.

By the way, the new warning is effective only if one has an up-to-date list
of packages.
Hence it makes sense to group it with the current warning about an
out-of-date list.

Cheers,
JP.
...
On Nov 13, 2012 6:12 PM, "Andreas Abel" 
...
>> wrote:
On 13.11.2012 17:39, Dan Burton wrote:
Mixed feelings here. I personally subscribe to the philosophy of
        "do one
        thing and do it well"; perhaps this sort of functionality would be
        better delegated to a new "curation" tool such as the one
        described in
        Michael Snoyman's recent blog post.
        http://www.yesodweb.com/blog/_**_2012/11/solving-cabal-hellhttp://www.yesodweb.com/blog/__2012/11/solving-cabal-hell
<http://www.yesodweb.com/blog/**2012/11/solving-cabal-hellhttp://www.yesodweb.com/blog/2012/11/solving-cabal-hell
...
I think Michael Snoyman's approach goes farther than mine and solves
    a slightly different problem.  I am not concerned with the
    "dependency hell" but with a means of safely avoiding bugged packages.
Uploading a bugged package can happen to anyone of us, but
    cabal/hackage does not provide a suitable means to rectify the
    situation.  Cabal's philosophy currently includes a monotonicity
    assumption: newer is better and more correct.  As a consequence,
    packages do not get removed or replaced since that could break
    compilation of other packages depending on a special version number
    of a package.  The calamity is that bugged package live on, and
    cabal install is oblivious of this.
If one could blacklist a certain version of a package, cabal could
    pick the next higher available version, as a sort of redirection
    mechanism to the fixed package.  For instance, if I have issued
mylib-2.1
       mylib-2.2
       mylib-3.0
and I discover a bug in mylib-2.1, I could blacklist mylib-2.1 and
    upload a bugfix version
mylib-2.1.1
that would be picked by cabal instead of mylib-2.1.
Those user packages that rely on the specific interface of mylib-2.1
    (e.g. having a constraint mylib == 2.1) and do not work with
    mylib-2.2 would still work, since they would be built with mylib-2.1.1
On Tue, Nov 13, 2012 at 9:27 AM, Andreas Abel

...

>>>
wrote:
After 2 days of shrinking 251 modules of source code to a
        few lines
             I realized that modify in MonadState causes <<loop>> in
        mtl-2.1.
http://hackage.haskell.org/___**_packages/archive/mtl/2.1/doc/**
____html/src/Control-Monad-**State-____Class.html#modifyhttp://hackage.haskell.org/____packages/archive/mtl/2.1/doc/____html/src/Con...
        <http://hackage.haskell.org/__**packages/archive/mtl/2.1/doc/_**
_html/src/Control-Monad-State-**__Class.html#modifyhttp://hackage.haskell.org/__packages/archive/mtl/2.1/doc/__html/src/Control...
...
<http://hackage.haskell.org/__**packages/archive/mtl/2.1/doc/_**
_html/src/Control-Monad-State-**__Class.html#modifyhttp://hackage.haskell.org/__packages/archive/mtl/2.1/doc/__html/src/Control...
        <http://hackage.haskell.org/**packages/archive/mtl/2.1/doc/**
html/src/Control-Monad-State-**Class.html#modifyhttp://hackage.haskell.org/packages/archive/mtl/2.1/doc/html/src/Control-Mon...
...
...
The bug has been fixed, apparently seven month ago.
https://github.com/ekmett/mtl/**____pull/1https://github.com/ekmett/mtl/____pull/1
        <https://github.com/ekmett/**mtl/__pull/1https://github.com/ekmett/mtl/__pull/1
...
<https://github.com/ekmett/__**mtl/pull/1https://github.com/ekmett/__mtl/pull/1
        <https://github.com/ekmett/**mtl/pull/1https://github.com/ekmett/mtl/pull/1
...
...
However, the "malicious" mtl-2.1 still lingers on: it is
        available
             from hackage and installed in many systems.
This calls for a means of blacklisting broken or malicious
        packages.
cabal update
should also pull a blacklist of packages that will never be
        selected
             by cabal install (except maybe by explicit user safety
        overriding).
I think such a mechanism is not only necessary for security
             purposes, but also to safe the valuable resources of our
        community.
Cheers,
             Andreas
--
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Andreas Abel  <><      Du bist der geliebte Mensch.
Theoretical Computer Science, University of Munich
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