When passing a package database to ghc-pkg via `GHC_PACKAGE_PATH` or `--package-db`, `${pkgroot}` does not get computed properly if the input

#12196: ghc-pkg should drop trailing path separator when computing package database root -------------------------------------+------------------------------------- Reporter: bgamari | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.0.2 Component: Package | Version: 8.0.1 system | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Reported on `ghc-devs@`, Nicolas Dudebout writes, path contains a trailing slash.

Default behavior: {{{ $ ghc-pkg describe base | grep pkgroot pkgroot: "/usr/lib/ghc-7.10.2" }}}

Correct behavior (no trailing slash): {{{ $ ghc-pkg --package-db /usr/lib/ghc-7.10.2/package.conf.d describe

base

| grep pkgroot pkgroot: "/usr/lib/ghc-7.10.2"

$ GHC_PACKAGE_PATH=/usr/lib/ghc-7.10.2/package.conf.d ghc-pkg describe base | grep pkgroot pkgroot: "/usr/lib/ghc-7.10.2" }}}

Incorrect behavior (with trailing slash): {{{ $ ghc-pkg --package-db /usr/lib/ghc-7.10.2/package.conf.d/ describe base | grep pkgroot pkgroot: "/usr/lib/ghc-7.10.2/package.conf.d"

$ GHC_PACKAGE_PATH=/usr/lib/ghc-7.10.2/package.conf.d/ ghc-pkg describe base | grep pkgroot pkgroot: "/usr/lib/ghc-7.10.2/package.conf.d" }}}

When this bug happens, `ghc-pkg` check complains about missing files for packages using `${pkgroot}`.

This bug happens because `${pkgroot}` is computed using `takeDirectory`. It should instead use `(takeDirectory . dropTrailingPathSeparator)`.

-- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12196 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler