[web-devel] GHCi runtime linker: fatal error: I found a duplicate definition for symbol (Yesod)

[vagif.verdi at gmail.com]

Thank you Michael! I just tried new wai-handler-devel and it works like a 
charm!

On Wednesday, March 23, 2011 11:54:50 PM you wrote:
> What Blake suggests in the right solution, except for two points
> (which are beyond his control):
> 
> * It's a bit unfair to make users remember to install yesod with
> -fproduction. * wai-handler-devel does not handle Hamlet dependency
> tracking. That means that if you use Blake's suggestion and then modify
> your Hamlet templates, your code will not be reloaded.
> 
> So I've released new versions of wai-handler-devel (0.2.1) and yesod
> (0.7.2). There's no such thing as the -fproduction flag to yesod: it
> will never build against wai-handler-devel. When you call the
> develServer function, it will simply print out a message apologizing
> that it cannot fulfill your request, and will tell you to install
> wai-handler-devel >= 0.2.1 and run a command such as:
> 
>    wai-handler-devel 3000 Controller withTest --yesod
> 
> Notice that extra --yesod at the end? That's the new feature in 0.2.1.
> I moved the Hamlet dependency checking code from yesod to
> wai-handler-devel. So now, if you run your application this way,
> Hamlet changes will automatically result in a reload of your code.
> 
> I tried to set up the develServer function to automatically run
> wai-handler-server, but it resulted in the same error messages from
> GHC. Oh well. I image in future versions of the scaffolding tool, the
> devel-server.hs function will do all this for you automatically.
> 
> Please let me know if this new approach causes any issues.
> 
> Michael
> 
> On Thu, Mar 24, 2011 at 1:00 AM, Blake Rain <blake.rain at gmail.com> wrote:
> > I too had a the same problem with duplicate symbols from libHSghc, and
> > it seems to be a problem with yesod's dynamic server (or perhaps with
> > Hint).
> > 
> > My solution was first to remove the dependency on wai-handler-devel in
> > the yesod package by using the 'production' flag, like so:
> > 
> > $ cabal install yesod -fproduction
> > 
> > For running a dynamic server, the wai-handler-devel package installs an
> > executable called wai-handler-devel. You can use this rather than the
> > "runhaskell devel-server.hs" by providing the port, module and function
> > from your "devel-server.hs" file as arguments:
> > 
> > $ wai-handler-devel 3000 MySiteModule withMySite
> > 
> > The dynamic recompilation of wai-handler-devel is very useful, and I
> > hope this helps.
> > 
> > On Wed, 2011-03-23 at 14:22 -0400, Rick Richardson wrote:
> >> I removed all but network-2.2.1.0 and rebuilt everything, still no
> >> luck. But I'm sure you have set me on the right track, I will
> >> experiment with other permutations.
> >> 
> >> 
> >> Thanks.
> >> 
> >> 
> >> 
> >> 
> >> On Wed, Mar 23, 2011 at 1:27 PM, Anton Cheshkov <acheshkov at gmail.com>
> >> wrote:
> >>         Hi Rick! I got the the same error day ago on my server.
> >>         Probably it happens because you have two network packages in
> >>         you system.
> >> 
> >>         Try to compile all your packages  only on  network-2.2.1.10,
> >>         and delete package network-2.3
> >> 
> >> 
> >>         Hope it helps you
> >> 
> >> 
> >>         2011/3/23 Rick Richardson <rick.richardson at gmail.com>
> >> 
> >> 
> >> 
> >>                 I just installed the generic 7.0.2 binary on Ubuntu
> >>                  on both 32 bit and 64 bit machines.  Then I rm'd
> >>                   .ghc and .cabal  then fetched the current haskell
> >>                 platform. Built and installed.
> >> 
> >> 
> >>                 After cabal installing all of the dependencies cabal
> >>                 said were required for yesod,  I run yesod.. the
> >>                 script creates the project.
> >> 
> >> 
> >>                 When executing runhaskell devel-server.hs  I get this
> >>                 message
> >> 
> >> 
> >>                 GHCi runtime linker: fatal error: I found a duplicate
> >>                 definition for symbol
> >>                    ghczm7zi0zi2_AsmCodeGen_zdfMonadCmmOptM2_closure
> >>                 whilst processing object file
> >> 
> >>                  /usr/local/lib/ghc-7.0.2/ghc-7.0.2/libHSghc-7.0.2.a
> >>                 This could be caused by:
> >>                    * Loading two different object files which export
> >>                 the same symbol
> >>                    * Specifying the same object file twice on the GHCi
> >>                 command line
> >>                    * An incorrect `package.conf' entry, causing some
> >>                 object to be
> >>                      loaded twice.
> >>                 GHCi cannot safely continue in this situation.
> >>                  Exiting now.  Sorry.
> >> 
> >> 
> >> 
> >> 
> >>                 it's the same on both 32 and 64 bit.
> >> 
> >> 
> >>                 Any ideas?   I am going to try to build 7.0.2 from
> >>                 source to see if that fixes it.
> >> 
> >> 
> >>                 _______________________________________________
> >>                 web-devel mailing list
> >>                 web-devel at haskell.org
> >>                 http://www.haskell.org/mailman/listinfo/web-devel
> >> 
> >> 
> >> 
> >> 
> >>         --
> >>         Best regards,
> >>         Cheshkov Anton
> >>         Phone: +7 909 005 18 82
> >>         Skype: cheshkov_anton
> >> 
> >> 
> >> 
> >> _______________________________________________
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> >> web-devel at haskell.org
> >> http://www.haskell.org/mailman/listinfo/web-devel
> > 
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