Duplicate symbol error when loading text twice

We are developing some FFI binding to some Kinect Camera library, and came across the following:

GHCi, version 7.6.3: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Prelude> import Honi
Prelude Honi> import Honi.Types
Prelude Honi Honi.Types> initialize 2
Loading package array-0.4.0.1 ... linking ... done.
Loading package deepseq-1.3.0.1 ... linking ... done.
Loading package bytestring-0.10.0.2 ... linking ... done.
Loading package text-0.11.3.1 ... linking ... done.
Loading package honi-0.1.0.0 ... can't load .so/.DLL for: libfreenect.so (libfreenect.so: cannot open shared object file: No such file or directory)
Prelude Honi Honi.Types> Right [d] <- getDeviceList
Loading package array-0.4.0.1 ... linking ... done.
Loading package deepseq-1.3.0.1 ... linking ... done.
Loading package bytestring-0.10.0.2 ... linking ... done.
Loading package text-0.11.3.1 ... 

GHCi runtime linker: fatal error: I found a duplicate definition for symbol
   __stginit_textzm0zi11zi3zi1_DataziText
whilst processing object file
   /home/niklas/.cabal/lib/x86_64-linux-ghc-7.6.3/text-0.11.3.1/libHStext-0.11.3.1.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.

Apparently, ghci has no problem linking packages like array and deepseq twice, but when it comes across loading text another time, we get this duplicate symbol error.

Does this make sense? Why does it not detect that text is already linked, like for the other packages?

Trac metadata

Trac field	Value
Version	7.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

changed weight to 5

added Tbug Trac import labels

mentioned in issue #8942 (closed)

I tried cabal install honi, but am getting the error:

* Missing C libraries: OpenNI2, freenect

Where do I get those, for Ubuntu 14.04. Or better: could you construct a small program that doesn't use honi to reproduce this issue? Thanks.

Trac metadata

Trac field	Value
Related	→ #7030 (closed)

So, it turns out that there is a linking failure in the pasted transcript. So it looks like the bug is that we are not properly unloading the objects we loaded prior to the failure; namely, text has something which is not unloaded.

Trac metadata

Trac field	Value
Component	Compiler → Runtime System (Linker)

OK, so I tried to reproduce with a very minimal example, using the following steps:

1. I took honi, and edited it so it had no dependence on the actual libraries. I installed it, and then manually edited package config so that it had a dependency on a non-existent dynamic library.
2. Then I opened GHCi, and induced GHCi to attempt to load the packages twice (failing because this last package couldn't load the non-existent package.)

However, text reloaded fine for me. Granted, it was text-1.2.1.3 but I don't think there is any substantive difference here.

So yes, we are going to need more information to reproduce and solve this bug.

closed

OK, so first on how to get the deps:

• freenect: apt-get install libfreenect-dev on Ubuntu 14.04
• OpenNI2: git clone https://github.com/occipital/OpenNI2.git, cd OpenNI2, git checkout origin/develop

Then I compile with $HOME/.local/bin/cabal install --extra-include-dirs=$HOME/src/OpenNI2/Include/ --extra-lib-dirs=$HOME/src/OpenNI2/Bin/x64-Release/

However, I have tried this now with GHC 7.10.2, and cabal-install 1.22.6.0, and can no longer reproduce the issue.

My output:

➤ ghci
GHCi, version 7.10.2: http://www.haskell.org/ghc/  :? for help
Prelude> import Honi
Prelude Honi> import Honi.Types 
Prelude Honi Honi.Types> initialize 2
StatusOK

Trying the same with GHC 7.8:

~/.stack/programs/x86_64-linux/ghc-7.8.4/bin/ghc --interactive 
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Prelude> import Honi
Prelude Honi> import Honi.Types 
Prelude Honi Honi.Types> initialize 2
Loading package array-0.5.0.0 ... linking ... done.
Loading package deepseq-1.3.0.2 ... linking ... done.
Loading package bytestring-0.10.4.0 ... linking ... done.
Loading package containers-0.5.5.1 ... linking ... done.
Loading package binary-0.7.1.0 ... linking ... done.
Loading package text-1.2.1.3 ... linking ... done.
Loading package honi-0.1.0.0 ... linking ... done.
StatusOK

So I believe this was probably fixed with the linker improvements in GHC 7.8 (I reported the bug against 7.6).

Thanks for poking at this bug, I'm happy to find that it is fixed.

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed

added GHCi label

added Pnormal label