See https://haskellstack.org for installation and upgrade instructions.

Note: we are releasing a bit earlier than planned due to #3624.

As such, not all the binaries have been built yet, but the commonly

used 64-bit binaries of Linux static, macOS, and Windows are

available.

In addition, the Windows installer and binary has not been

codesigned (we are awaiting validation of a new codesign

certificate), and you may see a “Windows Defender SmartScreen

prevented an unrecognized app from starting” warning when you try

to run them. If so, click on More info, and then click on the Run anyway button that appears.

Major changes since v1.5.1

• Complete overhaul of how snapshots are defined, the packages and extra-deps fields, and a

  number of related items. For full details, please see the writeup on

  these changes. PR #3249, see the PR description for a number of related issues.

• Upgraded to version 2.0 of the Cabal library.

Behavior changes

• The --install-ghc flag is now on by default. For example, if you run stack build in a directory

  requiring a GHC that you do not currently have, Stack will

  automatically download and install that GHC. You can explicitly set

  install-ghc: false or pass the flag --no-install-ghc to regain the previous behavior.

• stack ghci no longer loads modules grouped by

  package. This is always an improvement for plain ghci - it makes

  loading faster and less noisy. For intero, this has the side-effect

  that it will no longer load multiple packages that depend on TH

  loading relative paths. TH relative paths will still work when

  loading a single package into intero. See #3309

• Setting GHC options for a package via ghc-options: in your stack.yaml will promote it to a local package,

  providing for more consistency with flags and better

  reproducibility. See: #849

• The package-indices setting with Hackage no longer works with the 00-index.tar.gz tarball, but must use the 01-index.tar.gz file to allow revised packages to be found.

• Options passsed via --ghci-options are now passed

  to the end of the invocation of ghci, instead of the middle. This

  allows using +RTS without an accompanying -RTS.

• When auto-detecting --ghc-build, tinfo6 is now preferred over standard if both versions of libtinfo are installed

• Addition of stack build --copy-compiler-tool, to

  allow tools like intero to be installed globally for a particular

  compiler. #2643

• Stack will ask before saving hackage credentials to file. This

  new prompt can be avoided by using the

  save-hackage-creds setting. Please see #2159.

• The GHCRTS environment variable will no longer be

  passed through to every program stack runs. Instead, it will only

  be passed through commands like exec, runghc, script, ghci, etc. See #3444.

• ghc-options: for specific packages will now come

  after the options specified for all packages / particular sets of

  packages. See #3573.

• The pvp-bounds feature is no longer fully

  functional, due to some issues with the Cabal library's printer.

  See #3550.

Other enhancements:

• The with-hpack configuration option specifies an

  Hpack executable to use instead of the Hpack bundled with Stack.

  Please see #3179.

• It's now possible to skip tests and benchmarks using --skip flag

• GitSHA1 is now StaticSHA256 and is implemented using the StaticSize 64 ByteString for improved performance. See #3006

• Dependencies via HTTP(S) archives have been generalized to

  allow local file path archives, as well as to support setting a

  cryptographic hash (SHA256) of the contents for better

  reproducibility.

• Allow specifying --git-branch when upgrading

• When running stack upgrade from a file which is

  different from the default executable path (e.g., on POSIX systems,

  ~/.local/bin/stack), it will now additionally copy the new executable over the currently running stack

  executable. If permission is denied (such as in

  /usr/local/bin/stack), the user will be prompted to try again using sudo. This is intended to assist with the user experience when the PATH environment variable has not been properly configured, see #3232.

• stack setup for ghcjs will now install alex and happy if they are not present. See #3109.

• Added stack ghci --only-main flag, to skip loading

  / importing all but main modules. See the ghci documentation page

  for further info.

• Allow GHC's colored output to show through. GHC colors output

  starting with version 8.2.1, for older GHC this does nothing.

  Sometimes GHC's heuristics would work fine even before this change,

  for example in stack ghci, but this override's GHC's

  heuristics when they're broken by our collecting and processing

  GHC's output.

• Extended the ghc-options field to support $locals, $targets, and $everything. See: #3329

• Better error message for case that stack ghci file targets are combined with invalid package targets. See: #3342

• For profiling now uses -fprof-auto -fprof-cafs instead of the deprecated -auto-all -caf-all. See: #3360

• Better descriptions are now available for stack upgrade --help. See: #3070

• When using Nix, nix-shell now depends always on gcc to prevent

  build errors when using the FFI. As ghc depends on gcc anyway, this

  doesn't increase the dependency footprint.

• --cwd DIR can now be passed to stack exec in order to execute the program in a different directory. See: #3264

• Plan construction will detect if you add an executable-only

  package as a library dependency, resulting in much clearer error

  messages. See: #2195.

• Addition of --ghc-options to stack script to pass options directly to GHC. See: #3454

• Add hpack package.yaml to build Stack itself

• Add ignore-revision-mismatch setting. See: #3520.

• Log when each individual test suite finishes. See: #3552.

• Avoid spurious rebuilds when using --file-watch by

  not watching files for executable, test and benchmark components

  that aren't a target. See: #3483.

• Stack will now try to detect the width of the running terminal

  (only on POSIX for the moment) and use that to better display

  output messages. Work is ongoing, so some messages will not be

  optimal yet. The terminal width can be overriden with the new

  --terminal-width command-line option (this works even on non-POSIX).

• Passing non local packages as targets to stack ghci will now cause them to be used as -package args along with package hiding.

• Detect when user changed .cabal file instead of package.yaml. This was implemented upstream in hpack. See #3383.

• Automatically run autoreconf -i as necessary when a configure script is missing. See #3534

• GHC bindists can now be identified by their SHA256 checksum in

  addition to their SHA1 checksum, allowing for more security in

  download.

• For filesystem setup-info paths, it's no longer assumed that the directory is writable, instead a temp dir is used. See #3188.

Bug fixes

• stack hoogle correctly generates Hoogle databases. See: #3362

• stack --docker-help is now clearer about –docker

  implying system-ghc: true, rather than both –docker and

  –no-docker.

• stack haddock now includes package names for all modules in the Haddock index page. See: #2886

• Fixed an issue where Stack wouldn't detect missing Docker images properly with newer Docker versions. #3171

• Previously, cabal files with just test-suite could cause build to fail (#2862)

• If an invalid snapshot file has been detected (usually due to

  mismatched hashes), Stack will delete the downloaded file and

  recommend either retrying or filing an issue upstream. See #3319.

• Modified the flag parser within Stack to match the behavior of

  Cabal's flag parser, which allows multiple sequential dashes. See

  #3345

• Now clears the hackage index cache if it is older than the

  downloaded index. Fixes potential issue if stack was interrupted

  when updating index. See #3033

• The Stack install script now respects the -d option. See #3366.

• stack script can now handle relative paths to source files. See #3372.

• Fixes explanation of why a target is needed by the build plan,

  when the target is an extra dependency from the commandline. See

  #3378.

• Previously, if you delete a yaml file from ~/.stack/build-plan,

  it would trust the etag and not re-download. Fixed in this

  version.

• Invoking stack --docker in parallel now correctly locks the sqlite database. See #3400.

• docs.haskellstack.org RTD documentation search is replaced by the mkdocs search. Please see #3376.

• stack clean now works with nix. See #3468.

• stack build --only-dependencies no longer builds local project packages that are depended on. See #3476.

• Properly handle relative paths stored in the precompiled cache files. See #3431.

• In some cases, Cabal does not realize that it needs to

  reconfigure, and must be told to do so automatically. This would

  manifest as a “shadowed dependency” error message. We now force a

  reconfigure whenever a dependency is built, even if the package ID

  remained the same. See #2781.

• When --pvp-bounds is enabled for sdist or upload,

  internal dependencies could cause errors when uploaded to hackage.

  This is fixed, see #3290

• Fixes a bug where nonexistent hackage versions would cause

  stack to suggest the same package name, without giving version

  info. See #3562

• Fixes a bug that has existed since 1.5.0, where stack setup --upgrade-cabal would say that Cabal is already the latest version, when it wasn't.

• Ensure that an extra-dep from a local directory is not treated as a $locals for GHC options purposes. See #3574.

• Building all executables only happens once instead of every time. See #3229 for more info.

Contributors

Thanks to all our contributors for this release:

• Aaron McDaid

• Adam McCullough

• Alexey Zabelin

• Andy

• Ashley Towns

• Chris Done

• Chris Martin

• d-dorazio

• Deni Bertovic

• Dmitry Ivanov

• Echo Nolan

• Emanuel Borsboom

• Felix Yan

• Filippo Vitale

• Gábor Lipták

• Ivan Lazar Miljenovic

• Joshua Simmons

• Judah Jacobson

• Khan Thompson

• Lizao Li

• Luke Murphy

• Martin Kolinek

• Mathieu Boespflug

• Matt Audesse

• Matthias Heinzel

• Michael Sloan

• Michael Snoyman

• mrkkrp

• Neil Mitchell

• Oleg Grenrus

• OvermindDL1

• Paolo G. Giarrusso

• Rafe

• Reuben D'Netto

• Roman Cheplyaka

• Samuli Thomasson

• Schlueter

• Scott Fleischman

• Shea Levy

• Simon Jakobi

• Tom Sydney Kerckhove

• tswelsh

• Walter Franzini