Ticket #7779 (new bug)
building GHC overwrites the installed package database if GHC_PACKAGE_PATH is set
|Reported by:||heatsink||Owned by:||igloo|
|Type of failure:||None/Unknown||Difficulty:||Unknown|
|Test Case:||Blocked By:|
When building GHC, if GHC_PACKAGE_PATH is set to a single path, then the build process will register packages in that path instead of in the build tree. Since GHC_PACKAGE_PATH points to the host compiler's package database, the build system overwrites the host compiler's package database, rendering the host compiler unusable.
1. Get a binary distribution of GHC 7.4.1 and a source distribution of GHC 7.4.2
2. Configure the binary distribution to install in a temporary directory: ./configure --prefix=$HOME/workspace1
3. Install the binary distribution
4. Set up the environment to use only the installed compiler: export PATH=$HOME/workspace1/bin:$PATH; export GHC_PACKAGE_PATH=$HOME/workspace1/lib/ghc-7.4.1/package.conf.d
5. Configure the source distribution to install in a different directory: ./configure --prefix=$HOME/workspace2
6. Build the source distribution: make
Building will eventually run commands that modify the package database in GHC_PACKAGE_PATH. One of these commands is "inplace/bin/ghc-pkg" update --force rts/package.conf.inplace. I confirmed that the database is being modified by making ghc-pkg print the name of the file it's about to update.