[GHC] #11536: Multitude of different error messages when installed package is missing a module

3 Feb 2016

      #11536: Multitude of different error messages when installed package is missing a
module
-------------------------------------+-------------------------------------
           Reporter:  thomie         |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  7.10.3
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:  #8060, #9009,
                                     |  #11023
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 (I might clean this up later)

 Key points:
 * missing module in 'exposed-modules' field of .cabal file
 * package name equals some (functioning) installed package
 * ghc-pkg happily registers the package
 * errors don't show up until one tries to use the module
 * error messages are all different and all quite terrible

 Makefile to reproduce:
 {{{
 GHCPKG=ghc-pkg
 #GHC=ghc-8.0.0.20160127
 GHC=ghc-7.10.3
 PACKAGEDB=../.cabal-sandbox/x86_64-linux-$(GHC)-packages.conf.d/

 all :
         $(MAKE) --no-print-directory clean
         $(MAKE) --no-print-directory setup
         $(MAKE) --no-print-directory setup1
         $(MAKE) --no-print-directory run1

         @echo
         @echo

         $(MAKE) --no-print-directory clean
         $(MAKE) --no-print-directory setup
         $(MAKE) --no-print-directory setup2
         $(MAKE) --no-print-directory run2

 clean :
         rm -rf .cabal-sandbox cabal.sandbox.config
         rm -rf temp dist System *.cabal

 setup :
         mkdir temp
         mkdir -p System/FilePath
         cabal -v0 sandbox init

         echo "name:                filepath     " >> filepath.cabal
         echo "version:             99999.1.0    " >> filepath.cabal
         echo "build-type:          Simple       " >> filepath.cabal
         echo "cabal-version:       >=1.10       " >> filepath.cabal
         echo "library                           " >> filepath.cabal
         echo "  exposed-modules:                " >> filepath.cabal
         echo "    System.FilePath               " >> filepath.cabal
         echo "    System.FilePath.Posix         " >> filepath.cabal
         echo "  build-depends:       base >=4.8 " >> filepath.cabal
         echo "  default-language:    Haskell2010" >> filepath.cabal

         echo "module System.FilePath (module System.FilePath.Posix) where"
...
...
System/FilePath.hs
         echo "import System.FilePath.Posix                               "
System/FilePath.hs
echo "module System.FilePath.Posix where" >>
 System/FilePath/Posix.hs
         echo "takeFileName = id                 " >>
 System/FilePath/Posix.hs

 setup1 :
         @echo
         @echo 111111111111111111111111111111111
         @echo - Remove a module from 'exposed-modules'
         @echo - Install package
         @echo - Run some tests
         @echo
         sed -i '/System.FilePath.Posix/d' filepath.cabal
         cabal install -v0 --with-ghc="$(GHC)"

 run1 :
         @echo
         @echo FAILURE MODE 1A
         @echo
         -cd temp && "$(GHC)" -v0 -package-db="$(PACKAGEDB)" -e 'import
 System.FilePath.Posix'
         @echo
         @echo FAILURE MODE 1B
         @echo
         -cd temp && "$(GHC)" -v0 -package-db="$(PACKAGEDB)" -e 'import
 System.FilePath' -e 'takeFileName "foo/bar"'
         @echo
         @echo FAILURE MODE 1C
         @echo
         echo 'import System.FilePath' > temp/Foo.hs
         echo 'main = print $$ takeFileName "foo/bar"' >> temp/Foo.hs
         -cd temp && "$(GHC)" -v0 -package-db="$(PACKAGEDB)" Foo.hs
 -fforce-recomp

 setup2 :
         @echo
         @echo 222222222222222222222222222222222
         @echo - Install package
         @echo - Remove a module from 'exposed-modules'
         @echo - Reinstall package
         @echo - Run some tests
         @echo
         cabal install -v0 --with-ghc="$(GHC)"
         sed -i '/System.FilePath.Posix/d' filepath.cabal
         cabal install -v0 --with-ghc="$(GHC)"

 run2 :
         @echo
         @echo FAILURE MODE 2A, same as 1A
         @echo
         -cd temp && "$(GHC)" -package-db="$(PACKAGEDB)" -e 'import
 System.FilePath.Posix'
         @echo
         @echo FAILURE MODE 2B
         @echo
         -cd temp && "$(GHC)" -package-db="$(PACKAGEDB)" -e 'import
 System.FilePath' -e 'takeFileName "foo/bar"'
         @echo
         @echo FAILURE MODE 2C
         @echo
         echo 'import System.FilePath' > temp/Foo.hs
         echo 'main = print $$ takeFileName "foo/bar"' >> temp/Foo.hs
         -cd temp && "$(GHC)" -package-db="$(PACKAGEDB)" Foo.hs -fforce-
 recomp
 }}}

 Output (run `make`):
 {{{
 # FAILURE MODE 1A
 #
 # cd temp && "ghc-7.10.3" -v0 -package-db="../.cabal-sandbox/x86_64-linux-
 ghc-7.10.3-packages.conf.d/" -e 'import System.FilePath.Posix'
 #
 # <no location info>:
 #     Could not find module ‘System.FilePath.Posix’
 #     It is a member of the hidden package
 ‘filepath-1.4.0.0@filep_Ey7a1in9roBAE8bUFJ5R9m’.
 # make[1]: [run1] Error 1 (ignored)
 #
 # FAILURE MODE 1B
 #
 # cd temp && "ghc-7.10.3" -v0 -package-db="../.cabal-sandbox/x86_64-linux-
 ghc-7.10.3-packages.conf.d/" -e 'import System.FilePath' -e 'takeFileName
 "foo/bar"'
 # <interactive>: Failed to load interface for ‘System.FilePath.Posix’
 # Perhaps you haven't installed the "dyn" libraries for package
 ‘filepath-99999.1.0’?
 # Use -v to see a list of the files searched for.
 # make[1]: [run1] Error 1 (ignored)
 #
 # FAILURE MODE 1C
 #
 # echo 'import System.FilePath' > temp/Foo.hs
 # echo 'main = print $ takeFileName "foo/bar"' >> temp/Foo.hs
 # cd temp && "ghc-7.10.3" -v0 -package-db="../.cabal-sandbox/x86_64-linux-
 ghc-7.10.3-packages.conf.d/" Foo.hs -fforce-recomp
 # Failed to load interface for ‘System.FilePath.Posix’
 # There are files missing in the ‘filepath-99999.1.0’ package,
 # try running 'ghc-pkg check'.
 # Use -v to see a list of the files searched for.
 # make[1]: [run1] Error 1 (ignored)
 }}}

 More output:
 {{{
 # FAILURE MODE 2A, same as 1A
 #
 # cd temp && "ghc-7.10.3" -package-db="../.cabal-sandbox/x86_64-linux-
 ghc-7.10.3-packages.conf.d/" -e 'import System.FilePath.Posix'
 #
 # <no location info>:
 #     Could not find module ‘System.FilePath.Posix’
 #     It is a member of the hidden package
 ‘filepath-1.4.0.0@filep_Ey7a1in9roBAE8bUFJ5R9m’.
 # make[1]: [run2] Error 1 (ignored)
 #
 # FAILURE MODE 2B
 #
 # cd temp && "ghc-7.10.3" -package-db="../.cabal-sandbox/x86_64-linux-
 ghc-7.10.3-packages.conf.d/" -e 'import System.FilePath' -e 'takeFileName
 "foo/bar"'
 # <interactive>:
 # ByteCodeLink.lookupCE
 # During interactive linking, GHCi couldn't find the following symbol:
 #
 filepzuDQlytQXekB83614cuzzvF62_SystemziFilePathziPosix_takeFileName_closure
 # This may be due to you not asking GHCi to load extra object files,
 # archives or DLLs needed by your current session.  Restart GHCi,
 specifying
 # the missing library using the -L/path/to/object/dir and -lmissinglibname
 # flags, or simply by naming the relevant files on the GHCi command line.
 # Alternatively, this link failure might indicate a bug in GHCi.
 # If you suspect the latter, please send a bug report to:
 #   glasgow-haskell-bugs@haskell.org
 #
 # make[1]: [run2] Error 1 (ignored)
 #
 # FAILURE MODE 2C
 #
 # echo 'import System.FilePath' > temp/Foo.hs
 # echo 'main = print $ takeFileName "foo/bar"' >> temp/Foo.hs
 # cd temp && "ghc-7.10.3" -package-db="../.cabal-sandbox/x86_64-linux-
 ghc-7.10.3-packages.conf.d/" Foo.hs -fforce-recomp
 # [1 of 1] Compiling Main             ( Foo.hs, Foo.o )
 # Linking Foo ...
 # Foo.o: In function `sKS_info':
 # (.text+0xae): undefined reference to
 `filepzuDQlytQXekB83614cuzzvF62_SystemziFilePathziPosix_takeFileName_closure'
 # Foo.o: In function `SLc_srt':
 # (.data+0x88): undefined reference to
 `filepzuDQlytQXekB83614cuzzvF62_SystemziFilePathziPosix_takeFileName_closure'
 # collect2: error: ld returned 1 exit status
 # make[1]: [run2] Error 1 (ignored)
 }}}

 == Analysis

 * 1A: why mention a hidden (global) package, when it is hidden by a
 *broken* package.
 * 1B: misleading suggestion about "dyn" libraries
 * 1C: why does GHC say I should run ghc-pkg, but 'ghc-pkg check' says
 everything is fine?

 * 2A: same as 1A
 * 2B: scary: ByteCodeLink.lookupCE
 * 2C: terrible: undefined reference

 == Bonus
 With ghc-8.0.1-rc1, failure modes 1B, 1C, 2B and 2C look like this:

 {{{
 # [1 of 1] Compiling Main             ( Foo.hs, Foo.o )
 #
 # Foo.hs:1:1: error:
 #     Bad interface file: /home/thomas/tmp/test/filepath/.cabal-
 sandbox/lib/x86_64-linux-
 ghc-8.0.0.20160127/filepath-1.4.1.0-87VdeZTuOMDJQ40Wd1kNnE/System/FilePath.hi
 #         Something is amiss; requested module
 filepath-1.4.1.0@filepath-1.4.1.0-435e90352be17e51f8e362eb5810bcd5:System.FilePath
 differs from name found in the interface file
 filep_87VdeZTuOMDJQ40Wd1kNnE:System.FilePath
 # make: [run2] Error 1 (ignored)
 }}}

 Related tickets:
 * https://github.com/haskell/cabal/issues/2982: Cabal will build and
 install broken library if other-modules is not complete
 * https://github.com/haskell/cabal/issues/3093: Missing files in package
 * #9009 Confusing error message when loading package with TH
 * #11023: ghci and ghc-pkg disagree about what's exposed
 * #8060: Undefined symbols when using Template Haskell linked from another
 object with unexposed modules

 #8060 was closed with:
...
GHC is not really in the business of checking the well-formedness of
 archive files installed in the package database, so there is not much GHC
 can do here.
--
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11536
GHC http://www.haskell.org/ghc/
The Glasgow Haskell Compiler

GHC

tags

participants (1)