#7779: building GHC overwrites the installed package database if GHC_PACKAGE_PATH is set -----------------------------+---------------------------------------------- Reporter: heatsink | Owner: Type: bug | Status: new Priority: normal | Component: Build System Version: 7.4.2 | Keywords: Os: Unknown/Multiple | Architecture: Unknown/Multiple Failure: None/Unknown | Blockedby: Blocking: | Related: -----------------------------+---------------------------------------------- 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. To reproduce: 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. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/7779 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler