Universal build and CI testing for Haskell packages

Version on this page:0.4.2
LTS Haskell 22.26:0.6.0
Stackage Nightly 2024-06-19:0.7.0
Latest on Hackage:0.7.0

See all snapshots packcheck appears in

BSD-3-Clause licensed by Harendra Kumar
Maintained by [email protected]
This version can be pinned in stack with:packcheck-0.4.2@sha256:669cc28ae9f24b5b8e0620b5c31e8f11ad42d496b1fe8f3ed991c97b34dfd5db,2759

Module documentation for 0.4.2

Depends on 1 package(full list with versions):


Quick Start

CI (Travis/Appveyor/CircleCI)

To use packcheck for CI testing of your repo:

CI should work out of the box for most packages. Uncomment the relevant lines in the CI config files or change the values of the environment variables for fine grained control or custom configuration.

Local Machine

You can use packcheck to build or CI test a package on your local machine as well. For local use, copy to your local machine (Linux/OSX/Windows), put it in your PATH, and run it from your package directory. You can pass the same evironment variables that are used in CI files to run the exact same tests locally. Usage is as simple as:

$ cabal-v2
$ cabal-v2 GHCVER=8.6.5
$ cabal-v2 ENABLE_GHCJS=y
$ cabal-v1
$ stack GHCVER=8.6

packcheck can automatically pick the requested version of GHC from:

  • multiple GHC path components in your PATH environment variable
  • hvr ghc PPA install directory
  • stack installed ghc binaries

Out of the box support

Platforms Build Types CI Modes Compilers
Linux stack Travis GHC
OSX cabal Appveyor GHCJS
Windows cabal new-build CircleCI
Local Machine

The script can be easily adapted to any CI with a single line build command.

Key Features

  • Error messages: A lot of emphasis has been put on providing precise and detailed error messages when something fails so that the user can easily fix things.
  • Informational: The output provides all the information that you may want to know, tool paths being used, their versions, how they are invoked, build options, time taken by each build step etc. You can even copy the commands from the output and paste them on your local host to reproduce the build or failure and debug quickly. See here for a sample output.
  • Same tests everywhere: You can run exact same tests with same options or flags, in the same way, on all CI platforms.
  • Choose options: Conveniently control all aspects of build through command line or environment variables, including tool options or whether to enable benchmarks, haddock, coverage, install test etc.
  • Picking GHC: Right GHC is picked up automatically from PATH or TOOLS_DIR (hvr ghc PPA installation dir) based on GHCVER. Stack installed GHC binaries can be picked automatically when available.
  • Test source distribution: packcheck creates the source distribution and builds the package from the generated tarball to make sure that you build what you release and don’t miss adding a file to the distribution.
  • Upload coverage: To send coverage info to just uncomment a line in your .travis.yml.
  • Non-destructive: By default the script does not change any config or upgrade any tools on the host machine.
  • Auto tool install: For stack builds, stack and ghc can be installed automatically


The package packcheck includes a script called, it is a high level universal super build script to uniformly, consistently build and comprehensively sanity test a Haskell package across build tools (stack/cabal) and across all platforms (Linux/MacOS/Windows). You do not need to be familiar with any of the build tools to use it.

To make sure that it works everywhere without installing anything it is deliberately written using the bash shell scripting language. Any of the parameters to control the builds can either be passed on the script command line or as environment variables for convenient use on CI systems.

packcheck is also a minimal yet complete “hello world” Haskell package with model travis and appveyor config files that can be used unmodified in any Haskell package. The CI configs can be modified declaratively, using environment variables, to adapt to any kind of build scenario you can imagine.

This model package has everything that a Haskell package usually has; including tests, benchmarks and Linux/MacOS/Windows CI already working. It can be used as a starting point to develop a new package. Beginners can use it to learn about haskell package metadata structure.

What all does it do?

An invocation of performs a whole battery of tests, all aspects can be controlled via environment variables, command line. The flow goes roughly as follows:

  • Pick up the correct version of GHC/cabal/stack
  • create source distribution and unpack it to test from it
  • build source, benchmarks and docs
  • run tests
  • run hlint
  • generate and upload coverage report (to
  • perform distribution checks

Usage Examples

You can run these commands on your local machine as well as inside a CI script. You can try these commands in the packcheck package itself:

$ cd packcheck
$ ./ cabal-v2 GHCVER=8.6.5
$ ./ cabal-v1 GHCVER=7.10.3 CABALVER=1.22
$ ./ stack RESOLVER=lts-13
$ ./ stack GHCVER=8.6.5
$ ./ stack RESOLVER=lts-7.24 STACK_YAML=stack-8.0.yaml STACK_BUILD_OPTIONS="--flag streamly:examples-sdl" CABALVER=1.24
# You can also do a cabal build using stack installed ghc:
$ stack exec ./ cabal RESOLVER=lts-11

Run hlint commands on the directories src and test:

$ ./ stack HLINT_COMMANDS="hlint lint src; hlint lint test"

Send coverage info of the testsuites named test1 and test2 to using hpc-coveralls.

$ ./ cabal-v1 GHCVER=8.0.2 COVERALLS_OPTIONS="test1 test2"

Picking GHC versions

When GHCVER parameter is not specified, packcheck looks for a binary named ghc in your PATH environment variable. It uses first such binary found in PATH.

When GHCVER parameter is specified, it looks for ghc in the PATH and if GHCVER is a PREFIX of the actual version of ghc binary found then that ghc binary is used. Otherwise, packcheck tries to look for another ghc binary in the next PATH components until it finds a matching ghc version.

When both GHCVER and TOOLS_DIR are specified then in addition to searching in PATH environment variable, packcheck also looks for ghc in ${TOOLS_DIR}/ghc/${GHCVER}*/bin. This is to facilitate selecting any GHC version from an hvr/ghc ubuntu PPA installation without putting all the myriad GHC version directories explicitly in your PATH.

If all of the above fails packcheck looks for ghc in the stack install locations.

packcheck-safe is a more robust wrapper over, it does not trust or use any environment variables, all environment needs to be specified explicitly on the command line. Therefore, it ensures better reproducibility.

It also catches any misspelled command line parameter names. For example, won’t catch it if you typed GHCVWR=8.4 instead of GHCVER=8.4, it just assumes that GHCVER is not specified. would generate an error saying that GHCVWR is not recognized. Since it uses a clean environment you will have to specify PATH as well on the command line. For example,

$ ./ cabal-v2 PATH=/bin:/usr/bin:/opt/ghc/bin

Full Reference

NOTE: Any of the parameters described below can either be passed on command line or as an environment variable. Passing options on command line is more convenient when running interactively, while environment variables are more convenient when running on a CI system.

$ --help


For example:
./ stack RESOLVER=lts-10.0 GHC_OPTIONS="-O0 -Werror"

Control parameters can either be passed on command line or exported
as environment variables. Parameters marked DESTRUCTIVE may modify
your global user config or state.

Boolean parameters can be specified as
y|Y|yes|Yes|YES|true|True|TRUE|on|On|ON for an affirmative value and as
n|N|no|No|NO|false|False|FALSE|off|Off|OFF or empty for a negative value.

Commands and flags
cabal-v2                : build using cabal v2-build
cabal-new               : Deprecated alias to cabal-v2
cabal-v1                : build using cabal v1-build
cabal                   : Deprecated alias to cabal-v1
stack                   : build using stack
clean                   : remove the .packcheck directory
cleanall                : remove .packcheck, .stack-work, .cabal-sandbox directories
help | --help | -h      : show this help message
--version               : show packcheck version

Selecting tool versions
ENABLE_GHCJS            : [y] Use GHCJS instead of GHC to build
GHCVER                  : [a.b.c] GHC version prefix (may not be enforced when using stack)
CABALVER                : [a.b.c.d] Cabal version (prefix) to use
RESOLVER                : Stack resolver to use for stack builds or cabal builds using stack
STACKVER                : [a.b.c.d] Stack version (prefix) to use
STACK_UPGRADE           : [y] DESTRUCTIVE! Upgrades stack to latest version

Where to find the required tools
PATH                    : [path] Set PATH explicitly for predictable builds
TOOLS_DIR               : [dir] Find ghc|cabal by version as in TOOLS_DIR/ghc/<version>/bin

Specifying common tool options
GHC_OPTIONS             : Specify GHC options to use
SDIST_OPTIONS           : Arguments to stack/cabal sdist command
CABAL_REINIT_CONFIG     : [y] DESTRUCTIVE! Remove old config to avoid incompatibility issues

Specifying what to build
DISABLE_BENCH           : [y] Do not build benchmarks, default is to build but not run
DISABLE_TEST            : [y] Do not run tests, default is to run tests
DISABLE_DOCS            : [y] Do not build haddocks, default is to build docs
DISABLE_SDIST_BUILD     : [y] Do not build from source distribution
DISABLE_DIST_CHECKS     : [y] Do not perform source distribution checks
ENABLE_INSTALL          : [y] DESTRUCTIVE! Install the package after building

stack options
STACK_YAML              : Alternative stack config, cannot be a path, just the file name
STACK_OPTIONS           : ADDITIONAL stack global options (e.g. -v) to append
STACK_BUILD_OPTIONS     : ADDITIONAL stack build command options to append

cabal options
CABAL_BUILD_OPTIONS     : ADDITIONAL cabal v2-build options to append to defaults
CABAL_BUILD_TARGETS     : cabal v2-build targets, default is 'all'
CABAL_CONFIGURE_OPTIONS : ADDITIONAL cabal v1-configure options to append to defaults
CABAL_CHECK_RELAX       : [y] Do not fail if cabal check fails on the package.
CABAL_NO_SANDBOX        : [y] DESTRUCTIVE! Clobber (force install) global cabal ghc package db
CABAL_HACKAGE_MIRROR    : [y] DESTRUCTIVE! Specify an alternative mirror, modifies the cabal config file.

Coverage options
COVERALLS_OPTIONS       : hpc-coveralls args and options, usually just test suite names
COVERAGE                : [y] Just generate coverage information

hlint options
HLINT_COMMANDS          : hlint commands e.g.'hlint lint src; hlint lint test'

Diagnostics options
CHECK_ENV               : [y] Treat unknown env variables as error, used with env -i
BASE_TIME               : System time to be used as base for timeline reporting

Options marked DESTRUCTIVE! are fine in a CI environment. But on a local machine sometimes it may not be desirable as it will change the state of your global cabal config, so consider that before using these options.

By default cabal builds are done using sandboxes. It creates any temporary files or build artifacts inside .packcheck directory. See the clean and cleanall commands to release the temporary space.

stack is automatically installed and can be used to do cabal builds as well. If you specify BUILD=cabal-v2 and RESOLVER at the same time then the cabal build uses stack installed cabal and ghc, both are installed automatically when needed.

For pure cabal builds i.e. when BUILD=cabal-v2 and RESOLVER is not specified, cabal and ghc must be pre-installed on the system before building.


Sometimes you may run into issues due to some environment variables unknowingly set or some command line parameters or env variables being misspelled and therefore silently ignored. To avoid any such issues the robust way to invoke packcheck is to use a clean environment using env -i and passing CHECK_ENV=y parameter. When this parameter is set unwanted/misspelled variables are detected and reported.

$ env -i CHECK_ENV=y ./ stack

For performance diagnostics packcheck prints the time elapsed from the beginning at each build step performed.



Bug Fixes

  • When building from source distribution, it would not build again unless cleaned with packcheck clean if a file in the source has changed.


  • Deprecate and replace the cabal command with cabal-v1, in future cabal will be used for cabal-v2.
  • Deprecate and replace the cabal-new command with cabal-v2.
  • Use STACK_BUILD_OPTIONS envvar in the dependency install phase as well
  • Remove stack yaml creation using stack init/solver


  • Search for ghc among stack installed GHC binaries as well
  • Add GHCJS support. Use ENABLE_GHCJS=y option.
  • Add . The safe version does not trust or use any environment variables, all environment needs to be specified on the command line. It also catches any misspelled command line parameter names.
  • Allow boolean parameters to be specified with a lenient syntax allowing values y|Y|yes|Yes|YES|true|True|TRUE|on|On|ON|n|N|no|No|NO|false|False|FALSE|off|Off|OFF


  • Disable hpc-coveralls by default


  • Add support for circle CI
  • Add support for multi-package stack as well as cabal repos
  • Add a version command
  • Add CABAL_NEWBUILD_TARGETS envvar to build specific targets
  • Add GHC 8.6.1 in build matrices


  • Add a new environment var option DISABLE_DIST_CHECKS to disable source distribution checks. This can be used as a workaround for a bug in stack causing “stack sdist” to fail.
  • For stack builds, use the same options (STACK_BUILD_OPTIONS) for install test as for build so that an extra rebuild does not occur during install.
  • Workaround to avoid depending on cabal info command; in certain cases this command crashes cabal. See issue #13.



  • Add cabal new-build support. Use cabal-new to use it.
  • Add knobs to disable tests or doc builds (DISABLE_TEST, DISABLE_DOCS)
  • Now you can specify multiple versions of GHC in PATH and packcheck automatically finds the right one based on GHCVER envvar.
  • Add TOOLS_DIR option to specify hvr-ghc style installation of ghc and cabal. A correct version of GHC is automatically picked from this directory.
  • GHCVER and CABALVER variables are now optional in travis config if you specify the cabal and ghc PPAs under apt sources.
  • Run autoreconf if there is a in the package dir


  • TEST_INSTALL option is deprecated, use ENABLE_INSTALL instead


Breaking Changes

  • Make STACK_BUILD_OPTIONS and CABAL_CONFIGURE_OPTIONS append to the existing build/configure options instead of overriding them.
  • Do not enforce specific stack version in CI configs - this is done to avoid failures due to github API limits when upgrading or downgrading.

Bug Fixes

  • Avoid build failures in cases when cabal-install has to be installed and its dependencies may conflict with the current project dependencies.


  • Better documentation in travis and appveyor configs
  • Reduce the number of builds in default config from 11 to 6


  • Enhancement: Nix support; fix bash location to make it work on NixOS and potentially on other systems.


  • Initial release