ghc-pkg, recompilation check

[Serge D. Mechveliani]

Dear GHC developers and users, 

Could you, please, help with  ghc-pkg ?   
(in  ghc-6.4)

The contrived testing project is of the two small modules  
M1.hs, M2.hs.
(find enclosed the source).
`Makefile' is set so that   make dm

should compile the modules and put  *.hi, *.o modules and .a, .o  
libraries to  $(s)/export/.
It also needs to create a package  dm-1.0   (in 6.2.2 it was  dm ).
A particular command in Makefile is

  ghc-pkg -f $(s)/dm-1.0.conf -u -g

, which (as I recall) makes the .o library from .a one.
It worked in 6.2.2 
-- with  dm  instead of  dm-1.0,  with `=' instead of `:'  and
with  
     package_deps = ["data"]
in the package specification.

And in  6.4,   make dm 
reports 
...
" Reading package info from stdin... done.
  ghc-pkg: invalid package identifier: 
"

Packages always were difficult. And in 6.4 they are changed again ...


Question 2: recompilation
-------------------------

Why does it recompile both modules when after the first  make dm
we remove the  .a  library and repeat                    make dm
?
This recompilation bites when there are many modules.

Thank you in advance for explanation.

------------------
Serge Mechveliani
mechvel at botik.ru




------------------------------------------------------------
module M1                        -- file  M1.hs
where
tuple31 :: (a, b, c) -> a
tuple31    (x, _ ,_) =  x

---------------------------------  file  M2.hs
module M2
where
import qualified Data.Set as Set (Set(..), singleton)

import M1 (tuple31)

f :: Set.Set Bool
f =  Set.singleton $ tuple31 (True, False, False)


-- Makefile ------------------------------------------------------

ghcBinDir = /usr/bin
s         = /home/mechvel/ghc/6.4/pkgTest
e         = $(s)/export
ghc       = $(ghcBinDir)/ghc
ghcpkg    = $(ghcBinDir)/ghc-pkg
RANLIB    = ar -s
HCFlags   = -odir $(e) -hidir $(e) -ddump-hi-diffs

pack = Package {name            : ["\"dm-1.0\""], \
                import_dirs     : ["\"$(e)\""], \
                source_dirs     : [],           \
                library_dirs    : ["\"$(e)\""], \
                hs_libraries    : ["\"HSdm\""], \
                extra_libraries : [], \
                include_dirs    : [], \
                c_includes      : [], \
                package_deps    : [], \
                extra_ghc_opts  : [], \
                extra_cc_opts   : [], \
                extra_ld_opts   : [] }

# of 6.2.2:  name         = ["\"dm\""], \
#            package_deps = [\"data\"], \

obj:
	if [ ! -d $(e) ]; then mkdir $(e); fi
	$(ghc) $(HCFlags) --make M2  -package-name dm-1.0  

dm: obj
	rm -f  $(e)/libHSdm* $(e)/HSdm*
	ar -qc $(e)/libHSdm.a $(wildcard $(e)/*.o)
	$(RANLIB)  $(e)/libHSdm.a
	$(RANLIB)  $(e)/libHSdm.a
	echo $(pack) | $(ghcpkg) -f $(s)/dm-1.0.conf -u -g
	$(ghcpkg) -f $(s)/dm-1.0.conf -l
------------------------------------------------------------------



  make dm

yields

-----------------------------------------------------------
if [ ! -d /home/mechvel/ghc/6.4/pkgTest/export ]; 
then mkdir /home/mechvel/ghc/6.4/pkgTest/export; fi
/usr/bin/ghc -odir /home/mechvel/ghc/6.4/pkgTest/export 
-hidir /home/mechvel/ghc/6.4/pkgTest/export -ddump-hi-diffs 
--make M2  -package-name dm-1.0  
Chasing modules from: M2
    Source file changed or recompilation check turned off
Compiling M1   ( ./M1.hs, /home/mechvel/ghc/6.4/pkgTest/export/M1.o )
No old interface file

    Source file changed or recompilation check turned off
Compiling M2       ( M2.hs, /home/mechvel/ghc/6.4/pkgTest/export/M2.o )
No old interface file

rm -f  /home/mechvel/ghc/6.4/pkgTest/export/libHSdm*
        /home/mechvel/ghc/6.4/pkgTest/export/HSdm*
ar -qc /home/mechvel/ghc/6.4/pkgTest/export/libHSdm.a 
   /home/mechvel/ghc/6.4/pkgTest/export/M1.o 
   /home/mechvel/ghc/6.4/pkgTest/export/M2.o
ar -s  /home/mechvel/ghc/6.4/pkgTest/export/libHSdm.a
ar -s  /home/mechvel/ghc/6.4/pkgTest/export/libHSdm.a
echo Package {name            : ["\"dm-1.0\""], 
  import_dirs     : ["\"/home/mechvel/ghc/6.4/pkgTest/export\""], 
  source_dirs     : [], 
  library_dirs    : ["\"/home/mechvel/ghc/6.4/pkgTest/export\""], 
  hs_libraries    : ["\"HSdm\""], extra_libraries : [], 
  include_dirs    : [], 
  c_includes      : [], 
  package_deps    : [], 
  extra_ghc_opts  : [], 
  extra_cc_opts   : [], 
  extra_ld_opts   : [] } 
 | 
 /usr/bin/ghc-pkg -f /home/mechvel/ghc/6.4/pkgTest/dm-1.0.conf -u -g

Reading package info from stdin... done.
ghc-pkg: invalid package identifier: 
make: *** [dm] Error 1
----------------------------------------------------------